Grading and Drainage Problems | House Foundation and On a Hill

by Nina Riegler
(Bloomington, IL)

Here's a question regarding grading and drainage problems at the house foundation.

Finding your site may be a "godsend" for us. We are replacing sections of our 30 yr old foundation that is bowing in from weight of dirt on the basement walls. How can we landscape to drain water away from the house? Retainer block is an option as we used it on the other side of the walk out.

ANSWER

Hi Nina,
Without having additional information (lay of the land, surroundings, grading pitch information...even photos), it's difficult to give exact advice on grading and drainage at your foundation. However, here are the simple rules to get water away from a house foundation for proper water drainage.

Pitch the land away from the foundation at 1/4" per foot for a minimum of 5 feet. If this can slope gently away to an area pretty far from your house, this may be all you need.

Otherwise, you can create a swale. This is a "lawn channel", similar to a modest stream that gets lower and lower as it get further away. This must empty either into a wooded area, a rain garden, a pipe that leads elsewhere, etc. (See pages below.)

If you can't pitch the water away from the house due to certain constrictions, you can install a french drain. This is installed along the foundation. It has holes in it where the water can enter. The pipe is then gradually pitched to an area where the water can exit. There are various options for the exit area.(See below.)

Please visit the following pages where you will find more detailed information for grading and drainage.

Landscape Grading - general information on all types of drainage solutions. It's an expansion of what I've written above.

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