The Depth of Foundation Drainage Tile

Dig a canal using a shovel around the perimeter of the foundation. The canal must feature a straight-line extension to the nearest ditch or other outlet. The canal should be at least 8 inches wide. Once you reach the bottom of the foundation, dig down an additional 18 inches.

Begin at the highest point of the canal and dig a 1/8-inch decline for every foot of distance around the perimeter. This is to pitch the canal so water flows toward the outlet. Tamp down the dirt at the bottom with a manual tamper.

Pour 6 inches of gravel into the canal and shape it into a shallow "U" with the back of the shovel.

Lay 4-inch rigid perforated PVC drain tiles in the center of the canal. Use elbow connectors to attach lengths of pipe at the corners. Turn the holes to point downward if there are only holes on one side of the tiles.

Fill the canal with gravel until it is about 6 inches from the surface and shape it into the shallow U. Creating a slight dip in the gravel helps control the flow of water. Lay landscape fabric on top to block debris.

Add equal portions of sand and dirt into a wheelbarrow and stir with a shovel. Fill the canal with the mixture so the soil around the foundation is more absorbent.

Plant flood-resistant shrubs or grass around the foundation so the soil won't erode. As root systems row, the plants will help absorb excess water.