Friday, July 1, 2011

Earth Construction Techniques

As promised, I will share some of what I did in school with everyone.  I thought it would be fun to start off with a multi-weekend class I took last spring.  We had a visiting professor from South America who knew a lot about earth construction techniques, so he led a small class in building three different types of walls:  rammed earth, wattle-and-daub, and adobe.

I only got pictures on the last day of class, so I can only show you the finished products, but let me tell you, it was fun!  I think the most fun part (other than seeing the finished product) was mixing the dirt, sand, straw, and water with our feet.  It was really cold at first, but then your feet got numb, so it was fine.

We left a portion of each wall unfinished so later admirer's could see how they were constructed. 

Finishing up the adobe wall.
See how big the adobe blocks are!

The adobe was the neatest, I think.  We had to make the bricks and let them cure for a few weeks before we could assemble them into a wall.  The wall is two adobe bricks thick and then is covered with a layer of mud.  If this were actually an adobe building, it would need to be re-coated with mud every year to keep it from disintigrating.  With how thick it is, and the insulating properties of dirt, adobe structures are very good at staying cool in hot weather and warm in cool weather.  No wonder it was so common in the Southwestern desert!

Putting the last coat of lime plaster over the wattle and daub wall.
This wall was both the rammed earth wall (the lower portion, without the lime plaster), and the wattle and daub wall (the upper part, with they grey lime plaster).  Wattle and daub is the technique that the early pilgrims primarliy used when they arrived in the U.S.  It basically is a web of sticks woven togther and then plastered with several coats of mud.  By using lime on the last coat, we hoped to prolong the life of our wattle and daub wall because like adobe, without regular re-plasterings of mud, it will eventually disintigrate.  Infact, that is exactly the problem the pilgrims were having with the harsh New England weather.  The driving winds and rains would literally tear the walls apart, prompting the pilgrims to cover their walls with wood clapboards, thus creating the type of house you think of when you think about early America.

The finished rammed earth and wattle and daub wall,
with the layers revealed.

Rammed earth is another technique that has been used a lot over the ages and is the one that is really making a comeback in popular architecture today because it is easily mixed with concrete to make a structure that is up to code.  Rick Joy is probably the most well-known architect that employs rammed earth.

No comments:

Post a Comment