How to Build a French Drain
- striping spray paint
- top soil
- 6' drain pipe (or more, if needed)
- roll of landscape fabric
- landscaping stones
Determine Area for Re-Routing and Draining
Locate the appropriate area of yard for excess water to be re-routed. Choose a location where the flow of water won't affect neighboring properties. Determine a slightly downward-sloping route at least 1 meter from walls or fencing that's clear of any obstructions such as posts, trees or shrubs. Tip: Drains that slope 6" for every 50 feet ensure the best result. Use striping spray paint to mark drainage route.
Create a Trench and Add Gravel
Referring to spray paint marks, use shovel to dig a 6" wide trench with a depth no greater than that of the nearest foundation (Image 1). Tip: Proper trenches run parallel to buildings and horizontally across slopes. Once trench is dug, add a 3" layer of gravel along bottom (Image 2).
Add Fabric Lining
Use landscape fabric to line entire span of trench atop layer of gravel, leaving roughly 10" of excess fabric on each side of trench.
Insert Drain Pipe
Place drain pipe atop fabric lining, then add gravel, covering pipe completely. Leave approximately 5" between top of gravel and ground surface.
Fold Over Excess Fabric Lining
Fold excess fabric over gravel, creating an overlap. This will help protect the lined drain pipe.
Fill and Cover Trench
Use shovel to fill trench with sand then topsoil. Cover sand and topsoil with turf and add a bed of stones around open end of drain pipe.