How Thick Should Adobe Walls Be?
Depending on the climate and region, adobe walls may be anywhere from 10 inches thick to 14 inches thick or even more. However, the thickness of an adobe wall should be determined by the construction materials used and the desired strength and stability.
Bricks: Adobe bricks are made from half sand, one-third clay and one-sixth straw or other organic material. They are then mixed with water to create a liquid, malleable consistency and are cast into uniformly sized blocks before they are assembled. They are then stacked on top of one another and left to dry naturally before being plastered over or exposed.
Mud Plaster: A mix of sand, mud and lime, this type of plaster is usually used on historic adobe structures because it can be smoothed by hand and exhibits similar expansion under heat to the bricks. It is very durable, but it cracks easily when exposed to moisture.
Lime Plaster: This type of plaster, which is also made with sand and lime, is stronger than mud plaster but it can be difficult to smooth out manually. It can crack if exposed to moisture, and it can be very time-consuming to apply.
Repairs: When adobe structures need to be repaired, it is important to use the same building materials as were originally used. This ensures that the repairs will not cause problems that could exceed the original ones.
Foundations: The ground below the adobe structure should be compressed as much as possible to prevent cracking, especially in areas of high frost-heat and high groundwater table levels. Modern construction codes require that the footing and stem wall of an adobe structure be 24 inches or more thick, as well as have reinforcement in the wall to resist uplift forces.
Roofs: The roof should be supported and anchored to the adobe walls with bond beams. The bond beams should have continuous rows of reinforcing between the required members to resist uplift forces. They should also be provided with washers, which are oversize and embedded in the adobe.
Stucco: Some people worry that cement based stucco is not compatible with adobe walls, but you can use standard cement/lime stucco over an adobe home without any problem. In fact, some people have done this successfully in their homes.
Sealing: If your adobe walls are properly sealed, they should be relatively impermeable to water. To test for this, simply toss some water against the adobe wall and see if it beads up or bounces off. If the water doesn’t bead up, it is probably leaking out. If it does, then the adobe walls are protected and you can start making your repairs.
Intrusive vegetation: Plants that take root in adobe walls and foundations can degrade the structural integrity of an adobe structure, so they should be removed as soon as possible. They can also create a breeding ground for insects, rodents and birds that will attack the adobe, making it more susceptible to damage from pests and erosion.
