What is involved in a successful french drain?
Whether you hire it done or try it yourself, here is the process: • Cut a channel at least 9″ wide. You can make the depth as little as 9″ if needed to avoid sensitive tree roots, but a foot or more is better. • Slope: Sometimes a french drain is installed in low areas and can only be put in flat. If it ends somewhere that water can go, even this will collect excess water and allow it to flow off site. Ideally a minimum slope such as 1/8″ per foot should be used if possible. • Always use drain cloth. A trench filled with rock will fill in with dirt and be almost useless in two years. As indicated in the picture use the 3′ wide cloth to line bottom of trench. Some simply fill the trench with the drain rock to within 3″ of the top, fold the fabric over and cover with soil. • Three or four inch perforated drain pipe aids in overall performance. Holes go down. Some slid a pipe sock over pipe for extra insurance. It is made of the same soil filter fabric. • Drain rock can be any of a number
