How to Install a French Drain
Installing a French drain is an effective method to divert water from getting into your crawlspace or basement. It involves placing a French Drain along your foundation footer.
Tools and Materials
Before we begin, let's gather all the necessary tools and materials.
Tools:
- Trench shovel
Materials:
- Non-woven Landscape fabric
- 4" Perforated Drain Pipe
- Round River rock
Step 1: Dig the Trench
Dig a 6" to 12" wide trench along the foundation wall. If you do it in sections, this will reduce the chance of undermining the foundation wall. It is recommended to dig 12" - 24" deep so that you are at or near the bottom of the foundation footer. These variances in the trench width and depth are due to the local area codes that require different depths depending on the soil and frost line.
Step 2: Compact the Soil
Compact any loose soil in the bottom of the trench. Either use a hand compactor or a 6-foot 4x4.
Step 3: Insert Landscape Fabric
Put unwoven landscape fabric in the trench to form a burrito. I used 6' wide fabric so it would extend up a few feet on each side.
Step 4: Add the First Layer of Rocks
Install a 2 or 3-inch layer of round rock on top of the fabric.
Step 5: Lay the Drain Pipe
Lay the 3" or 4” diameter perforated drain pipe on top of the round rock. The holes need to face DOWN.
Step 6: Add the Second Layer of Rocks
Put in another 2"-3" of round rock on top of the drain pipe.
Step 7: Wrap the Fabric
Wrap the fabric so it covers the rock.
Step 8: Add the Final Layer of Rocks
Add 2"-3" of round rock on top of the fabric. Alternatively, it can be covered with sod or other topsoil.