soil around house foundation

by Brenda Wright
(Round Rock, Tx)

We had our foundation leveled about 4 years ago raising our house up about 4-1/2 inches. The area I live in has been in drought ever since. The soil all around our house has settled further despite watering causing a great deal of stress on our plumbing. We've brought in soil to fill gaps between the yard and the foundation. How high up the foundation should we be adding soil? What we've added thus far has been swallowed up exposing the concrete below the forms and sometimes big gaping holes. What should we plant to keep the soil from moving away. We layed sod but it did not survive.

ANSWER

Hi Brenda,
Regarding how high soil should be along your house foundation, it depends on how high your foundation is. Eight inches of the foundation should be exposed from the ground up. So if your foundation is 12 inches high, you can have 4 inches of soil along the bottom.

Your soil might be settling because it is not on the correct base and the soil is sandy. I am not familiar with this as it applies to house structure. I know that clay soil will keep water from percolating down much better than sandy soil. Also, your ground must be sloped away from your house at a minimum of 2% or 1/4" per foot. A combination of clay soil and correct grading should help the situation from a landscape perspective.

See this page: Landscape Grading

If it is not graded correctly, water might be seeping down at the perimeter of your house, compromising the soil there. If this is the case, then another alternative is to install a french drain to take the water away. This is a perforated pipe set along the perimeter of your house with a layer of stone on top of it. The pipe has holes in it where the water can enter. Then the pipe is sloped to lead the water away to a determined area.

You should take this all into consideration, but since you had problems with your house settling, I would contact a structural engineer for a consultation.