Footing Drain Requirements

The Footing’s Role

• The footing is the concrete pad that runs beneath the foundation walls. The foundation contractor will pour the footing before forming and pouring the walls. A standard footing is about three times as wide as the foundation wall is thick. For example, if the foundation walls will be 8 inches thick, the footing should be 24 inches wide. When the wall is in place, this will leave a footing ledge of 8 inches on both the outside and the inside of the foundation wall. Local building code may require you to install a drainage system on top of the footer, or beside it.

Drain Tile

• Drain tile is a flexible, perforated pipe, covered with a mesh sock. For exterior installation, the pipe may sit on the footer or beside it. For interior installation, the drain tile must sit in a trench at least 8 inches below the top of the inside footer ledge. Interior drainage systems are deeper to accommodate the future concrete floor above them. On both exterior and interior installation, you will surround the drain tile with 6 to 18 inches of rock that acts as a filter to keep sediment from entering the drain tile and clogging the pipe.

Water Collection

• Once water enters the drainage system, it has to go somewhere. A sump bucket, installed beneath the basement floor for an interior drainage system, or in a covered hole outside the foundation for an exterior drainage system, collects the water. Because drain tile is a continuous pipe, the water collected in the pipe will drain into the sump bucket when both open ends of the pipe extend into the bucket. A sump pump sits in the sump bucket, and when the water in the bucket reaches a predetermined level, the sump pump turns on and pumps the water up and out of the bucket to the ground above.

Considerations

• Footing drains work well, but the best practice is to reduce the amount of water next to the foundation when possible. By grading your yard so that it slopes away from the foundation, and by installing guttering and downspouts, you will reduce the amount of water that reaches the drain tile and triggers the sump pump.