How to build a French drain

drainagefrench-drainrain

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?

Best Answer

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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