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There's a shed near the side of the house with a roof that's pitched to shoot water at the house's foundation. That side of the house also has no gutters. There's a very slight grade to send water towards the front of the house. House is brick veneer, on-slab.

How can I build a drainage system to carry water away from the foundation?

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up vote 11 down vote accepted

Here is a pretty quick explanation.

  1. Starting from where the water will enter the drain and ending where the water will flow out, dig a ditch that's about 10 inches deep and 6 inches wide. Keep in mind that you will need to dig deeper if your starting point slopes upward.

  2. Lay about 2 inches of rock into the trench before placing the pipe lengthwise into the ditch.

  3. Cover the pipe with another layer of rocks, again about 2 inches.

  4. Fill in the remaining space with soil and then plant some grass.

Here is a pretty good video, which also shows it's a good idea to add a clean-out.

They also say you should not use flexible corrugated perforated plastic drain pipe, because it cannot be cleaned like rigid pvc can be.

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Here's another article about a French / Trench drain:

Basically the same idea, except he doesn't recommend lining the ditch with fabric or putting a sock on the pipe. He does recommend using rigid perforated pipe instead of the corrugated pipe with slits in it.

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I like the idea of omitting the fabric (expensive!). Great link. – Steve Jackson Nov 19 '10 at 5:25
@Steve - I dug a French drain on the uphill side of our house 30 years ago. I don't think we even had fabric back then. It worked great - for the first 10 years. I've had to use a sump pump ever since. That crushed rock isn't good for much once it's all silted up. – Ed Staub Sep 24 '11 at 13:38

Depending on the area , and your costs, you could also just buy a prefabricated french drain and save yourself some times. Your BIG local hardware store would have something like this:

enter image description here

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