|
Exterior Surface Grading:
 | The grade or slope of the soil should be designed to direct surface
water away from or around the home. Water accumulation next to the home
can lead to water penetration problems such as structural damage to wood
framing, interior damage to finished surfaces and damage to the
homeowners' belongings. Additional problems such as hydrostatic pressure
against foundation walls or surface water mixing with expansive soils next
to or under a foundation can lead to cracking of the slab and foundation
walls. Proper grading in conjunction with a gutter and downspout system is
one of the easiest ways to manage surface water, reduce the possibility of
water penetration and structural damage from hydrostatic pressure, and
control the water content in expansive soils.
|
Grading of the Soil Around the Perimeter of the Home:
| The soil around the perimeter of the home should slope away (at a
minimum of six inches for the first 10 feet) from the foundation to
prevent rain water from accumulating next to the foundation walls. Soil in
this case does not refer to the top-soil but the layer of soil that is
impervious to water such as clay, which directs the water away from the
house. Many times the top-soil is porous (as would be used for planting)
and absorbs the surface water. The sub-layer of clay or similar non-porous
soil prevents the water from continuing in a downward movement and directs
the water laterally. If non-porous soil next to the foundation slopes
toward the house, water will begin to accumulate.
|
Grading of the Lot:
| The overall lot grading is also an important concern since surface
water may enter from adjacent properties. Generally, if the house is
located on a slope or on a lot that receives water run-off, swales are
often used to direct the water around the house.
|
Swales:
| Swales are shallow ditches or depressions in the landscape that
capture the water run-off. Then, like a small creek, the water is directed
around and away from the house. |
|
