SouthWest Solar Adobe School

Hands-On Adobe Instruction

OR
What We Did On Our Trip to Arizona



 
 
 

The Source
An Open pit mine yields clay, sand, gravel, and even large aggregate laid down in ages past on this alluvial plain.
 

The soil is transported to the mixing station where a small percentage of asphalt emulsion is added.  The pug mill combines the ingredients and dumps the finished mud out on the storage surface. 

The "lay down" machine is a self-propelled hydraulic unit that carries a supply of water, mud and the adobe forms.

The forms are visible in the center part of the machine.







 
The fresh adobe blocks are laid on a prepared bed of earth.  After a day or two they will be turned on edge and hand trimmed.  Each block is handled only three times during its transition from mud to structure. 
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 A good wall starts with a good foundation.  This stem wall is as wide as the finished wall and must place the first course of adobe block at least 4" (some codes may require more) above the grade.
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 		 The first bed joint must make up for any unevenness in the stem wall.  This stem wall tapered down on each end. 
The mud is a bit thicker there in order to bring the top of the first course of block up to level.  The "Speed Lead" or "Story Pole" and level string are all visible at the left end of the stem wall.
SWSA School Instructor Joe Tibbets gives pointers on keeping construction level.





 

 Joe Shows the class how to tie two intersecting walls together.  This short wall will end up as a tapered buttress that "stair-steps" up to the main wall.

 


 

 A minor error gets corrected as the second course begins.  There should be an overlap of at least 4" above each joint.  This block is being moved 1/2 span to the right.  A half-block will be placed at the far left end of the course.

 

"Let the games begin..."  The class got a little livelier as Joe showed the "proper" way to  pass Mud on an adobe project. 
 
Electrical boxes are set into notches cut into the block.  Some codes allow direct burial of the wiring in the mud joint.  Others require conduit.

Electrical boxes should be chosen carefully.  They need to be deep enough to allow the electrician enough room to work and durable enough to stand up as long as the wall lasts.  Since some adobe structures are hundreds of years old it would be wise to consider something in metal.

An old rake, flattened and sharpened, then welded to a piece of 1" water pipe makes a great adobe saw.  The hatchet on the top of the wall is another favorite block trimmer.  Cutouts for electrical boxes or blocks less than full size can be created with these tools.
 
A plaster "key" is inserted into the wet mud to demonstrate how to prepare the wall for an optional plaster coating.

Blocks are "placed" on the wall, NOT dropped or slid.  Once in the mortar, they are twisted slightly as they are worked down to the string level.

 

Arches are laid up over a wooden form.  The form is first placed on wooden wedges.  Then a wedge of mud is placed on top of the wall beneath the location of the first block.  Veneer blocks are used for the arch.  The inner edges of each block touch the inner edges of the blocks above and below it.  A mud wedge is laid on top of each succeeding block.  A straight edge is laid across each block as it is placed in the mud.  It MUST point directly at the bottom center of the arch in order to assure a symmetrical arch.
 

 


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After the blocks are all in place comes the moment of truth.  The wooden wedges are removed and the wooden form is carefully slid out the back of the arch.
 

Mud mortar is packed into any gaps between the blocks. 
 

The remaining courses of the wall are then built up around the arch.  Each block contacting the arch must be trimmed with a hatchet or saw in order to maintain the joint gap around the arch.
 

 
The stair-stepped buttress wall can be seen coming out of the shadow on the rear of the main wall.

After a "Mad Dog" flurry of activity the students finally ran out of mortar and block for their practice wall.  The novice Adoberos are now ready to strike out on their own and begin to apply the concepts learned at the SouthWest Solar Adobe School.
Southwest Solar Adobe School holds its Tucson, Arizona classes at the Old Pueblo Adobe yard.  The office building serves as a display of the talents and treasures available from  Robert and Rhonda Barnes.  Many features have been  incorporated in the facility by the Owner-Builder-Architect. 

 
At the rear of the office facility is a  beautiful garden complete with an outdoor fireplace and shady ramada.

 

The garden is surrounded by this plastered adobe wall. 
     


    A sub-floor evaporative cooling system prevents the air from being pre-heated on the roof top or in the attic.  This sub-floor ducting carries the cool air from the ground-mounted unit to the in-wall distribution boxes. 

If you want further information about building with adobe check out these links.  Adobe Builder magazine is a great resource for general information.  If you want specific answers to engineering or structural issues check with someone like seismic engineer Fred Webster, Phd. at "deatech" listed below.
Companies like Earthuprising manufacture a variety of earth-building materials.  Take a look, you might find just what you need.

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