Determine where to route the water by assessing the landscape and having a high point and lower point so the drain can be sloped to move water away from the area that requires drainage.
Dig a trench 18 inches to 2 feet deep and at least 18 inches wide from the highest point to the lowest point. The trench can be curved, but keep the curves soft because the water can become trapped behind sharp curves. Lay the 2x4 in the trench and place the level on the 2x4 to ensure that there is a constant downward grade. Move the 2x4 as you continue digging the trench.
Use a tamper to compact the soil at the bottom of the trench. This will help to ensure that the gravel or crushed stone does not settle into soft soil. Use the level to check for downward grade; add or remove soil as needed to create a smooth bottom to the trench.
Fill the trench with 4 to 6 inches of crushed stone or gravel, and tamp the stone to create a firm foundation to reduce settling after filling the trench completely with stone.
Fill the trench with crushed stone or gravel. Rake the stone into place so it is flush with the ground.
Things You Will Need
- 6-foot 2x4
- Gravel or crushed stone
- Heavy duty rake
- Maintain the function of the French drain by keeping the top free of debris. Use a leaf blower to blow leaves, grass clippings and other debris off the top of the French drain. Monitor for and remove roots from trees or surrounding plants to prevent the roots from clogging the French drain and reducing performance.