I recently finished (well, almost) a curtain drain around my house to help deal with poor drainage problems. It’s a two foot deep trench, filled with gravel and drained to daylight, that wraps around the whole house and is centered under the eaves.
The curtain drain follows the shape of the house, and I dug it to be under the eaves of the house. In case we never get gutters on the house, anything that sheds off the roof will fall directly in the trench, where water will be whisked away to daylight, to the northwest of the house.
It’s two feet deep, which is six inches deeper than the trench under the foundation. Theoretically, very little water should even get to the trench under the foundation, because it should be intercepted by the curtain drain first. I put two inches of gravel at the bottom, then a 4″ perforated drain tile, and then filled up the rest of the trench with tamped gravel, leaving a couple inches at the top. In the very near future, I will get some landscaping fabric to lay over the gravel, and then shovel a couple inches of topsoil over the whole trench, hiding it from view.
The trickiest part was mating the curtain drain to the existing daylight drain. I dug up the original daylight drain, removed the gravel, and peeled back the pipe. Next I re-dug the daylight drain to the depth of the curtain drain, installed the 4″ perf pipe to end at the exit drain, put screen on the two ends of the pipe, and then threw gravel in and laid the original exit drain back in the trench.
So far, so good. I can see water exiting the drain.
Previously, the area around the house would get intensely saturated with water during heavy storms. We haven’t had any major storms this year yet, but I imagine this extra drainage will make a big difference.