Help on drainage issues


Old 04-20-16, 03:06 PM
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Help on drainage issues

What are your thoughts on moisture control under the house? We have a house near Seattle, and are having some moisture in our crawl space, partially because of a parking lot behind our house, and partially because of the ton of rain here in Seattle. I have spoken with different professionals and one suggested digging trenches and piping the gutters out to the storm drain. Another suggested perforated pipe all around the crawlspace, pumping through a sump pump and into a into a dry well. What are your thoughts on the two solutions? Do you think drywells are a bad idea?
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Old 04-20-16, 06:08 PM
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There has to be thousands of post on this one subject on this one subject on this and any DIY site.
All say the right way is to address the issue on the outside, not the inside.
Google "french drain"
If your down spouts are just dumping water next to the foundation there useless.
Grade needs to sloop away from the house.
No mulch or flower beds forming holding ponds next to the foundation.
Old 05-11-16, 07:53 AM
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Foundation / Downspout drain tile

I am currently installing foundation drain tile using 4" perforated PVC pipe on a 1000 sf cottage on a crawlspace. I have installed a membrane as well as used a rubber sealer (paint on) on the block wall. I am, at the same time, using the same trench to run solid PVC pipe to connect 4 ( out of 8 total on entire house ) downspouts. For the downspouts I am wondering whether 4" pipe is adequate or if I should use 6" pipe which is logically much more difficult to work with.
Any experience with this dilemma ?
Old 05-11-16, 08:03 AM
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Claire: Joe is correct & I'll add that the foundation must be sealed first, from the outside. I would only use a sump pump if the water table is high.


I have installed a membrane as well as used a rubber sealer (paint on) on the block wall.
I hope that was done on the outside of the foundation.

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