Adobe Q & A

What is Adobe?

Question: What does ADOBE mean or stand for?

Answer: Adobe soil has clay and sand in such proportions that when mixed into mud then dried out it forms a brick or a wall. An adobe brick is made of adobe soil and is sun cured on the ground. Adobe mortar may have more clay than plaster, floors or bricks. It sticks adobe bricks together to create a wall. Adobe plaster is that which uses clay as the primary binder. An adobe floor may be made of adobe bricks laid flat on a dirt, sand, or gravel base. Joints may be filled with adobe mortar, cement grout, sand or nothing. Adobe floors are more often made by pouring adobe mud over the base in one thick or several thin layers to give a monolithic floor somewhat like concrete. An Adobe home is made of adobe bricks or monolithic adobe walls. Adobe stands forever if it has a good foundation and a good roof and has occupants who give it a bit of periodic maintenance.

Adobe Localities?

Question: I am involved in the design for a passive solar home in Maryland. Are you aware of any sources of adobe bricks on the east coast, or do you suspect we would have to cast our own?

Answer: I don't know of anyone making adobe bricks in the area at the moment. A manufacturer in this area has shipped them to Washington, D.C. That is not viable unless cost is no object. Bricks were made by English immigrants in Geneva, NY, some Amish or Quakers for barns and sheds in PA, and there were two rammed earth homes in DC. So the project would be unique in this time but not without precedent.

Question: I would like to build an adobe garage for my Harley Davidson. I live in Nashville. The climate is quite wet here. Should this cause any problems? Will my garage just turn to wet mud. Yuck what a mess. Also do you think the leaking oil will cause any problems with the foundation.

Answer: Is this a prank message from my cousin Kent in Nashville, the only person I know who has a Harley that leaks oil? Nashville is a fine place for adobe. The garage should not be in a valley subject to flooding or puddling. A good foundation with a concrete or block stem wall that gets eight inches above the finished grade would be in order. Finish it off with a good pitched roof with at least twelve or sixteen inches of overhang and the walls will be fine. Cement based stucco on the exterior would be a good idea, too. The major obstacle will be making or importing adobes. About three weeks of dry, sunny weather are needed to make adobes on the ground. Walls can be built during intermittent rain as long as they are kept covered between work sessions. The final problem will be that upon completion the Harley will be living in a building that is stronger and in many other ways superior to the dwelling of its human companions. I wouldn't want it any other way for my bike, either.

Question: In Nova Scotia it is very cold and we just do not build Adobe houses, or anything Adobe, let alone Mexican for that matter. There simply aren't any professionals dedicating any time to the "real thing" here. There would be no way to build a house here unless one is prepared to pay double, or perhaps triple the price. And some of us aren't millionaires! Hence I ask myself - "What is the next best thing to achieve the Mexican look"? The fact that people do like the Mexican Adobe design style is a compliment, especially if they are trying to duplicate the style.

Answer: I am sure there are earthen homes somewhere in NS but they will indeed be few and far between. When the Pilgrims hit the beach in Massachusetts, they had no clue how to build, nor did they have tools. Their first winter was in dugout earthen structures. It took some time to develop abilities and acquire tools to build the log homes we usually think of. There are Viking sites all up and down the coast up into Labrador which were stones mortared together with mud. Many of these coastal areas had no trees that could be used for structures anywhere nearby so even more modern builders would have used some masonry until roads were available to bring in trees and lumber. There are plenty of examples of earthen homes in Ireland, England and Scotland. There is, in fact, a new blossoming of such building techniques. Time has arrived for NS to follow suit.

Question: I would like to hire a builder to design an adobe home for my family and me in Florida. Is it possible? I recently got divorced and lost a home in the process, which means that my credit is bad. What are my options?

Answer: There is almost no adobe construction in Florida. Rammed earth buildings are found in the Carolinas and there is a history of adobe homes in the Black community around Tuscaloosa, Alabama. If you build yourself and make your own bricks, adobe can save some money but not a lot. If you have someone else build and import the adobe bricks from the nearest brickmaker which could be Texas, the cost will be astronomical. There are a couple of community colleges in Florida which have courses to teach owner/builders. If you stay in Florida it will save money to go with the prevailing style and type of building.

P.S. The early near adobe material used in Florida was called tabby or "tapia." Here is a website with more information: tabby

Question: I recently bought property in north east Florida. It is on high elevation so no worry about flooding here. I was thinking about building an adobe home because I like the look and durability. So I was wondering if building an adobe home on my property would be a good choice considering it is not the most dry - it rains quite a bit there as you probably know. I would really like to know. If it is not a good idea, could you suggest another option.

Answer: There are rammed earth homes and churches in the Carolinas. An African/American community built adobe homes in the 1930's somewhere in NW Alabama. English immigrants built homes of adobe brick in Geneva, NY. If you have three weeks of sunny weather, that is enough time to make bricks. Exhausting. Then you can lay up walls in slightly less sunny weather by covering the walls should it rain. All homes, frame, block, metal, need good foundations well above ground and surface water. They all need a good roof with plenty of overhang. Florida is the home of good roofs with lots of overhang. The fact that it is adobe should not stop you. Finding support in your area might be the deal breaker. The Spanish in north Florida built with some wonderful stuff the name of which I cannot remember. The Fort at St Augustine is an example.

Question: We want to build an adobe house and cabin here in N.W. Montana and have spent many hours trying to find someone with experience in building in this area but without success. We live in a dry valley (10-12" of precip./year) with temps that can go as low as 30 below (but very rarely). Is the reason for the lack of adobe construction here that it is impractical in light of the above climate?

Answer: Adobe would be a perfect material to use in your area. Elongate the house east and west and put extra glass on the south and very little on the north, modest amounts on the east and west. The house will do nicely in that climate unless you are in that part of Montana where it tends to be cloudy during the day and clear at night. Here in NM, the heart of adobe country we experience similar very cold nighttime temperatures in the winter. It usually warms up 30 degrees in the daytime. To meet the NM Energy Conservation Code, we apply exterior insulation. It is usually rigid polystyrene or polyurethane nailed or sprayed on the walls. Standard cement/lime based stucco goes over that.

Question: My wife and I love the Adobe look and would love to own an Adobe home. However, we live in southwest Missouri and it does not appear to be a common local building ingredient. Can I use local material to make adobe? If so, what do I look for in the ingredients? Also, because we do not experience long sunny dry spells, is there a different method of drying? By making smaller bricks would I shorten the drying time?

Answer: I don't know about Missouri's adobe history but if you get extremely southwest in the state you are into Oklahoma which has extensive use of adobe, particularly in the Great Depression Era. Missouri is probably just one giant adobe brick waiting to be formed into smaller, easily handled units. You need about 30% clay and silt and the rest sand to make a good adobe brick. Straw helps when there is too much clay to keep the bricks from cracking as they dry. PG McHenry's book Adobe Build it Yourself published by the University of Arizona Press is the best book to get started.

Question: I have a lot for a house in Lee County (Lehigh Acres), FL -Gulf Side- and I'm interested in building a Spanish style home on it. The land is uncleared (bushes and trees) and I'm wondering how well Adobe-built homes would fare in the hurricane-prone, damp climate of southwest Florida?

Answer: Adobe will work just fine. As it turns out earthen building materials are actually just a little bit stronger in lab tests at higher humidities than here in the arid Southwest. (60% ambient humidity is the peak strength.) It needs a concrete foundation that gets six-inches above the finished exterior grade and four-inches above the finished floor level or any potential standing water. The foundation should have a moisture barrier on top of it to stop capillary action which might move moisture upward. A good roof with overhanging eaves would be highly recommended. In the Southwest, many adobe homes have parapet walls and flat roofs but up in the high country where there is more rain and lots of snow, the steeply pitched mountain village architecture predominates. In short, adobe requires no more or less protection from moisture than wood or steel framed structures.

The big problem to solve will be making adobes. Two men after a little conditioning can make 300 adobes per day and if they are brutes, 500. A modest sized home, 1800 sq ft, can be built with 5000 to 7000 adobes of the slightly odd 10x14x4 New Mexico Standard Size. At the 300/day rate it would take 23 days of production to make the 7000 bricks so a four-week window of mostly sunny weather is needed.

There are some machines that can make bricks on site quickly. The ones that rely on ferocious hydraulic pressure to create bricks should be viewed with caution. Moisture for sure, and high humidity perhaps can cause them to "blossom" a kind word to describe expanding and losing their strength. That won't happen to regular cast-on-the-ground, sun-dried-bricks. Also, it is better to find someone who will roll on to your site to make bricks than for you to acquire the machinery yourself. Even if you resell it, you take a big hit in depreciation. Bricks can be purchased in NM or Texas production yards and trucked to FL. Transportation costs will be about double the cost of the bricks themselves.

There are famous and successful churches in the Carolinas built of rammed earth. Church of the Holy Cross in Sumpter South Carolina first comes to mind. A famous rammed earth structure, Hilltop House at 1500 Rhode Island Ave NE, was built in Washington DC. Built before the Stone House in Georgetown, it would be the oldest house in the area except it got torn down in the 1950's for urban renewal! A doctor with the USDA built a home not far from the Capitol Area in the 1930's. It still existed as of 1996. The DC area was essentially a swamp and is still probably as wet as Lee County.

Question: I live in central Wisconsin, and am wondering if adobe would work in this area; How would that work with freezing cold winters.....Are there any areas that adobe would NOT be advantageous?

Answer: Adobe will work just fine in central Wisconsin. Probably very few people have built there with adobe but there are surprises all around the country. English immigrants built simple cottages and stately homes in the Fingerlakes region of New York. There are at least thirteen known structures and three of them are on the market. They were built from 1840 to 1860 for the most part.

Washington, DC has two known adobes built in the 1930's and a huge palatial home, the Hilltop House at 1600 Rhode Island Avenue, NW survived from 1774 until the late 1950's when it was razed for low-income housing. There are famous churches in North Carolina and homestead buildings in Alaska. Mennonites built adobe homes in and around Hillsboro, Kansas.

Adobe's cousin sod, was built all over the plains and probably the SW corner of Wisconsin. Wherever there is an area with few trees when the first immigrants arrived, there is a good chance that they built with adobe, rammed earth or sod up until the time the railroads arrived.

Lots of Irish cottages with thatched roofs are built of adobe. Scandinavians used various forms of earthen construction especially earth as the infill for half-timbered houses. Germans, French, English, Bali Hai. Manitoba recently. Adobe was found all over the USA during the Great and Grand Depression. East Germans used it widely while The Berlin Wall and Iron Curtain were up. Slovakia, Czech Republic, Estonia, Bulgaria, Yugoslavia, Ditto. The list goes on.

All you need is a good foundation that gets 8-inches above the ground level and a good roof with generous overhangs. Wisconsin is not the place for the round, warm, brown, Santa-Fe style adobe home. New Mexico adobe homes in the higher elevations where we get a lot of snow have pitched roofs with good overhang. This is just the type of construction details needed for any type of wall in Wisconsin, not just adobe.

Now, the one problem you do face is whether there is a three-week window of mostly sunny weather in the summer so you can make adobes and have them dry out enough to stack off to the side with a cover when the rain comes. You need soil with 70%sand and 30% clay or less. If there is too much clay in your topsoil, adobes will crack. Dig deeper and you will find strata of sand somewhere under the topsoil. There will also be layers of clay and gravel thanks to convenient glacier activity a few years back.

Building walls is not such a problem. You can cover them if rain threatens and they survive a certain amount of rain with little damage. Be prepared to move on with roof construction as soon as the walls are up and get the building dried in. Wood frame, and other builders do the same. For your climate, a scheme to apply insulation to the exterior of the adobe walls will pay off with much reduced heating costs. Just as it took until the mid-1950's for builders to figure out that frame houses should be insulated, it took until the 1970's for us to see the advantage and in your climate, necessity, really, to insulating. Put lots of glass on the south and you will have the best possible passive solar home. If you think it will not work, look around your neighborhood. If there are photo-voltaic panels at work producing electricity from the sun, then there is enough energy coming in for passive solar heat. Cloudy days hold in the heat so even if you do not have the input we have here in NM, you don't have the loss, either.

Call me when you are done and I will help you select interior wall colors. Adobe paints nicely with oil or latex paints.

Question: I live in Laos, in Southeast Asia and run an international humanitarian development organization (Village Focus International). My wife, who is Lao, and I have just bought a beautiful piece of land on the Mekong River and will build a house there in the next 5 or so years. We hope to build a big (2 story, 3 and half to 4000 square feet) home. Can this be done with Adobe (or strawbale or other alternatives). Is adobe appropriate for this hot, wet climate? Labor is cheap, and clay, sand and gravel is readily available. Any thoughts?

Answer: Germans have built millions of earthen structures in Central Germany. English Immigrants built adobe homes in Geneva, NY and various parts of Canada. Brazilians have built adobe buildings several stories high along the Amazon in that city with the famous old opera house. Adobe homes are built in parts of India and Bangladesh where the moisture is so severe, they get washed away almost annually. You can build some form of earthen structure in Laos whether it's sun-cured adobe bricks, compressed earth blocks, rammed earth, or monolithic adobe which is called cob in some places. You need a foundation that gets the adobe above the ground level and a good roof. That is the same requirement for any type of house which will last over time. There is some evidence that adobe is less prone to mildew and mold than certain other building materials.

C1: Having spent a year only a couple of hundred miles from central Laos, I strongly suspect that adobe would not be suitable. South East Asia monsoons are a memorable experience - 30-45-60 days of non stop downpour was my experience through two monsoon seasons. Regular stick and stone structures even took a beating. The rain in the monsoon season makes the California rains seem like spring showers. After the first 30 days of the monsoon season- every piece of my clothing and gear had mold of various colors - everywhere. I recall one thunderstorm lasting 18 hours non-stop - it was an amazing experience. I also recall that most structures - even large 5 bedroom bungalows were built on stilts. I visited many isolated villages and all the small homes were on stilts made of bamboo sticks and bamboo leaves. The rain knocked the leaves off - the villagers put new ones back. I do not recall ever seeing a home made of mud - except for some earthen plaster on some.

To make a bad pun - I don't mean to rain on Rick's parade - but I just don't see how it would work. If Rick can find any local structures built in the area with adobe like blocks - then by all means get the mud formula and history of the buildings. As far as I know most all S.E.A. experiences the monsoon season. I also recall that when building office buildings - 5 or 6 stories high - instead of digging a basement foundation the engineers built the basement above ground - then diverted streams of water into the foundation around the building - then over several weeks managed a controlled sinking of the basement into the mud to the first floor level. Wow! I could be wrong - but I would check with a lot of locals first - who have experience there.

C2: "Mudbrick and Earth Building the Chinese Way" is an excellent book. It is written by Ron Edwards and Lin Wei-Ho - ISBN 0 909901 34 1. The dust jacket says Lin Wei-Ho lives in Kunming, China which is just over the border from you. It goes on to say his research indicates that 95% of the buildings in the countryside around Kunming are of earth construction. A sketch on page 32 describes some farm buildings in nearby Leshan, Sichuan Province. A metre and a half of rains falls here annually, that's about 49 inches. These buildings have wide eaves. I would think that Quentin's suggestion of the wide eaves (a veranda even) and dry foundations is very sensible. An earth building that caters for sufficient air flow should avoid humidity problems such as damp on the walls and provide for a very livable dwelling. Ron Edwards lives in a mudbrick house in Kuranda, tropical Nth. Queensland where the average annual rainfall is approximately 2 metres or 79 inches.

C3: Below: Excerpts from several references found relative to building materials used in Laos (over time). Evidently Laos is not southern China. I was thinking Quentin should incorporate the Laotian mortar recipe (below) into an adobe mix - a type of adobe aroma therapy built into the blocks. HA!

Laotian mortar recipe: 'Two stone-masons, aged 75 and 85, provided the recipe for traditional Laotian mortar: stew buffalo-hide for nine hours, add crushed yang bong bark, tamarind seeds, chopped rice straw (soaked in water for two days), some markfen leaves, khi bi resin, and a measure of sugar-cane juice. Pour them all together into a mix of lime and Mekong sand, and stir.'

French Colonial Architecture in Laos: As pre-colonial non-religious structures were built with wood, no secular buildings still exist from those periods. When the French first came to Luang Prabang in 1864, they used the fired brick and ceramic roof tile previously reserved for the wats (Buddhist Temple / Monastery) to build their homes and administration buildings. The result was an array of white-washed colonial style edifices: houses with wrought iron balconies, hotels with large verandas, schools and administration buildings with black shutters and high ceilings. With many buildings refurbished as hotels and restaurants, even a bank, Luang Prabang has appropriated colonial architecture, maintaining an air of its recent past.

The Characteristic Buddhist Temple buildings of Laos are all Wooden construction, on wooden pillars, with long, steep, stepped-out roofs. Flamboyant finials mark the up curved ends of the ridgepoles and the eaves extend to cover wide verandas. The Vat Pbraphra Kheo, Vientiane. Rebuilt in the nineteenth century Faint echoes of Khmer style are here incorporated into a characteristic local type of wooden building.

'External finishes to the building are concrete, masonry, rendered and painted with long wearing coatings as commonly used in Laos.'

Kleiwerks an international grassroots natural building organization is pioneering earthen house building in Laos. They work with permaculture principles and appropriate design, incorporating materials such as clay, sand, straw, bamboo, stone, wood, rice husk, urbanite, glass bottles, and whatever else is re-usable or local to the particular areas we are building in. The techniques they have incorporated include: adobe; wattle and daub; cob; strawclay/slipstraw; timber-frame; strawbale; earthen plasters, paints and floors; living and thatch roofs; drystack stone and earth bag foundations; decorative and structural bamboo; and other innovations.

Question: Is central South Carolina a good place for an adobe house? I notice that you thought Nashville would be o.k. We have similar weather--not quite as cold.

Answer: There is the famous Church of the Holy Cross in Sumpter, SC. You should get "Adobe Build it Yourself" by PG Mc Henry, Jr. from the University of Arizona Press. About $25. Another of his books, "Adobe and Rammed Earth Buildings" has the photo of the church.

Mixes for Adobe?

Question: I want to make miniature adobe houses for my son's Santa Fe train city. I cannot seem to find any specific directions. I noticed that your article on this site said you had made them before. Can you help me with instructions?

Answer: Little adobes can be made many ways. The simplest might be to fill a cookie sheet with mud. It is easiest if the cookie sheet has low sides around it, about a half inch. Then the mud can easily be scraped off level with a knife, trowel or short board. Little adobes of most any size can then be cut with a pizza rolling knife. An inch wide by an inch and a half long is a good size. Then put the mud in the oven at about 225 degrees for 10 to 20 minutes. The bricks may have stuck together a bit but they will break apart easily enough. The mud mixture should be mostly sand - about 70% and the rest clay. Many soils out your back door will work but sometimes a little sand can be added if the soil has too much clay. It is clay that causes bricks to crack. Just fool around a bit until an appropriate blend is discovered.

Question: I am a thesis student of Architecture at Auburn University. I am pursuing my thesis in the Rural Studio, which focuses on Green buildings and housing the unfortunate poor of Hale County. Our project is in Lee County, AL, and consists of transitional housing for persons with disabilities. Me and my team are interested in the construction methods of adobe bricks and cast earth. The soils around locally are high in clay content. I was wondering what construction methods would work best in Alabama. As well as would these be viable methods. Any information that you could provide would be greatly appreciated.

Answer (Kelly): I have been aware of and impressed with the work of the Rural Studio and Sambo. I am very sorry to see that he died, but glad that his work will continue. I have much respect for what you are doing. I would say that adobe in particular would be an appropriate material for you to work with. The caste earth really requires the use of heavy equipment and an experienced crew. A few people can make adobe bricks and lay them very inexpensively and create substantial and comfortable housing. I suggest that you see if you can locate a cinva ram press to make the adobe blocks, since it is fast and makes very solid blocks without a lot of drying time and no need for forms. The clay content of the soil needs to be around 20% to 30%, so you might do a little test with some of the soil in a jar of water, shake it and let it all settle for a few hours to see exactly how much clay there is in the soil (the clay will form a layer on top, over the heavier soil particles). You may have to add some sand to the mix. Good luck with your project.

Question: I have spent some time researching earthship homes and was seriously considering that but the research I've done today has me considering adobe. As they seem to be a bit easier perhaps, in construction. Tire pounding would probably be good exercise but I don't know if I'm up to it. Ha! I have 10 acres in the country and plenty of dirt but not sure if it's "the right dirt" or does it matter? Probably just mix with straw? I am curious.

Answer: 30% clay, 70% sand, gravel, decomposed granite makes the perfect brick. As little as 10%clay will also work. Some silt can be tolerated in the mix. Straw is only needed to keep the bricks from cracking if there is more than 30% clay. Too bad Moses didn't know that. Maybe its better. History would have been different.

Question: Aloha. Currently residing in up country Hawaii. Have experience in rammed earth from a former life in Tucson, but am curious about "field" tests for compaction of native soils. There are 5 different bioregions on the island of Maui alone and I am only hand tamping the forms so far. So basically I want to hand tamp local stabilized soils for the purposes of sculpture, not structure. Any thoughts on how to check my available soils before I hand ram something that lacks the desired integrity?

Answer: Small samples. Squash em, kick em, leave em in the rain.

Question: I am busy preparing a business plan to build low cost toilets using earth blocks compressed with 7% cement, do you think I can use those type of blocks to reinforce the pit which will be 2m, do you think the small toilet can collapse after 2 or 3 years because of the daily wet environment, I did not find any information on the internet concerning compressed blocks under wet environment.

Answer: These blocks might work. I am very happy to hear that you would be using them to build the toilets. However, it is known that CEB's sometimes "blossom," another word for expanding, when they get wet. This is because there are a lot of unresolved interior stresses due to the normally ferocious pressure with which the blocks are made. A block that is subject to moisture might be better made with a higher cement content and made with the compression force lowered.

Each and every soil reacts differently to the introduction of cement which is basically not compatible with the clay content. For this reason the book, Soil-Cement, It's Use in Building was developed by the United Nations in 1964 and was used as a handbook for Peace Corps volunteers making bricks around the world. It was prepared and first issued in Spanish by the Inter-American Housing and Planning Center, Pan-American Union, Department of Social Affairs. Later versions in French and English were prepared by the United Nations. In English it is United Natinls Publication Sales Number 64.IV.6. ($1.50). It spends considerable time on figuring cement/soil ratios appropriate to different soils.

Question: I am making stabilized adobe (adding asphalt emulsion) in Todos Santos, B.C.S. Mexico. I want to leave the adobe exposed on the outside and have flat roofs. Will the stabilized adobe hold rain? Do I need to add some sort of water sealant?

Answer: Adobe with about 4% asphalt is quite waterproof. In the USA the asphalt is quite emulsified through chemical magic and mixes easily with water. The asphalt I have seen in Mexico is not as thoroughly emulsified and has a bit of a kerosene smell even after the adobes have cured. It is sometimes referred to as cut asphalt instead of emulsified asphalt. The walls will work well in areas that have rainfall under 50cm annually if you use asphalt in the mortar at the same rate as the adobes. Do not put on an exterior sealant. Many types of sealants have been tried and if they do not breathe, any moisture that gets into the adobe cannot get out and breaks the bond of the sealant at the surface of the adobe. Asphalt will do the job. With your project, you might wish to join our adobe discussion group at: https://groups.yahoo.com/neo/groups/adobe/info

Question: I was wondering how much asphalt emulsion is needed as a ratio to make mud cement and how much does a 50 gallon can of asphalt emulsion cost.

Answer: Each soil will react differently to asphalt emulsion so in New Mexico the definition of a stabilized adobe is a functional definition. That is, an adobe placed on a porous, water saturated surface for seven days may absorb no mare than four percent moisture by weight. Adobe producers will tell people that they use 2 to 10 percent asphalt emulsion but do not mention if that is measured by volume or weight. I find that 8 to 16 liquid ounces is about right to stabilize a cubic foot of my soil's adobe mud. That is about 1/2 to 1% by weight. It is not fully stabilized but will give enough protection to preserve the adobe for my lifetime. Another way to add is to put 5 gallons of emulsion into a 55-gallon drum and fill it the rest of the way with water. That way the water has 10% asphalt. It is a little nicer to work with than full strength emulsion.

The cost of 55 gallons of asphalt had been about $75 until the prices of oil products began to go up the last couple of months. My guess is that it is well over $100 by now. A source of emulsified asphalt in New Mexico is Elf Asphalt on North Edith Street in Albuquerque. Their minimum sale is by the 55 gallon container. You have to have your own barrel hopefully one with a removable top. Plan on splashing some asphalt on the cab of your pickup truck as a badge of honor.

Question: I live in the Pasadena area of southern California and am interested in working with stabilized adobe first in a low retaining wall and perhaps more ambitious projects later. Where can I buy the emulsified asphalt in relatively small quantities (1 gal - 5 gal) locally? Thanks in advance for the help.

Answer: If there is an Elf Asphalt plant anywhere in your area, they may sell you five gallons of emulsified asphalt. There might be some other bulk asphalt plant that supplies road or driveway repair contractors. If not, some formulations of roof asphalt - sometimes called cold process - are emulsified. One just has to read the can to see if it can be thinned with water. A lot of the original work with adding emulsified asphalt to adobes was done in Southern California. Largely a group of retired chemists from Chevron.

Question: I live in Northern California and want to build an outdoor adobe oven. The soil here is fairly organic with lowish clay and sand content. Local construction supply stores give me a blank stare when I ask about availability of adobe type soils.

Answer: Sand and gravel producers usually have something that will work. They might call it crusher fines or crusher trash. Old fashioned base course worked great but at least in New Mexico base course now has less clay and will not clump together. You are looking for a soil that has 30% clay and 70% sand. Gravel particles can be tolerated up to 1- or 1-1/4 inch diameter in adobe bricks. You can use far less clay if you are going to stucco over the horno for weather protection. You can't use much more clay without experiencing cracking. 30/70 also makes a good mortar to stick it the adobes together. For mortar you might find it useful to screen the material through a 3/8- or 1/2-inch screen.

If a sand and gravel producer can't help you, the material is on your property. You just have to dig below that pesky top soil down to sand and clay and gravel strata below. Or find a riverbed or wash nearby. Or make friends with a gravedigger. The Spanish who put the California in California could make adobe bricks most any where in the state.

Question: I am interested in building an adobe exterior wood fired oven for outdoor use in the Boston, Massachusetts area. I cannot find any one who has any knowledge of adobe availability out here and wanted to know what other materials may be suitable to create the shell of the oven specifically the clay component of the mixture, is pottery type clay appropriate or something else that is available in larger size formats?

Answer: A mixture of 30% clay and 70% sand/gravel will work. Sometimes that is called base course at a gravel pit. Pit run or crusher trash will usually also work. We are discussing hornos (adobe ovens) at the moment at http://groups.yahoo.com/group/adobe/. An English style oven was built in MA or ME and was featured on the PBS program the 3000-Mile Garden a few years back.

Question: Are you familiar with liquid glass added to adobe as a stabilizer? If so, where can I get some? I'm building in Terlingua Texas, which is a desert.

Answer: I thought that I had heard everything but this one is new to me. You are near Simone Swan and her adobe dome and vault projects at Presidio. Not to mention Pat with her adobe at the end of Twisted Road at one of the villages between Ter and Pre. I will ask my friends about liquid glass which reminds me that we learned in Science Class that glass was a liquid.

Question: Water glass is probably what she was describing. Sodium silicate?

Answer: My guess is that waterglass without modification will not do the trick. Still no one with actual experience with the material with respect to adobe.

Question: Can Compressed Earth Blocks (CEB) be stabilized in such a way that they can be directly exposed to the weather for use in home-building, retaining walls, driveways, etc.? If so, what is the stabilizer to use, and if not what is the best stabilizer for moisture protection and what other steps must you take to protect the walls?

Answer: Most CEB's are stabilized with cement. There have been problems with exposed walls even with cement. If the walls get wet, some of the pressure of unrelieved stresses at the particle level in the CEB's is released and the bricks "blossom." That's another word for expanding and flaking apart. My own solution would be to stucco exterior wall surfaces of CEB's. CEB practitioners might have more ideas.

Question: I intend to stabilize the adobe with pozzuolana ash like Rice Husk Ash or Silicafume. Do you have any experience on this problem? Please give me some advice! Will I succeed?

Answer: I have never tried this so am unable to predict the outcome. I have always been happy with unstabilized adobes. Just back from Cappadocia in Anatolia where there are 3- to 4-thousand year old adobes without stabilization. They have had constant maintenance even in that low rain climate. However, nearly everything works with adobe so with a little experimenting with ratios, you should get a workable brick.

Question: I live in Barbados where coral dust is available. I am wondering if this can somehow be used in the construction of adobe brick?

Answer: Adobe needs aggregate such as sand, gravel, or stone as the component that gives strength. It also needs something to provide cohesion, namely clay. The coral dust might provide the aggregate part or perhaps it has stickiness and can act as the clay component. I have no experience with coral other than to observe it in some Navajo jewelry along with turquoise. If the coral has no stickiness, then it should act well as an aggregate. You would then need to find a clay source and there should be some in the Barbados. You would only need about 9% of the total weight of the brick. It would not be very waterproof. 30% would be better. I do know that there is some adobe construction in the SE part of Jamaica. If the coral provides the stickiness, then you only have to find lots of sand to add to it to get a great brick. Just try fooling around with the coral dust to see what happens.

Making Adobe Bricks?

Question: What do you know about baked or fired adobe brick?

Answer: Baked or fired adobe brick is found in several parts of the world. I am only familiar with that from Northern Mexico which is imported primarily into Southern Arizona and New Mexico. It is also called "quemado" and is mentioned in the NM adobe addenda to the building code. It plinks when you strike it, it's not damaged by water but it is porous so that if it rains, soaks in, and freezes it spalls or bursts completely. Mostly it is seen as a coping on top of garden walls or sometimes on the parapet walls of homes. Often there is accelerated water erosion on the natural adobe brick course just below the quemado. That is called coving.

Lots of energy is needed to fire the bricks. The Mexican technique is to stack the adobes to be fired and then build a mortarless vault of adobe over them. A flatbed truckload of firewood is ignited at one end and a simple chimney at the other end gets the fire roaring through the adobes for perhaps three days. After cooling the adobes are shipped north. The adobes which formed the vault are then stacked to be the fired adobes in the next cycle.

An interesting observation of this process is that the outer layer of vaulted adobes never vitrify more than the inner quarter-inch if even that. It is only the interior stack that vitrifies. Nader Kahlili has a book on fired houses, but I think that the Mexican experience shows that it would be nearly impossible to do that.

Meantime, the Mexicans have to keep going farther from their villages to find sufficient firewood for the process. The hills become denuded as was the case in Rome. So most folks don't build the entire home of quemados, just the exterior walls or perhaps the above mentioned wall copings.

Add to that the fact that vitrification changes the nature of the adobe bricks ability to transmit heat. It speeds up the thermal diffusivity. That's too bad since it is the sluggishness of adobe that makes it stand out above all other masonry materials as a storage medium for heat especially in the passive solar home.

Question: My house design has a basement. Foundation, stem wall with insulation, then dig basement, use soil for the adobe bricks. Thought it might be easier to purchase bricks if price is reasonable.

Answer: Your idea of making adobes from the basement excavation is excellent. With a little asking around, you might find someone who will make adobes for $.25 to $.40. With a pile of loose dirt, all that is needed is a wheelbarrow, shovel, water, and a form to make four adobes at a time. Once people get the hang of it, two can produce about 500 adobes per day. The secret is not to mix. If the excavated soil is the right blend of clay and sand (30% / 70%) water can be poured into a small area of the pile and when it soaks in, just shovel it into the wheelbarrow. That plus the action of pouring the mud out of the barrow and into the form is all the mixing that is needed. If the soil needs sand or clay, let the excavator machine blend it dry.

Question: Where can I get a hold of a Cinva ram and for how much?

Answer: They are being built somewhere in Africa. Cost and location unknown. We have a Cinva Ram here at Northern Community College in El Rito, NM. Come and try it. It has convinced a number of people to look for a different way to make adobes. I personally think two guys with a loose pile of dirt, a wheelbarrow, a 55-gallon drum of water and a form that makes four adobes at a time can produce adobes faster than a Cinva Ram. Most Cinvas make an adobe about 8 or 10 inches long, 5 inches wide and 5 inches tall. Most codes require a wall at least 10 inches wide so it takes a lot of CR bricks to make a wall. Standard New Mexico adobes are 10x14x4.

Question: I am a 14 year old boy and I live in a rural area. I want to build a small house for "self-sustained" living. I made 16 bricks to start off with and they seem to be drying fine. However I spent forever mixing them. I am very happy to see your suggestion about "not mixing" that will save a lot of work. My main question is this: where I am we have "quack grass" all over the place and it's not perfectly level. Can I just place my form over the mowed grass and start throwing it (the adobe) in, or do I need a tarp to put it on? Thank you very much and my next web stop is the adobe message board which I started out to find!

Answer: You are off on a wonderful enterprise. I was making models of adobe homes when I was 10 and 11. Sometime around age 13 I started making full sized adobes in the back yard. My dad got mad when it killed the grass but after a while he mellowed when he realized that he did not have to mow it any longer! Most any type of construction is hard work, and adobe probably tops the list. But the harder you work at it the more it will mean to you when you are done. Making the adobes is usually the hardest part of adobe homebuilding. Try making your adobes right on top of the quack grass. The first time around the grass embedded in the bottom of the adobes might make it hard to lift the adobes or the bottom might be pulled off. Sooner or later, the grass will quit being a problem if it is one in the beginning. The tarp will make the adobe lift up for sure but they will take longer to dry. A lot of moisture in the adobes is lost downward into the ground. The wicking action of the ground is equal to the drying action of sun and wind at the top. You are invited to join our adobe discussion and support group. We are at: https://groups.yahoo.com/neo/groups/adobe/info.

Question: What are some of the potential disadvantages of using a compressed block machine to make adobes, and how would these blocks handle a warm humid summer like we have here in Wisconsin?

Answer: The blocks should do okay in your climate. Like any wall material, they need to be kept dry after manufacture, as the wall goes up, and for the life of the wall. Since the blocks are made with high compression, sometimes when they get wet, they "blossom" or expand as unresolved internal forces realign themselves. Keep them dry and you will do fine. One reason that just a slurry is used instead of thick mortar is that there would be enough moisture in regular mortar to cause blossoming due to the uptake of the moisture into the blocks. Some blocks have grooves and they go together without any mortar at all.

Something positive could also be said about CEBs like how they provide the same benefits as adobe. CEBs also allow people in wetter climates to produce blocks, and lots of them, because the blocks do not have to dry (which works well in the SW but not as well here). Like any building material, CEBs must be protected from moisture, however, they can be stabilized with Portland or lime. I have had no problem laying CEBs in mortar or a slurry. The only time I have seen the "blossoming" effect is when the blocks were drenched or submerged in water. So, when you say moisture I think it is important to be specific as to moisture as vapor (humidity) or moisture as liquid (rain, snow, broken pipe, etc.)

Question: Where do you find details about making bricks, you said 2 people with a 4 brick mold could make 500 bricks a day. Can you take the mold away as soon as the mud is put in and leveled?

Answer: You just have to fool around with the amount of water in your brick mix to get it stiff enough to stand up when the mold is pulled. And just plastic enough to work it into the mold without too much trouble. Invest an hour or two in fooling around and you will have the right blend for your soil. Also if there is too much clay, the bricks crack. You can experiment with adding sand, small gravel, and some straw to keep it from cracking.

Question: I am seeking a source in central Texas (or anywhere reasonably close) for stabilized adobes. I helped a relative build a small adobe house in Alpine, and saw his own 2000+ sq ft house near Marathon, and an adobe home is the only way for me to go. I don't think I'll ever get the combination of time, materials, and weather required to build my own blocks like my relative did, so a source is desperately wanted!

Answer (Neal): Garten Gerdes in Burnet has equipment (lay down machines et al) but has never produced commercially. The adobe he has made and used on his property is very nice and uses the "fines" from the processing of limestone for road base (also sold and used as agricultural lime). His mix (roughly 70% fines, 30% caliche and 3% AE for stabilization) is very similar to that used at the Adobe Patch in La Luz, NM back in the 70s. It makes a very nice block. The material is readily available since there are rock crushing plants all along IH35 through central Texas. If you want to do it the old fashion way, I'll help you build some forms and get a mix put together. I also know of a form system called the Mold-Master here in Austin that might be available that would be an alternative to regular ladder forms. Not necessarily better, just different. If you only need 2-3k adobes, you could probably knock it out in a summer of weekends or hire some labor to get it done faster. Having a flat space to lay the adobes out and cure them is a necessity too.

Foundations for Adobe?

Question: How do you build foundations for an adobe house (2 floors) on the sand? The location would be on a stable sand dune. I don't know yet if there's any layer of rock at a decent distance from the surface. But, in the case the layer is very deep, what can we do?

Answer: Sand is not such a bad base for a house. The foundation needs to get down to the frost level if there is one at your location. The foundation needs to be a minimum of 8-inches thick and should be at six-inches wider than the wall on each side. For two story construction the first floor needs to be at least 14-inches thick and the second should step back to 10-inches. Adobe walls should not go higher than ten times their thickness so if the wall does not step back for the second floor then it needs to be twenty-inches thick all the way up. My best recommendation is to stick to a single story if you have not built adobe before and given that you are on a sand base.

Question: If one followed the 10 to 1 width/height ratio, could we build a relatively self standing adobe wall (used like a fence) at the heights mentioned? We had learned that if building a cement block wall of over 4 feet tall, one has to reinforce with mortar & rebar. We would also love our 'wall' to have some curves. Thanks for any hints on reading material and whether homemade sun baked adobe bricks would support this wall project.

Answer: It will work just fine. Just stay a bit below the height limitation of a 10" or 12" wall. A good foundation to the frost line or else a Frank Lloyd Wright gravel trench with or without the concrete grade beam will work. Curves in the wall make it stronger. We do have an adobe discussion group at https://groups.yahoo.com/neo/groups/adobe/info. I normally don't recruit for that group but you might benefit from it more than most.

Structural Concerns?

Question: I am working on an old adobe (130+ years) and need to know the maximum height for a 12in. thick wall. Would a poured in place concrete beam help to strengthen the wall.

Answer: Maximum wall height is ten times the wall thickness. That is called the aspect ratio and has been known since biblical times. It is in some codes although many times a code just states that certain brick sizes are suitable for one- or two-story construction. A poured in place concrete bond beam would indeed tie the building together and spread roof loads on the wall. In NM wood bond beams are also allowed and might be easier to do. Three layers of 2" lumber or four layers of 1-1/2" lumber give the required six-inch high by 10-inch wide bond beam. Boards are staggered especially at corners to give interlocking lap joints.

Question: I am an architecture student. I will design a project outside of Phoenix, Arizona, made out of earth. I want to know what is the maximal height for a tower out of earth, and which will be the best structural material if it is not possible to realize one tower (possibly with a rectangular base), only with earth for a height of 20 floors for example.

Answer: The highest existing adobe buildings are in South Yemen. They are seven- to eleven- stories high. The Tower of Babel may have been higher. Adobe has an aspect ratio of 1/10. That is the wall height can be ten times the thickness of the base. To go one-hundred feet high, the wall at the base should be ten-feet thick and should be battered (tapered) to ten or twenty-inches thick at the top. If you built a round tower the total diameter of the tower might be considered as a basis for the aspect ratio and the walls could be thinner allowing for an internal stair or habitation area, but I would not know how to calculate that. Right now the New Mexico building code limits construction to two stories.

Question: I have a friend's home in Carmel CA which was partially built with adobe bricks. We are having a deterioration problem with the walls. One wall acts also as a retaining wall so is subject to constant moisture, the other walls are typical exterior walls. I would appreciate it if you could direct me to some source of maintenance information to deal with this type of problem.

Answer: Ageless Adobe: History and Preservation in Southwestern Architecture by Jerome Iowa, 1985. This history of architecture in the American Southwest presents conservation and preservation of adobe buildings and suggestions for solar options. Photographs and drawings make this a document of unusual value for all interested in preservation, rehabilitation or construction.

Question: I'm looking at building a hybrid adobe/Earth sheltered cabin that would be built half into a hill. If I were to choose this approach, what measures need to be taken to protect the adobe that is bermed, if any?

Answer: Shouldn't build adobe below the finished grade.

Question: What sort of insulation and structural design would you suggest for the ceiling/roof of the structure?

Answer: Heavy timbers/joists lots of straw, twelve inches of dirt.

Question: We are building a home on Bowen Island Canada. We have had to build over an area which is partly fill. It is pretty solid material, and we can remove all organic material, put some rubble in and so forth to stabilize it and prepare for the adobe flooring, but the process is costly. It looks like it may be cheaper to build a standard hanging wood floor with a crawl space, instead of building directly onto the sub-floor as we had planned. We would still like to use the adobe flooring, with radiant pipes in it. What is the experience base of building adobe onto a wood subfloor along with the standard gravel, vapor barrier, insulation etc. Does the very slight give in the wood make adobe untenable?

Answer: Adobe does just fine over wood subfloors. It will take longer to dry due to the required vapor barrier below it and moisture can only move upward. There is no need for gravel. The techniques for the floor would be the same as pouring a concrete floor over a suspended wood floor: it has to be very strong to handle the dead load of the adobe which at three inches thickness will be about 30 to 35 pounds per square foot added to whatever the dead load of the wood system would be.

Question: I purchased a ranch with an adobe roof on one of the buildings. The roof leaks. Without walking on the roof (makes more leaks) is there something I can spray on the roof to retain most, if not all, of the look and seal the leaks?

Answer: Oddly enough, more dirt might help. Sometimes it blows off or washes off in a rain. If walking on it makes things worse, then it could be that the boards underneath have gotten rotten and dirt falls through. In that case, add more dirt carefully. Sometimes we have just had to remove the dirt, replace the boards and then put the dirt back or in worse cases, use modern foam insulation covered by a hot mop roof. Lots of old dirt roofs in the Santa Fe area got a hot mop roof on top. I can't think of any easy fix that can be sprayed on. Asphalt driveways can be sealed with cold process asphalt, also known as emulsified asphalt. It is used also to stabilize adobe bricks. Home Building Suppliers usually have it. I have no experience with it but it might be worth the experiment. Farm ponds are sometimes sealed with a Bentonite clay but I think it has to be continuously wet for the Bentonite to work.

Question: We recently moved to the grasslands of Sonoita, Arizona. We are considering an adobe patio wall, parts of it will be a retaining wall. Is this a problem with adobe, especially if it has some concrete in the block and if I seal it on the earth side of the wall?

Answer: The New Mexico Adobe Code does not allow using adobe below grade. Adobes need to be on a concrete foundation that extends 6- to 8- inches above the finished grade level. Adobes have been used as retaining walls historically and sometimes they last a surprisingly long time. Nevertheless, neither the Code nor I recommend it. Adobe walls have little resistance to lateral forces so if the run of the wall is long and the height of the soil is significant (12-inches or more) the wall would be expected to move before long. There is not much on the market that can truly seal off a wall from moisture.

Question: The person who is helping design the yard suggested the adobe and thought we would have to add rebar for the strength needed. I wondered if drilling the adobe would ultimately weaken it, even if we used some concrete in the adobe mixture. Would that possibly work? Also, we have about 19 inches annual rainfall, so that might present another problem with the longevity of the wall. If adobe is not a realistic option, what would you suggest for a natural looking wall that will blend with the environment?

Answer: (Kelly) You are right that drilling holes through the adobe blocks would either weaken, or more likely actually crack the adobe. I agree with Quentin that this is not a good material for this purpose. My suggestion would be to build the wall with natural stone, either dry stacked or mortared. Dry stacking has the advantage that it will allow the wall to weep water if necessary, so pressure will not build up behind it. It takes some experience to do a good job of stacking stones for a retaining wall, so either read up on it, or find someone with experience to help.

Question: I have exposed viga posts and I have found that these posts are rotting as well. These are vertical. Apparently, the footing was poured too low and now the bottoms of he posts are decayed. The worst one (as far as I can tell - since I can't see into the interior of the posts) has lost about 1 foot of length at the bottom. This has to be replaced, I know. I think I should replace them all after pouring the concrete footer up a little higher - above the brick porch floor so no water ever contacts the posts. I understand there is a metal viga base that can be used to cover the concrete which would otherwise show.

Answer: It would be relatively easy to support the porch on each side of each post with 2x4's or 4x4's while the rotted part of the viga posts are cut off. A sharp carpenter could make a form for a concrete pilar that would come up to the bottom of the intact viga. With a little care the pillar can be designed with a slope on it's top surface all the way around so that any rainwater that hits it will drain off and not puddle up under the viga. The concrete pillar could have beveled edges to make it look neater or it could have flagstone stacked around it to conceal the concrete. In fact the pillar can be built with stacked, mortared flagstone. A rebar from top to bottom of the pillar would be in order.

Question: Do you know of anyone who would be willing/able to do this and do it correctly, in this area?

Answer: I have had the experience of dealing with recently arrived Mexicans who do not present themselves very well but turn out to be spectacular workers and problems solvers. Or you can do pickup truck profiling: 2004 Dodge Diesel Dually: Too expensive, you have to help him make his payment this month. 1976 Ford with the tailpipe dragging and two fenders bent: A bit careless and fly-by-night. 1998 Toyota T-100 with a lumber rack and no more than 30% of the dashboard covered with paperwork: Perfect.

Question and Answer: My husband and I are making an offer to by a 1939 Tudor cottage style home in Phoenix Arizona. The home is made of adobe and has an adobe roof, (Probably clay tile. Adobe roofs are flat and very rare in USA) or so says the agent and the listing information. We like the house and we LOVE the idea of living in an adobe house but how does someone who isn't an expert find out the condition of the adobe both in the structure and the roof? (There is a lot of adobe construction old and new around Tucson. There should be some knowledgeable home inspectors in the area. Sorry to say, I am out of touch with the Tucson scene.) The structure is painted and looks solid but the roof has tiles that look like shingles and are curved upward. They are a whitish color that has black residue perhaps from tree residue or who knows what that is? (Leaf detritus is often the culprit on roofs.) I did a search for adobe roofs...hmmm. There were very few pitched roof adobe houses except in the Tudor revival style but no mention of adobe in the roof. What is you experience with this? (As above) What questions would you ask the seller or even better the inspector to make sure that we are purchasing a sound home with a roof that will last. (I am sure that the roofing material is something that most Tucson area roofers would be familiar with and would be able to evaluate. If you have a good roof and a good foundation, the wall material in between will last forever whether it is adobe, frame, metal or masonry. So check the foundation also.)

Question: I own a thirty year old adobe house with a flat roof and would like to consider putting on a pitched metal roof. The house is a single story on a concrete slab. The walls are adobe and are one brick thick. I know that this is difficult to answer without seeing the home but but do you have any thoughts or advice? Is the weight a problem? Do the parapets need to be removed?

Answer: Should you be in the state of New Mexico, the adobe part of the building code has been recently interpreted to mean that fourteen inch walls are required below if the pitched roof system includes any second floor living space. I got one retrofit accepted on the condition that the pitched roof start right above the vigas on ten-inch adobe walls below. Interpretation and enforcement of the code rules are not consistent. You may be in an area where a permit is not needed. The short answer, then is that you can feel pretty secure in adding a pitched roof to your home. It is a routine addition to homes here in the high country of NM. I would indeed remove the parapet and begin the pitched roof on a wood plate shimmed to level and well nailed or screwed or lagged to the vigas. If you do want attic space we should continue the conversation.

Question: We are replacing the covered porch supports of our Boulder, CO home. We are installing upright vigas and corbels with a cross beam that supports the existing 2x4 rafters. The vigas will sit on the concrete pad of the porch. (We have been planning to hammer drill holes in the concrete for large pegs to go up inside the viga and down into the concrete.) We are trying to figure out attachments - How to attach the corbel to the viga, how to attach the corbel to the cross beam and how to attach the bottom of the viga to the concrete pad. We have looked at pictures and can't see any hardware or obvious means of attachment. How is it done?

Answer: Use a long lag screw that gets six- to eight-inches into the viga. You may want to counter-bore the corbel so that the hex head and washer under the lag screw are not above the corbel. Screw up from the corbel into the cross beam using 6-inch deck screws or timber screws or lag screws. Pick the place where it will show the least and again, counter-boring may be useful. You can counter-bore enough to fill the hole with wood filler or even a wood plug. If you can work from above it will give a neater look to lag from the beam into the corbel. Try to find something to go under the viga post to keep it above the concrete and standing water: flagstone; a metal base such as those made by Simpson Company which specializes in metal connectors and is found at most any builders' supply; or a round poured cement shoulder. Drill into the concrete and epoxy in a piece of rebar that will go eight-inches or more into the viga post. For a 1/2-inch rebar, pre-drill the viga at that diameter. The knurling on the rebar makes it larger and the viga will have to be pounded down onto the rebar. A Simpson 6 x6 post base can be modified to do the entire job but you might have to think up some trim at the base of the viga to hide it. If you are pouring new concrete an anchor bolt and Simpson post base would be easiest. A clever welder could make you a similar unit that was round - for a price. If you cannot drop the elements down from the top and have to shoehorn them into position, it can all be toe-screwed together with those 6" deck screws. Predrilling with a slightly undersized extra long drill bit will allow you to get the screws in just where you want them before the Phillips head screw strips. Counter-boring can make it all look neat. Timber screws are also great, but they have a larger head that is harder to hide. They are hex heads and never break or strip. I use TimberLok brand from OMG FastenMaster. 800-633-3800. It is a pleasure to answer an actual construction question.

Question: I just finished an Adobe floor in Tucson AZ. It is beautiful, but I could use some advice. We laid down an octagonal form made of 2x2's. we leveled the floor and pounded in the adobe. The problem is that the adobe , although packed against the form but not above, had seemed to pull away from the form and the form is "popping up" in a few places. Do you have any suggestions on how to solve the problem. I have thought of re packing the adobe and pre drilling the form and possibly finding some long screws to act as an anchor. Please help.

Answer: The form remains in place? If so there are 6-inch deck screws that might help hold it down depending on what is below it. Several companies also make timber frame connectors up to at least 10-inches if not longer. Where the adobe has pulled away from the form you can pour in a thin slip of adobe mud to fill the space. We just did an adobe floor today and poured it about 5-inches thick. The weather is still cool and we have no idea how long it will take to dry out.

Question: Restoring 100+ yr. old adobe in San Jorge, Nicaragua - the oldest house in the pueblo. The walls were repeatedly patched with concrete, and one side was plastered with concrete. This is a humble farmers house, so the walls are rustic and uneven. Can we replaster with adobe over the concrete patches or must they all be removed (ARRGH!) and replaced with mud. Suggestions to improve plaster adherence?

Answer: Adobe plaster usually sticks very well to cement/lime based plaster or concrete. If not a little wheat paste glue as used by wall paper hanger or made by someone's grandmother on the back of the stove will help. Elmer's white glue or its equivalent can also be used. Sometimes, there is great satisfaction in pulling off concrete and replacing it with adobe mud.

Question: We are purchasing a home in Penasco, New Mexico. It is an adobe home with a pitched roof, very old but in good condition. My husband and I are fixing it up to what we want, so some walls need to come down (old adobe houses are like mazes). But we aren't sure how to take an adobe wall down with out damaging some of the adobe for future use, any suggestions?

Answer: Have to make sure the walls are not holding anything up, like ceilings. It is not terribly difficult to enlarge doorways or windows with bigger lintels or even arches. Some folks remove bearing walls by placing a large beam under the vigas or joists and supporting the beam with posts or masonry columns at the ends and sometimes in the middle. Wear a hardhat.

Question: I'm a construction consultant in Santa Barbara, Calif. and I have the challenge of mitigating water entrapment that appears to be migrating through the walls of a beautiful adobe building here. I found your site through a search engine that pointed me to the article by Quentin Wilson that you have posted. In that article Quentin mentioned a product called Okon W-1 and W2. I thought it might be prudent to talk to him or to yourself and ask if there are any other products that you might recommend for application to the exterior of adobe walls to restrict or inhibit the migration of rainwater.

Answer: This situation can get complicated. If the moisture is seen in the lower portions of the wall, it may be rising from the foundation. Many buildings have had various types of impermeable materials applied to walls only to find that they hold in water that would otherwise be evaporating from the wall surfaces. If it can be determined with certainty that the water source is rain then there are several exterior treatments that can be made. I am not sure if Okon W-1 and -2 are appropriate for exterior surfaces but certainly one of their products should work. One advantage of the W's is that they are essentially invisible. The best product is one that is waterproof to stop incoming rain but vapor permeable so that any moisture that gets into the wall has the opportunity to get back out as water vapor. My recollection is that a permeablility of 5 or 6 perms is desirable. It is not easy to predict the permeability of a field applied material. Usually perm ratings are determined in a laboratory using manufactured building materials. El Rey Stucco in El Paso has a product called Adobe Sealer which they claim has appropriate permeablility. It may now called Crown Seal. The specifications seem the same. http://elrey.com/.

Question: I am purchasing an old adobe place in San Fidel, N.M. that has 3600 sq. ft. of floor with 2000 sq.ft. of it with no roof. All Adobe walls and well worth renovating. One 800 sq. ft. room has for rafters, logs, that have been incorporated into the adobe walls themselves, and the logs have rotted out and need to be replaced. And since money is a problem I was wondering would it be cheaper if I were to remove the logs entirely and go to a more conventional type of rafter or dig the logs out of the wall and just replace them with newer logs? And any suggestions on a sealant for where the logs make contact with the adobe?

Answer: Conventional rafters might well be cheaper as long as they are big enough to hold up the roof load. Usually the logs (vigas) are more likely to be intact in the wall while they rot in the open air of the ceiling system. Lots of the old pueblo and Spanish buildings still have the intact stubs of the vigas in the walls while the rest of the roof system has disappeared. If the original vigas protruded outside the exterior surface of the wall, then that can be a source of moisture and rot. As for treating the new beams or vigas, there is little stuff available that will kill varmints, rot, or bugs that I would want to have inside the house with me. I would consider soaking wood in a solution of Boraxo, 20 Mule Team. It is effective but if it gets wet the Boraxo is washed out. Therefore, protecting the wood from moisture is very important.

Adobe as Plaster?

Question: With my wife, we have recently established a private company in Ethiopia for an investment in eco-cultural lodge in Lake Tana area. As the lodge will be build out of Adobe (similar to some historical construction in Ethiopia), we are considering various construction technique options. Each lodge will be built like a small Ethiopian Orthodox church with wall decorations and paintings. We only use local material (foundations made out of stones, Adobe wall, and thatched roof). The main concern we have in designing is to stabilize the plaster (mud or other material) in order to preserve the wall frescoes we are planning to produce. Do you have any reference on how best to plaster Adobe/mud houses? What material is mostly recommended for interior plastering, keeping in mind that the lodges need to keep a fairly high standard of comfort.

Answer: The same mud that will make adobe bricks makes a good plaster if it is screened through a fine mesh of about 1/8th inch.

Exterior Plastering: the rainy season can be very wet and in order to protect wall frescoes on Adobe, stabilization of mud plastering (or other material) is a main concern.

Good overhangs of the thatch is the first defense. There must be something that locals use. Around here there is mashed up and fermented mixes of cactus and manure. Some folks rely on lime-based plasters.

A book on latex concrete technology has recently been produced (Albert Knott and George Nez, "Latex Concrete Habitat", Canada, 2005). Could Latex concrete or latex slurry be used to stabilize mud plaster?

You can add latex to mud plaster. Careful. If it is so waterproof that it does not breath, then water vapor cannot get out and large chunks of the plaster fall off. Experimentation with appropriate ratios for each soil is required. Make test samples of various ratios and plaster a half-inch thick on a board. Let it dry and set them out to get rained on to see what happens.

Moreover, the municipality of Bahar Dar and Amhara regional state in Ethiopia had very recently (19th of June 2005) agreed to lift a ban on mud house construction in urban areas. Yet, they would like to regulate such construction in order to maintain minimum standard for urban development (they don’t want to see slum types of construction in their cities). Is there any existing standard to which the Municipality and regional government could refer? Bahar Dar enjoys a warm climate with mostly uni-modal rainfall. The wet season can really be wet but it does not last more than 5 months in total.

There are links to the older New Mexico adobe code with an update to the newest code coming soon on www.quentinwilson.com. I think the old one is more appropriate to your location.

Question: Can you make an adobe plaster type mix to cover an old unpainted cement block wall?

Answer: (Kelly) Yes, adobe does adhere pretty well to a cement block wall. Make sure there is enough clay in it to make it sticky, without causing it to crack too much.

Question: Should I mix anything else with the clay, and what is best to seal it so as it won't fall apart with the many changes of weather like rain, wind, dry heat, sun here in the Las Vegas desert climate we have?

Answer: (Kelly) Ideally you want somewhere between 10% and 30% clay, with the rest sand to keep it from shrinking and cracking too much. Sealing it depends partly on how well protected the wall is from the weather by roof eaves. If it is tucked under sufficiently, the straight adobe soil mix will hold up pretty well. Otherwise, you might want to add some Portland cement (maybe 5-10%) to help stabilize it.

Appearance of Adobe?

Question: I wish I could build my own Adobe home. Unfortunately I am just renovating so that I can have the look of Mexican design. Specifically I am looking for information on how to make stucco walls, color washes, and beehive fireplaces. Can you tell me where to go for instructions on how to make my current brick fireplace look like a beehive fireplace? I am wondering if I can simply put something over it to make it look like a beehive fireplace - should I use some mesh and then a stucco mixture. And what typically goes in the mixture.

Answer: I hate to be so smug, but we have dedicated our lives to doing the real thing. Twenty-five years home building and not a one framed. All adobe. The adobe look can apparently be achieved with chunks of foam board covered with various plasters. There are lots of plaster virtuosos in every state.

Question: I was wondering if you could answer my question about a remodel of my brick f/p into an adobe style one. I do need to know if there are special materials on the market (CDN); does it need a 'frame' ie: wire to be fastened onto the existing brick or is there some kind of stucco/masonry, etc. materials that I could improvise with? I want to eliminate the sharp angles and replace/remodel them into a more rounded (pleasing) shape.

Answer: Use expanded, galvanized metal lath to form the curved shaped. Standard gypsum based plasters will cover the lath and give the desired shape. As long as their are few air voids behind the lath, the fireplace facade will be very strong.

Question: What can I add to my mud to give it that dark brown "wet look"?

Answer: Several coats of boiled linseed oil. Apply it with brush, roller, or rag to an adobe surface once it has dried. Remove anything still on the surface after 20 minutes or it will turn gummy. We have used various oil based varnishes if the linseed does not impart enough dark brown color. Some folks even apply a layer of polyurethane or a clear varnish on top of it all. Every dirt works up differently so you get to experiment a bit to find out what works to get the result you want with yours.

Question: I have a small mobile home. I want to do an adobe siding. Can this be done and how would I go about it . I don't want to do bricks. I don't know if siding is the right word but I want it to look adobe.

Answer: Paint it brown.

Question: We just bought a home in Southern Utah. The upstairs room's walls are adobe. We are trying to remodel and make this room suitable for our young children. It looks like someone has wallpapered at least 3 times. How can we finish these walls. The adobe is coming down, the wallpaper is cracking, and the plaster is falling. Is there a certain kind of paint to use, cement? What? We can't leave the walls bare.

Answer: Wow! Sounds like a real mess. If the plaster is coming off the walls, I think you will just have to remove it. Once removed, the wall can be plastered again with adobe plaster if that is what was used before or a gypsum based plaster such as Red Top which is mixed with three parts of sand or Structolite which is used right out of the bag with water. Anywhere the wall is in good enough condition to be mostly solid, you can paint over the wallpaper, mud plaster over it or Structolite over it. If you choose to paint and if there are ridges left by the wallpaper, you can smooth that up with a big wide sheetrocker's taping knife and a bit of joint compound. If you are really, really lucky you might be able to make chunks of falling plaster stick in place with Gorilla glue which is a urethane based product that has proven to be pretty amazing. This is just a guess and you might be the first person to try it but you could get your name in Reader's Digest if it works.

Question: I am in the process of purchasing an adobe brick home. The bricks in the home have been painted over, home was built in 1960, and may have several layers of paint. How do you remove paint from the bricks? Is the only manner to remove the paint, sandblasting? Will this process damage the bricks? The inside of the home has also been painted, however we will most likely Sheetrock. Do you have any suggestions for ensuring this process is done appropriately in order to prevent mildew?

Answer: I have never tried sandblasting on adobe. It might work but it might take a lot of the adobe with it. Never heard of anyone else doing it either. Might just have to find a strong scraping tool and tackle it by hand. Sheetrock? Why buy an adobe house in the first place? It totally ruins adobe walls' thermal characteristics to have an interior surface that is not in thermal contact with the adobe. With Sheetrock there will be an airspace to accommodate the presumed furring. That airspace is also another opportunity for those little mildew or even mildew critters to get a start in life. And that interior paint may act as a a vapor moisture barrier to keep the adobe wall from breathing. If you do use Sheetrock, rough up the interior paint in as many places as you can to break the moisture barrier.

Question: My husband and I are about to purchase an adobe home that was completed in about 1989. It seems both the interior and exterior walls were later painted with standard house paint. We very much would like to remove this, and revert to the original natural finish. Any clue how this can be done?

Answer: Sometimes if you just dampen the wall the paint will fall off or can be easily scrapped off. I have a three head mister from a plant nursery that works nicely to apply moisture at a fine, controllable rate. Spray it until it begins to run then move on. Go back over the wall again and perhaps a third time. Then, good luck. It may be very easy or it may take a lot of work. We got fooled by wallpaper that was on an adobe wall once. We thought it would come off so easily. It took a lot of work. The wallpaper hangers past had penetrated well into the wall and the created a strong composite surface. Quentin Wilson, not the rocket science boy from the movie.

Question: We have built (still building, actually, but we live there) an adobe home in SW Colorado. We are using Structolite plaster on most of the interior walls but we have several that we want to leave exposed. What do you recommend for a finish on those that will keep them as natural looking as possible but keep them from "dusting"? How would you go about applying such a finish?

Answer: Exposed adobes can be washed and smoothed a bit with a sheepskin, a towel, a rubber float from the plastering trades or even left as is for a crisper look. Actually the wall is usually fine with no finish and visitors just have to be reminded not to rub the walls. It they rubbed painted Sheetrock walls over a year old, they get chalk on their hands. There is a clear finish that waterproofs the wall yet allows it to breath. It is OKON and comes in two formulations, W-1 and W-2. I can never remember which is which but don't need to. A competent paint company that carries it will have employees who can advise. (Home Depot and such outfits may not.)

Question: My husband and I purchased an adobe block home that was built in 1978. The exterior walls have been painted off white which is in poor condition (i.e. peeling). Is it possible to restore adobe walls to their original appearance after they have been painted? Soft red brick peeks through some parts of the peeling paint. Any suggestions?

Answer: Probably just simple, backbreaking, brutal, hard work. Paint scrapers with changeable blades, the type with a long handle so you can get two hands on them will work. Sometimes, if you are lucky a stiff wire brush or even a bristle floor brush. Or try spraying the wall with a mist of water and then see if the paint rubs of easier. A steamer can be rented in some places that is used to steam off wallpaper. That might work. Maybe the fact that it is already peeling means that the job will not be as difficult as I may have led you to believe.

Adobe as Mass?

Question: I am involved in the design for a passive solar home in Maryland. We are investigating materials to use for interior thermal wall mass, and adobe seems like an excellent choice.

Answer: Adobe would indeed be a good choice. Besides the fact that it has a specific heat of 0.2 which is the same as concrete, stone, brick and some concrete blocks, adobe has a wonderful coefficient of heat diffusivity which results in its releasing heat more slowly that the other materials which all have higher diffusivity.

Question: There seems to be some discrepancy as to whether adobe is an effective insulator. Adobe is a tremendous capacitor of heat. Can you clarify this for me?

Answer: In non-steady state situations - such as our planet - capacity mimics insulation. Insulation cannot mimic capacity. Some sources cite it as a good thermal mass, but poor insulator.

Question: I’m a grad student currently working on modeling the energy efficiency of a passive-solar adobe home. I been having a lot of trouble trying to find the physical properties of adobe, thermal conductivity, absorptance and specific heat. Can you guide me on this matter? I would really like to find a reliable (quotable) source for these parameters.

Answer: Specific Heat: 0.20 BTU/DEG F/LB Source: Passive Solar Home Book by Edward Mazria, Rodale Press about 1982, out of print but in many libraries and at amazon.com. Absorptance depends on the color of the wall presented to the sun and varies incredibly from light to dark colors. Source: New Mexico Energy Conservation Code Applications Manual available from the State of New Mexico Construction Industries Division, 725 St Michaels Drive, Santa Fe, 87501

Thermal Conductivity, BTU/SQ FT/DELTA T/HR also known as or related to thermal diffusivity, rho, has never been determined as far as I know. It is the most important number and its value, whatever it is, is what makes adobe the planet's best passive solar storage medium. Rho is less than concrete, stone, brick, and concrete block so it does not lose its heat as fast as those materials which have nearly the same specific heats. Its rho-value is higher than wood or paper which are so low that they are very slow to transfer their stored heat even though they also have nearly the same specific heat. The paper I refer to is in the form of books or other tightly packed forms of paper. Mazria hints at this relative conductivity in a table of appropriate wall thicknesses for Trombe Walls. A person might use Mazria's table and extrapolate for adobe if the numbers can be found for the other building materials. Ed Mazria, himself, is a well-known architect practicing in Santa Fe. He might respond to a well structured question requiring a short answer.

Sometimes, Thermal Conductivity or its reciprocal, Thermal Resistance is quoted from determinations made by standard laboratory calorimeter tests at steady state. As soon as steady state is mentioned, the results should be thrown out. The planet is not steady state. The sun comes up and goes down, the air cools off and warms up. The NM Energy Code Applications Manual hints at these planetary truths in the several tables that give Effective U-Values for adobe walls depending upon: Climatic Zone in NM, Orientation of the wall (n,s,e,w) Color of wall (light, medium, dark).

The State of NM got its numbers from computer simulations run in the mid-1970's. Along with that, four adobe buildings and buildings of several other types of materials were built at the Tesuque Pueblo Solar Thermal Project at the same time. Real data points measured on the buildings confirmed the millions of bits of information produced by the computer simulations to convince the researchers at the University of New Mexico to publish the tables of Effective U-Values in the Manual.

Question: I am trying to find the R-value of 9" thick adobe brick. I live 12 miles from Oklahoma in Texas, 75 miles north east of Dallas. I do a/c for a living and need to figure a heat load on two houses.

Answer: That's a mighty tough question. Adobe has about 140 Effective U-Values according to the NM Energy Conservation Code Applications Manual. I am looking at Zone 9 which is Clovis and Roswell which is as close to the Dallas area as we are going to get minus some of the humidity. For a Medium Colored Wall the U-Values are North: 0.227; East: 0.198; South: 0.160: West: 0.204 For dark colored walls the values go down 10 to 30%. For light colored walls the values go up 8 to 15%. The ASHRAE Steady State U-Value is 0.263. Those numbers are for 10-inch thick adobe walls.

R-factor is the reciprocal of U-Value ( R = 1/U ). Because adobe is a storage device rather than a resistance device it generally performs well beyond predictions based on steady state numbers. The NM numbers are based on the Tesuque Thermal Study Project of the 1970's which used full-sized adobe test cells and computer numbers to mimic adobe's dynamic performance. I do know that there was an entire school district built in the Dallas area with adobe in the 1930's.

Question: I would like to build a home with some adobe walls. One of the walls I would like to be adobe would be on the south side of the home but would also be between the living space and an attached greenhouse. I still need to explore the attached greenhouse option, but would you recommend adobe in this application? I am concerned about the higher humidity levels. Are there any changes you would suggest - i.e. a vapor barrier between the stucco and adobe?

Answer: This is a perfect use of adobe. It stores the excess heat of the greenhouse and conducts it to the interior of the home. The elevated humidity will not hurt the adobe one bit. Adobes achieve their maximum strength at 60% humidity. They also have a great ability to soak up moisture and return it as the atmosphere inside dries out. We are starting to see some papers to this effect at our yearly Adobe Conferences here in El Rito. May 20-22 in 2005. The Germans have long been aware of adobe's moisture modulating capabilities and Gernot Minke has a chapter in his Handbook of Earthen Construction.

If the adobe wall is between the living space and the greenhouse, you can save money by omitting stucco. Exposed adobes, a mud wash or mud plaster will work fine. Try to find a light color to avoid having to paint the wall. Paints are less breathable than is desirable in this situation.

Question: Do you know of any instances where this type of setup was used as a significant portion of heating a residence? I was looking to use the thermal mass and attached sunspace as a means of heating the conditioned space and also tempering the thermal conditions in the greenhouse. I have heard rumors that this can be effective in both these goals.

Answer: (Kelly) Yes, Quentin suggests that this is a good strategy, and I agree. I know of one home where an adobe Trombe wall has been used quite effectively in heating the home during the winter in New Mexico.

Education?

Question: I'm building an adobe art gallery, 20'x18'. The bricks are stabilized 7adobe dirt / 1sand / 1/2 cement, and they are very durable bricks. My location is a beautiful tract of land near Big Bend Nat'l Park, with a great view of the park. I've put up one course of adobes, and was thinking about putting on a workshop for putting up walls. How do I go about promoting this project?

Answer: Simone Swan hosts a workshop at her home in Presidio to demonstrate mud plastering. She has a talent for gathering people from great distances. I lack that talent. I do lots of classes on adobe construction but we usually just tackle a short wall and corner or intersection. We mostly spend our time demonstrating the several ways of putting up masonry walls and the fastest methods we know. Then I turn students loose to pursue their own projects. If they are nearby we go visit them as they progress and offer suggestions when appropriate. To get a building built that you own, you begin with students who have a slight if unspoken reserve that they are contributing to someone else's ultimate new worth. If you are 80 years old, widowed, blind or in a wheelchair they are less inclined to think like that. It also helps if there is some expertise to be shared with participants. That expertise usually comes somewhere around the third structure. There are some folks at Blue Rock Station in Ohio who seem unintimidated by their short term experience and have opened their first project to hundreds of children and thousands of adults to demonstrate alternative building systems - www.bluerockstation.com . Their website might offer insight into how they attract the multitudes.

Response: Thank you for your suggestion. I do know Simone's buildings. I've had some experience in adobe building, as you may see my work in the picture. A group is good, because its easier with multiple people, and they don't have to work so hard, and can learn so much. The fact that my building is an art gallery, they also will be able to revisit it, and show their friends something they worked on. I followed your web site recommendation to use cement as a mortar between the stabilized blocks. Here you see that I am attempting to get an old adobe look. And I do not plan to plaster over them.

Answer: After reviewing my response with my class, it was suggested that a good old-fashioned barn raising like the Amish, Presbyterians, Spanish, Farmers, Mennonites, Homesteaders, Baptists, Sinners, Seventh Day Adventists, Neighborhood Associations used to do. Actually, the Seventh Day Adventists still do it and people gather from all around to put up a new church. Perhaps Terlinguans would gather around a project for the sake of seeing a neighbor get a structure up.

Miscellaneous?

Question: My husband and I own 5 acres up in the Uintahs. We have been talking about building a cabin for ages, but just today, when seeing an Arizona hacienda on TV, we both jumped up and said "that's it!" Our land has an abundance of red dirt (clay?) My husband is a cement finisher, so that will help. Next step - what kind of foundation? Do the bricks need to be baked, or just air-dried? Can you refer us to some how-to books? How do you do rough-in plumbing, septic tanks, etc. Thanks.

Answer: Whew, Georgia's question is more a request for a text on homesteading! She might want to join our adobe discussion and owner/builder support group at https://groups.yahoo.com/neo/groups/adobe/info. Might be clay. Usually the red dirts have silt in them too. Just have to make some test bricks to see if it works. Lots of times, adding sand to the soil gives a good brick. Standard concrete footing down to the frost line with a stem wall that gets 6-8 inches above the exterior finish grade. The stem wall needs to be the width of the adobe brick and the footing should be 4-8 inches wider than that. Air dried, sun cured. Adobe build it yourself, by P.G. McHenry, Jr. University of Arizona Press about $25.00. Lots of books out there on plumbing. For septic tanks, start with the state to see what the regulations are. As for etc, we are just now writing that handbook. PS Northern NM Community College here in El Rito has the Department of Southwest Construction. We are teaching homebuilders in two semesters. (one in a pinch)

Question: We have a contact in Quebec who built a home out of straw, clay, lime sand and rockwool. Blocks 4'x4'x1' are 5 lbs. Had an article in Harrowsmith April 1996. EXCITING , AND IN-EXPENSIVE (WELL, 65K , Canadian, FOR THE COMPLETED HOME OF 2000 SF) However, we are having trouble really getting some facts about the veracity and soundness of using the product. Anything similar come to mind?

Answer: (Kelly) One approach to making adobe blocks is with a Cinva Ram press, which is described on this page. I have a friend in New Mexico who used one to make a house over ten years ago that is very comfortable and durable. It cost him under $1,000 and about a year's time. There is an interview with him in the Sampler of Alternative Homes video. Many places do allow construction with adobe, and there are several books that describe how to proceed.

Question: I have been trying to find out more information on concrete homes. How practical are they, how green are they? How do they differ from adobe in durability and sustainability?

Answer: (Kelly) In general, concrete is not a very green material, for several reasons: 1) A tremendous amount of carbon dioxide (greenhouse gas) is released into the atmosphere during its manufacture. 2) A lot of transportation of materials is involved in both the manufacturing process, and then getting the cement to its final destination. 3) Concrete also must be reinforced with steel, which has its own environmental consequences.

Adobe, on the other hand, is much more environmentally benign. It is basically earth, which can often be obtained on the building site. All you need to make adobe blocks is some clay, sand, straw and water. In some instances a small amount of cement or asphalt emulsion can be added to the adobe, to "stabilize" it in circumstances where it is subject to direct weather. Generally adobe walls are protected with substantial eaves and foundations.

Question: I live in England and am about to buy a house that is in a poor state of repair. The bathroom is located under the stairs and is very cramped - if you wanted to sit in the bath away from the tap end you'd hit your head on the recess! I saw a style of bathroom I liked whilst looking at earthships. The bath was formed from what appeared to be adobe, with some sort of glaze inside it to make it smooth. Would adobe be suitable for this? Do I have to cover it with a sealant to stop it absorbing water and can you paint it after it has set? I'm looking to make a deep, round bath - that won't have to be long so I won't hit my head! Whilst I appreciate that in still owning a conventional house I'm missing the point entirely of what earthships stand for, I would still like to use natural materials. I hope this question doesn't sound too silly!

Answer: I love adobe more than most anyone. However, an adobe bathtub is a very bad idea for the same reason that a stone, tile, or concrete tub is terrible. The masonry requires too much heat to warm up and robs the heat from the water. Only rich folks who don't care how much heat they waste should have such tubs. Most masonry materials have a specific heat of about 0.2 BTUS/Degree Fahrenheit/pound. Cast iron of which many tubs are made has a Sp Ht of about 0.05 and the metal shell of the tub is relatively thin so not that much heat is lost to the metal. However, think about sitting back against the back of the metal tub as the water fills on a cold day. It takes a real man or woman. Multiply that by twenty to get the heat robbing effect of adobe. But cheer up. That is why adobe is the world's number one heat storage device in passive solar homes.

Question: I would like to know where I can find affordable house plans/blueprints for having an adobe home built.

Answer: "Adobe Homes for Today, Flexible..." Laura and Alex Sanchez and "The Small Adobe House" Agnesa Reeve.

Question: This is going to be a silly question. Do you know where I might be able to purchase a miniature version of an adobe house. I ran across 1 here in Philadelphia, at a thrift shop, but I couldn't buy it - it didn't have a price tag on it. When I came back for it the next day - it was gone. If you know where I can buy 1, please let me know.

Answer: Someone was selling them through the New Mexico Magazine not long ago. They can be found in various gift and art shops in Santa Fe and Taos. Time for a visit to NM.

Question: I want to avoid the use of plastics at all costs (which rules out a polyeth barrier) and I was thinking maybe a wax coating would help as a moisture barrier.

Answer: Might work. Try it and report back. You will be the first.

Question: Hi, I'm not sure if you are the correct expert since my question is not specifically about adobe, but about the vigas which usually go with adobe homes. I live in Las Cruces, NM in an adobe home with wood vigas. These vigas have badly deteriorated due to both sun (vertical and horizontal exposures) and water (primarily the horizontal exposures). I am about to apply some sort of protectant to this wood and need advice on what product to use (the wood was previously stained) and what process to follow. I'd like to find a product with at least a 15-year guarantee.

Answer: Welcome to New Mexico, the skin cancer capitol of the USA. Cheer up, Argentina has a worse problem than us since they are close to the big ozone hole in the Southern Hemisphere. Basically, the wonderful, sunny days of Southern New Mexico carry a huge dose of ultraviolet that just boils away anything chemical. I have an interest in boats and lots of paint companies specializing in marine paints/varnishes brag how long their products hold up in the Florida sun or the Sea of Cortez. Those same paints/varnishes used on boats in NM are gone in a year or two. About the only things that hold up to the sun are metals, glass, stucco and the vertical surfaces of timbers. The best protection for wood is the wood itself as it ages. That means that about 1/4 of an inch gets eaten up but then the wood stabilizes. One-inch trim on New Mexico houses disappears while two-inch trim erodes but gets stable at about 1-1/2 inch. The problem with vigas is that most species of trees develop splits and some species twist as they age. If the splits occur on the top of the viga, then the water just moves on down into the viga and lengthwise, too. Often the water is conducted to the interior of the adobe wall or in your case elsewhere along the viga. Some very impermeable products used on wood can backfire. Once some small pinhole develops, moisture gets in and then cannot easily get out resulting in accelerated rotting or the impermeable coating falling off in chunks as its bond to the wood is broken.

Question: Some of the horizontally exposed wood is so badly deteriorated that I am applying epoxy wood rebuilder to the top (exposed) portion of the viga, which crumbled away about halfway down (this applies to only about a 3-4' section of the total 24' length because this particular section was exposed while the rest was not). These are vigas which are structural for the porch roof but where the original design left an opening for a planter and had the vigas continuing through the opening. The frame around the opening was poorly done and caused water damage to the vigas as well as poor maintenance causing sun damage. Is this okay?

Answer: It is not. If there is no visible sagging of the roof, you are probably okay but something needs to be done to stop further deterioration It's that or replace the viga. Probably not necessary, but if it comes to that, it is not always as difficult as you might imagine.

Question: Mostly, I need advice on the best product to protect all the remaining wood (vigas, wood windows, etc.) from sun damage, which will last as long as possible!

Answer: I am working on a photo essay on the evolution of canales in and around Taos where the animal has gone through the most change. When that is done, I will start a photo essay on the evolution of exposed vigas. There are two solutions that work. One is to cut off exposed vigas, chisel out the first inch or so into the wall and then stucco over the hole. I have done this myself on several houses. In an extreme case, the School for the Deaf in Santa Fe, steel pipes of different diameters with welded on hatchet marks on the ends were welded to plates which were then bolted to the wall where the wood vigas had been. You can see them if you visit Santa Fe. The other solution is to build a metal cap over the top half of the vigas. They are galvanized metal, vinyl coated metal such as Pro Panel, or in the most wonderful form, copper. Copper in about 26 to 31 gauge thickness is not too expensive and you can work it yourself including soldering on a flange where the viga meets the wall to form a vertical flashing. These caps can be seen in Santa Fe and all over Taos where they have risen to high art with lacy cutouts and other decorations along their lower edges. The important thing about the caps is that they should be nailed or screwed to the vigas on the sides, not on top and the fit should be less than snug without the application of caulk or roof tar. This allows air to circulate and moisture an opportunity to leave when it does sneak in. That is just as important to the metal as it is to the viga so the former won't rust while the latter doesn't rot. Properly detailed, this will give you a 22-year fix. It should work also for your vigas in the planter opening.

Question: I am searching for home plans for a large family. We hope to build with adobe, passive solar. We live in Arizona and feel sure it would be criminal to deny the sun an opportunity to serve our home. We are not wealthy, and cannot afford to custom design with an architect. We need at least 5 bedrooms. Is there anyone out there selling stock plans of this size? Any information you have would be greatly appreciated.

Answer: Laura and Alex Sanchez have a book, Adobe Homes for Today. It costs about $25 and has plans for a number of adobe homes, most with a solar feature. From the book you can order plans on a CD at again about $25 per design. With AutoCad you can modify the plans before printing them. Some of the plans allow for future expansion and many allow trimming the house out in three styles. How you are going to handle the solar aspect is highly dependent on your location in AZ as a house that would do well in Flagstaff will bomb out in Yuma.

Question: I plan on building a small (+/- 1800 sf) home in Glenwood, NM in the next couple of years. It's in the early planning stages now. I am considering an adobe home. Have you seen any cost comparisons of adobe construction vs. stick framed construction.

Answer: The best information on cost comparisons is from Vishu Magee at Archetype Design: http://www.archetype-design.com/. Usually a good frame builder can get a building up more cheaply than an adobe building. But the cost difference should not be too great insofar as the cost of walls is usually only 7 to 11% of the total construction budget. What usually runs the cost of an adobe home up is all the other choices that owners make for premium items in the other budget line items. Often, for instance, the cost of interior plaster is equal to or greater than the cost of the adobe walls. The solution is to omit plaster and have exposed or lightly mud washed walls which can easily be painted. The list goes on.

Question: I currently live in an adobe brick home that has mold and mildew growing on the inside walls. Can this be successfully and completely removed? How? There is no active heating system in the house presently, the roof leaks (soon to be fixed), and there is plaster for the ceilings which also have mold. My concern is can this be stopped and completely eliminated? Will the process pose a danger to the structure? The bricks are painted white inside, natural outside. I am unsure of the type of paint used.

Answer: Sounds as if you have a major case of moisture incursion into the home, probably from the roof leak. If the house is not heated, that further favors the mold and mildew. Hopefully the house is on a proper foundation that rises six- or eight-inches above the outside ground level. Sometimes moisture can creep up a foundation through capillary action and into the adobe walls. A moisture barrier on top of the foundation would have stopped this. If no barrier, and moisture does move up from the foundation, it rarely goes much higher than a foot in an adobe wall since adobe does not support capillary action as well as concrete. If you can get the house dried out mold and mildew go away. I myself don't worry about M and M nearly as much as modern alarmists do. In some cases M and M is a reason to call in the environmental remediation squads to deal with it. I don't know if you should believe them or me. I spent years crawling around in, on and under houses and I survived most likely out of pure ignorance of any danger.

Once the moisture source is found and stopped, you can go over walls and ceilings with a solution of one Clorox in ten water. A stiff cleaning brush or sponge should do the trick. A second pass with a solution of one pound 20-Mule Team Borax in two quarts water painted on the wall will soak in a bit if the paint is not too thick and suppress future spore development. If there is a cavity above the ceiling, there may be more M and M there to deal with and there could be damaged insulation.The Clorox/Borax process will not harm the structure but it might not be thorough enough to please a thorough-going remediationist. The problem is not the fault of the adobe walls. When there is moisture and cool conditions, most any wall becomes a haven for M and M.

Question: Any suggestions on sealants, preferably local, for brick floors and exposed adobe walls? Albuquerque area.

Answer: Boiled linseed oil for floors. Okon W-1 or W-2 for walls can be gotten from Wellborn, now Dunn Edwards Paints. The counter men in Santa Fe, at least, can tell you the right choice between 1 and 2 (888-337-2468). Exposed walls can be washed with a terrycloth or sheepskin to consolidate and soften the surface well enough so that no chemicals are needed. Even painted Sheetrock walls will dust after several years.

Question: I have just replaced a 265-foot adobe brick wall and have all the whole bricks neatly stacked on pallets to prove it! I live in Las Cruces, NM in a rammed-earth house 12 years old same as the now dismantled adobe wall. Is there any value to these bricks I should be aware of? Can I build small walls, bancos and end up with a smooth hard-plastered surface suitable for sitting on?

Answer: Bricks should be worth between 50 and 60 cents each sitting on the pallet. They can be used to build anything normally built of adobe. I built several houses of salvaged adobes. They recycle nicely and can certainly be plastered smooth and hard for interior or exterior use. Outside they need a good foundation.

Question: I am looking to build an outdoor patio area in SW Texas, including a fire pit, BBQ, and wood-fired brick oven, all finished or made from adobe. I want to also build simple adobe walls to enclose the area on 3 sides for some privacy. Can you provide me with some reference materials for such a project, particularly the fire pit, BBQ, and brick oven adobe structures? There are countless books on building houses, but I can't find material for outdoor living structures.

Answer: PG McHenry's books are the best references. "Adobe Build It Yourself", and "Adobe and Rammed Earth Buildings. "Sunset Magazine" once had a series of books on outdoor structures. None was for adobe in particular, but several were for masonry in general. There is an adobe brick oven monograph somewhere out there on the Internet.

Question: My husband and I are buying an owner built Adobe home with brick flooring in southern Arizona. The few things that I know about the home are: the brick flooring has radiant heat, the inside adobe walls have been painted white, there is a membrane roof on the structure. We know nothing about Adobe. How do we know if we are getting a quality well made adobe home? How do we find an inspector that knows Adobe?

Answer: Arizona has seen significant adobe construction in the past couple of decades. There should be some very knowledgeable home inspectors in Southern Arizona who understand adobe. If banks or real estate folks can't give you a referral, try Bob Barnes at Old Pueblo Adobe in Tucson. He should know people.

Question: We are installing an adobe floor on a house in Huntington VT and are wondering about green products used for sealing adobe floors?

Answer: Boiled linseed oil is my choice. Put on one or two coats without thinning to load up the pores. After 20 minutes wipe up any oil on the surface or it will become gummy. A day between coats is good. Thin the following coat or two 50% or less with turpentine or citric oil thinner to help make sure that the linseed oil hardens. It's an oxidation reaction. Again, mop up any residue on the surface after 20 minutes. Linseed is the hero of all the firefighter training movies because it combusts spontaneously better than anything else. So put any rags in a sealed container or in a bucket of water.