Messages and Online Forum Q&A

Re: french drain with holes facing up?

From: info@builderswebsource.com
Category: Foundations and Basements
Remote Name: 207.82.209.165
Date: 07 Apr 2001
Time: 04:54 PM

Comments

Generally, the holes for French drains should be pointing down, or at least oriented in a downward direction. This is counter-intuitive, as people think this will cause the water to drain out of the pipe, rather than into it. However, in order for a French drain to function properly, you want hydrostatic pressure to force the water through the bottom of the pipe, which effectively lowers the water level in the trench to be consistent with the bottom of the pipe (known as the invert), as opposed to the top of the pipe.

Builders Websource offers a printable Tech Note in PDF format on French drains and drainage called "Principles of Residential Drainage and Basement Waterproofing," available through Amazon.com by clicking here.

However, the orientation of the holes may not be the only problem. Water in your basement can also be caused from improper foundation waterproofing in the first place. It's also possible that the French drain is clogged or does not divert water away from the foundation. Do you know where the French drain goes? Is there a sump?

Reading the Tech Note on French drains should help you to better understand the principles of drainage.

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