Sunday, August 29, 2010

Semi-Stabilized Adobe Techniques

Our friends Bill and Barbara have been building ( in their spare time )
 a music and art studio next to their house in El Rito, New Mexico
which is in the northern part of the state.

We happened to stop by the other day to check on the progress.

This studio is a post and beam structure with semi-stabilized adobe fill 
between the posts. This is a bit out of the norm for adobe 
but a big advantage is that the building can be completely roofed in
 before you start the adobes.

Working in one's spare time this lessens the worry about weather
 while "slowly" building and gives a covered area
 to keep tools and materials dry.

They have things almost closed in and getting ready to wire and stucco
 over the XPS insulation, also called blue board. 
 Judging by some of the small pieces of XPS,
 Bill is doing a good job of reducing waste and saving material.
The different colored lines on the XPS are to mark electrical wire
 behind the XPS to keep from nailing through the wire.

This shows one of the posts of the post and beam structure.
These semi-stabilized adobe have a small amount of asphalt emulsion 
to protect them from water damage.
 When buying adobes from one of the suppliers of bricks 
( as compared to making your own ) they have become the norm.
 They are commonly laid up with a conventional cement mortar. 
Of course the traditionalists have a hard time accepting the semi-stabilized 
over the old way of just using adobe mud and straw in their bricks and mortar.

Remember the lines painted on the outside in the second photo?
The electrical lines are run straight through the wall
 to the outside and then run along the wall.
 The 2" of foam board on the ouside brings the stucco out far enough to satisfy
 the code requirement for the electrical cable to be 2'' deep from the finished surface.

This gives a nice view of the " gringo blocks " , 
the wooden blocks set into the wall to attach the door frame to.


  1. Is that styrofoam insulation on the exterior?

  2. XPS or EXPS is extruded polystyrene foam also called blue board or grey board. It is a sturdier version of expanded polystyrene ( EPS ) which is commonly referred to as styrofoam, the white foam board you may be thinking of. XPS is allowed to be used below grade as well as above and has a higher R-value. If you are not confused enough already you can also check Wikipedia, as well as many other web sites on line. I had to look this up when I was writing the post as I had forgotten much of this over the years. And there are even more rigid foam insulation boards such as poly-iso and various urathane foams. Each has specific characteristics and R-values. There is too much info. on this subject to be covered in one blog post but thanks for asking a very good question.