Tree Roots and Root Barricades
There are many causes for concrete slab and home foundation failure including drainage problems, moisture fluctuations due to weather conditions, soil conditions and sewer line failure. However, in our experience, the biggest single cause is differential settlement due to large trees. Large trees like Oak, Arizona Ash and Chinese Tallow have extensive tap root systems that extract large amounts of water from the soil, which can cause major damage and require home foundation repair. These large trees remove disproportionate amounts of moisture from soils under and adjacent to foundations. That is, a large tree on one side of your house will cause your home foundation to settle faster in the area the tree is located. That side will tend to settle while the other sides of the house do not causing a home foundation to crack.
If a tree is very close to your home then the solution is to remove the tree to avoid a home foundation repair job. If the tree is further away from the home foundation (20 to 30 feet), we can install a root barricade three to five feet from the exterior walls of your home. The root barricade will prevent tree roots from removing moisture from the soil that is in the immediate vicinity of the home's foundation.
Installation of root barricades requires overlapping sheets of non-biodegradable 1/4" thick Plexiglas to a depth of approximately 30" inches. This will prevent tree roots from growing past the root barricade.
In our opinion, root barricades can be helpful in preventing interior settlement problems, but will be limited in preventing exterior settlement. That is, they can help prevent the need for interior piers but not exterior piers if the tree is close to the house.