On its face, the location of a foundation perimeter drain seems like the simplest of details. The perforated drain line is run around the foundation next to the bottom of the footing.
At least that’s what many construction drawings show. But in some parts of the country, the drain is placed on top of the footing rather than next to it, and this discrepancy is at the root of Steven Knapp’s dilemma.
In a question posted at Green Building Advisor’s Q&A forum, Knapp writes this approach is not typical in his area, and that his waterproofing contractor is refusing to go along with it.
“Several years ago he switched to placing the drain (a rectangular pipe) on top of the footer and thinks this is the better method,” Knapp writes. “I’m annoyed and confused 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.”
Knapp’s builder is leaning in favor of the “on footer” method, but he’s willing to do whatever Knapp thinks best.
“So what is industry best practice?” he asks. “Putting the pipe next to the footer makes intuitive sense to me, but I know that what’s intuitive isn’t always correct. I just don’t want a basement that leaks.”
That’s the topic for this Q&A Spotlight.
The drawings are just plain wrong
Yes, writes James Morgan, we’ve all seen foundation drains drawn that way many times but the drawings are wrong.
“I know that’s the standard drawn detail and I’ve seen it a thousand times, but I think it’s a bad one, and there are several important [performance] reasons that no one ever builds it that way,…