I'm putting in a French drain around my house this summer and need some advice. I'm using a non-woven geotextile to wrap around the perforated pipe and drain rock. My question is whether or not I should place gravel underneath the fabric at the bottom of the trench. I've heard two sides to this: one says that gravel will help prevent soil from clogging the fabric from below, while the other claims it might block water from getting into the perforations in the pipe. What do you recommend? Thanks!
1 Answer
It's really situational! You should think about factors like how cold it gets in your area, how deep the piping will be in relation to your foundation, and what type of soil you have. Also, make sure you pick a geotextile specifically designed for French drains—stay away from the thin stuff they sell at big box stores!
I'm in the Pacific Northwest with clay soil, and the frost line here is just a few inches down. My pipes will be 1-2 feet deep below the foundation.