membrane under window well gravel

[Peter Louis]

tiny water stain noticed on the carpet under window well. The client blamed this memberane holding water & drain let stick out. Yes, normally we do not see the membrane in window well but I think it is better & won't hurt. The grade is ok. What do you think? What is the better solution except crack repair. A transparent cover? Thanks.

[John Kogel]

The membrane is not tight to the concrete below the window, and the drain pipe passes through it and pokes up above the gravel. The membrane is useless and the drain is useless. I think she's right.

[Peter Louis]

The membrane is not tight to the concrete below the window, and the drain pipe passes through it and pokes up above the gravel. The membrane is useless and the drain is useless. I think she's right.


Thank you John, I do not think this membrane is foundation damp proofing/drainage. This looks like just for window well. Is this better than just gravel? Before the perforated big-O filled with gravel was used as drain. No memberane needed. Now PVC pipe, Is membrane necessary?

[Mike Kleisch]

If the drain piping is perforated then I don’t think the drain is useless as water will still enter the pipe.

Not too sure about that membrane, but could see water getting behind it, especially if rain hits that side of the home. I envision rain hitting the home and running down the siding into the J-channel below the window and then drain out of the J-channel at the corners behind the membrane. You could try installing a piece of flashing behind the siding to kick the water out in front of the membrane. Always start with the obvious and work from there to find the problem.

A cover will help, but will also block ventilation when they open the window for fresh air.

[John Kogel]

Get rid of the gravel and the groundcloth, dig down and cut a couple of inches off the drain pipe. Then lay down poly and a skim coat of concrete sloped to the drain and sloped away from the basement wall.

[Raymond Wand]

In my opinion I would try an acrylic window well cover. What I see in the photo is typical installation for window well drain here in Ontario. The drain should go down to the weepers.

Alternatively the owner could put a garden hose in the well and let the water run and see if there is actually a leak due to cracked foundation. If it is a crack the least invasive repair would be polyurethane injection.