Foundation Maintenance & Drainage 3
It is recommended that a least six-inches of clearing be developed between the grade and the wall siding. This will minimize surface water entry between the foundation and the wall material in turn minimizing wood decay.
Poor drainage at residential projects in North and West Houston can result in saturation of the surficial sands and development of a perched water table. The sands, once saturated, can lose their load carrying capacity. This can result in foundation settlements and bearing capacity failures. Foundation in these areas should be designed assuming saturated subsoil conditions.
In general, roof drainage systems, such as gutters or rain dispenser devices are recommended all around the roof line with gutters and downspouts kept unobstructed by leaves and tree limbs. In areas where expansive soils are present, the gutters should be connected to flexible pipe extensions so that the roof water is drained at least 10-feet away from the foundations. Preferably the pipes should direct the water when sandy soils are present, at least five-feet away from the foundations.
If a roof drainage system is not installed, rainwater will drip over the eaves and fall next to the foundations resulting in subgrade soil erosion, and creating depression in the soil mass, which may allow the water to seep directly under the foundation and floor slabs.
The homeowner must pay special attention to leaky pools and plumbing. In the event that the water bill goes up suddenly, without any apparent reason, the owner should check for a plumbing leak.
The introduction of water to expansive soils can cause significant subsoil movements. The introduction of water to sandy soils can result in reduction in soil bearing capacity and subsequent settlement. The homeowner should also be aware of water coming from the air conditioning drain lines. The amount of water from the condensating air conditioning drain lines can be significant and can result in localized foundation distress.
As the air conditioner runs, it pulls a significant amount of water out of the air and the water normally is sent into the home’s plumbing system drain lines. If those drain lines are not properly working and the water is sent to the outside of the home via the secondary drain lines, (commonly placed over a window in the soffit) where this extra water is introduced to the surrounding soil, this could adversely affect the foundation.
Similarly, if either a fresh water plumbing line or a waste water drain line has a leak in them under the house or in close proximity to the foundation, structural issues could become significant.
