Build Your Home with Adobe: Use the Material Under Your Feet
Greenhomebuilder.com states the best adobe soil will have 15-30% clay, to bind the material. The rest will be mostly sand with some aggregate. If the mixture is off, the bricks may shrink and crack or fragment too easily. The proper mixture is critical to your success. Today’s Adobe may have some cement mixed in to stabilize the product and create a brick that will stand up over time. Adobe can be used for more then walls, when used for floors a thin slip, (watered down clay mixture) is poured over the floor. The finished floor is polished with oil to give a nice shine.
When an adobe structure is built it is imperative that the ground under the walls is tamped, or compressed. Adobe is very heavy as the walls are usually between 12″ and 24″ thick. It’s all this mass that creates a thermal wall. The heat of the day doesn’t penetrate inside the house, but in the evening the heat that has been collected by the wall will maintain a comfortable temperature inside the home. Adobe homes are very energy efficient requiring only a small fireplace to supplement the massive heat collector the adobe house has become.
Wall construction is like building a running bond brick wall. The final coating will be adobe plaster. Walls that have been stuccoed with cement will fail as moisture will get under the stucco and it will crack and pull away. Roof construction will begin with the placement of flattened beams on top of the walls to spread the load of the roof evenly along the wall. The installation of long timbers or logs will span the distance from side to side of the house. Spaced about 24″ apart, they will carry the load of the roof. Covering these heavy logs will be smaller branches laid close to each other forming the interior ceiling of the roof. a layer of clay/straw mixture is then placed on top of the smaller branches topped with a layer of adobe bricks. A final layer of clay/straw mixture will finish the roof.
The walls will continue up above the roof level and a slightly sloped surface should finish the roof with openings to allow rain water to run off. Todays adobe home may have the roof coated with a white reflective rubberized coating to add to the longevity of the surface and to also aid in keeping the interior cool during the hot south west days.
What more cost effective structure could you build, using the dirt under your feet and a few bales of hay. Add a bit of water, mix well and form into a brick and start building. Labor intensive yes, but also inexpensive for the do-it-yourself builder.
For a much more detailed look at building your adobe home www.greenhomebuilding.com/adobe.htm will provide you with extensive information and answer many questions for you.