Landscaping and Foundation Maintenance
General. A house with the proper foundation and drainage can still experience distress if the homeowner does not properly landscape and maintain his property. One of the most critical aspects of landscaping is the continual maintenance of properly designed slopes.
Installing flowerbeds or shrubs next to the foundation and keeping the area flooded will result in a net increase in soil expansion in the expansive soil areas. The expansion will occur at the foundation perimeter. It is recommended that initial landscaping be done on all sides, and that drainage ways from the foundation should be provided and maintained. Partial landscaping on one side of the house may result in swelling on the landscaping side of the house and resulting differential swell of foundation and structural distress in the from of brick cracking, window/door sticking, and slab cracking.
Landscaping in areas where sandy, nonexpansive soils are present with flowers and shrubs should not pose a major problem next to the foundations. This condition assumes that the foundations are designed for saturated soil conditions. Major foundation problems can occur if the planter areas are saturated, as the foundations are not designed for saturated (perched water table) conditions. Then problems can occur in the form of foundation settlement, brick cracking, etc.
Sprinkler Systems. Sprinkler systems can be used in the areas where expansive soils are present, provided the sprinkler system is place all around the house to provide a uniform moisture condition throughout the year.
The use of the sprinkler system in parts of Houston where sandy soils are present should not pose any problems, provided the foundations are designed for saturated subsoil conditions with positive drainage away from the structure.
The excavations for the sprinkler system lines, in the areas where expansive soils are present, should be backfilled with impermeable clays. Bank sands or topsoil should not be used as backfill. These soils should be properly compacted to minimize water flow into the excavation trench and seeping under the foundations, resulting in foundation and structural distress.
The sprinkler system must be checked for leakage at least once a month. Significant foundation movements can occur if the expansive soils under the foundations are exposed to a source of free water.
The homeowner should also be aware of damage that leaking plumbing or underground utilities can cause, if they are allowed to continue leaking and providing the expansive soils with the source of water.
Foundation Maintenance: Landscaping & Foundations 2
