Well I am trying to plan a french drain project to alleviate water coming into my basement. I’ve got a lot of engineering questions, if anyone can guide me in the right direction I would appreciate it! First some background. As you can see from the picture, my roof has a main section that then runs down in the front to a patio roof angle in the opposite direction. The problem is my attic is finished with vaulted ceilings, so that this melts the snow, runs down to the patio roof, and forms ice dams in the gutters. This is an issue I’ll address at another time hopefully, if there is even anything I can do about it.
The symptom is that I am getting water in my basement in the coal room that is below the patio. To help solve this, I plan to install french drains all around my house. The front of the house is labeled, and there is a steep grade that goes towards the rear of the house. On each side of the house are cement steps, which are attached to my neighbors houses. My plan is to dig a trench between the steps and my house, lay down fabric liner, put down 2-3 inches of washed gravel, lay the french drain on top of this, fill the trench with washed gravel, then lay 3" of red lava rock covering the whole surface area between the cement steps and my house. I think (hope) this will work pretty well and look nice as well, but I have a few questions:
- How far in " do I want the drain from the house on each side?
- How deep do I want the pipe to be sitting in the ground? Remember my goal is to prevent water from seeping into the walls in my foundation.
- What is the best way to route my drainage pipes from the downspout to the rear of the house down the grade? Right now there is flex tubing running just underground down the house to the rear from the downspout, can I connect this to the french drain (I’m thinking no?) if not how should I route it so it doesnt interfere.
- Do I want the holes up or down, assuming they are on one side?
- Do I want to use solid piping or flex piping?
Right now grass is in the front and dirt on the sides, so I am hoping this solves my water problem, and also gives me an opportunity to landscape around the perimeter of my house. Which brings me to my last question, will it be safe to plant anything in the front of the house, like a shrub, or will roots interfere eventually with the drain?
Thanks for any insight you can provide!