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Adding french drain with sump to 100 year old basement

Adding french drain with sump to 100 year old basement


Old 12-18-12, 05:52 PM
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Adding french drain with sump to 100 year old basement

K trying to describe the layout of my lot is hard...western pa, middle of hill so alot of water flows past my house. half the house is fine (the side with a floor drain doesn't get wet) the other side is always getting wet, use to be really bad I graded and filled in a window well hasn't been as bad but still get water coming in at the bottom of the foundation even with all the grading.

Ideally I know best scenario would be dig out entire foundation and put in membrane and french drain at footer....but I have a 100 year old field stone foundation and suspect footer is either compacted gravel or its just sitting on dirt so rather not disturb that earth if I can avoid it, on back of the house wouldn't be surprised if I'd be distrubing virgin soil to put in an exterior french drain....

So my idea was to put in a interior french drain on the wet side of the house and then have a sump pump to pump it out the window to a drainage pipe I have coming off the gutters....

Question is what kind of sump pump to get anyone ever attempt this before. I'm fairly comfortable with plumbing (had to redo all my plumbing before I moved in) but not sure on size of sump or what size pipe to use...guessing pipe size is dependant on the sump I get.

Going to be installing a large dehumidifier down there but think having the dehumidifier and a sump would be the best way to rid my basement of high humidity and water....

So I assume I would remove concrete floor around foundation then dig a trench and grade it to where the sump goes so water flows to the sump, put down some kind of moisture barrier, gravel, purferated pipe, then more gravel then a vent along the foundation for water to seep in then cover it back over with concrete? Then have a clean out where the sump goes with pvc taking it out the house?

Thanks for any help...feel free to ask for more details
Old 12-18-12, 06:17 PM
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You were right the first time. Exposing the foundation & sealing it with a membrane is the best way to go. You could do half at a time, if you are worried about disturbing the structure.
Old 12-18-12, 06:59 PM
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While clearing away from the foundation and installing a membrane might be ideal, you're right. Doing that to a field stone foundation might create a whole new set of problems.

Ii prefer passive solutions over active ones. It seems to me that trenching in a drain close to the foundation - say 2' or so out - would capture 99% of the water.
Old 12-19-12, 01:13 AM
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Intercepting the groundwater on the exterior of the house is always a better plan than trying to deal with it once it gets into the walls. As suggested, stay a foot or two away from the walls, and install your drain lines and exterior sump pit accordingly. Had one at a previous house in Colorado, and it worked like a charm. Never had water in the basement, but the exterior pump kicked on frequently during and after heavy rains. For additional protection, install a layer of bentonite (or very heavy plastic) under the topsoil, between the house and the new drain line runs.

An additional advantage of doing it as suggested will be that no concrete floor removal/replacement is necessary in the basement.

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