The Owner-built Adobe House

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Though the technique of adobe brick construction developed in the desert Southwest, a growing number of do-it-yourselfers are finding it to be a satisfying and economical way to build in almost any climate. In a new book — which should be available through Charles Scribner's Sons by the time you read this — author/builder Duane Newcomb clearly describes how he put together an adobe lime that's now valued at $130,000 . . . for only $20,000! We were impressed enough by the manuscript of the instructive volume to obtain the right to excerpt Chapters Three and Five —"Making Adobe Bricks" and "Putting Up Adobe Walls" — in this, and in the next, issue of MOTHER.

CHAPTER THREE: MAKING ADOBE BRICKS

Text and illustrations from The Owner-Built Adobe House by Duane Newcomb, copyright © 1980 by the author.
Reprinted with the permission of the author.

Modern adobe bricks consist of a mixture of clay, sand, straw, and emulsified asphalt.

Clay holds your bricks together just like the cement in a concrete block. It contains primarily an aluminum salt and is made up of extremely fine particles. There are several different kinds of clay, but you can use any one of them for making bricks. The so-called adobe soil of the Southwest actually contains too much clay to produce good bricks. What you need is a sandy clay or a clay loam. Soil with too much clay produces too many shrinkage cracks. Soil that is too sandy crumbles easily. If, after a soil test (see Fig. 1), you find that your ground has too much or too little clay, you can bring in sand or soil with a higher clay content as needed.

Sand, the second ingredient used in making adobe bricks, actually is an inert filler held together by clay, much like gravel in concrete. You can use almost any type of sand in making bricks except beach sand, which contains too much salt. Add extra sand to your soil only when you need to lower the clay content to meet code requirements.

Straw, the third ingredient, doesn't add strength but binds a brick together and allows it to shrink without cracking.

Emulsified asphalt (a petroleum residue utilized in paving) makes the bricks water-resistant. In ancient days the Babylonians succeeded in making waterproof brick, but the art was lost for centuries . . . to be rediscovered about fifty years ago. Without the addition of emulsified asphalt, unprotected bricks soon weather away . . . with it, the bricks stand for many years without appreciable damage.

In New Mexico and nearby areas where the bricks are to be plastered over and not exposed to the weather, they are generally left unstabilized (not treated with emulsified asphalt). Adobe-makers create the bricks as people have been doing for centuries and simply lay them up into walls with a mud mortar. You can do this where the codes approve. Bricks exposed directly to the weather must be treated.