How Should a Foundation Drain be Installed
Steven Knapp has run into trouble with the contractor who’s waterproofing his foundation. Knapp wants the perimeter foundation drain installed next to the footing while the contractor is a convert who now installs drains on top of the footing. The contractor refuses to budge: Either the drain goes on top, or find someone else to do the work.
As Knapp explains in a post at GreenBuildingAdvisor’s Q&A Forum, all he wants is a dry basement. “I’m annoyed and confused,” he writes, “since I was advised by another credible expert that placing the pipe on top of the footer would greatly increase my chances of springing a leak.”
There’s no shortage of opinion on this seemingly simple question.
One camp argues that the key to a dry basement is keeping the center of the perimeter drain below the level of the slab. Violate this rule of thumb and you’re courting problems.
The other side would have the drain pipe right next to the vulnerable seam between footing and foundation. Why put the drain a foot away from this critical area?
Those two points of view are at the heart of this Q&A Spotlight where posts also touch on whether the drain pipe should be pitched or level, and whether backfill should be compacted.
Most detail drawings show that a footing drain should be located next to the footing. But some builders prefer placing the drain pipe on top of the footing. Which way is correct?