The house I previously lived in was a split level. Half of the downstairs was a two car garage and the other half was an unfinished basement. We had plans to turn it into a master suite, but first we had to stop the basement from leaking.
Every time there was a heavy rain, water would start seeping out of the base of the foundation wall on the East side of the house. This side of the basement was completely underground and the foundation wall went all the way to the ceiling. The ground outside was part of the backyard and it didn’t seem to slope dramatically toward the house.
It was really hard to tell exact why the water was coming in, but I knew that installing a French drain would be the best solution.
The first step was to determine exactly where the water was penetrating the concrete. I was fortunate to be home one day when it started pouring rain after it had been dry for a while. I started going down into the basement every 30 minutes and I finally saw the moisture start to build up in one specific area. I kept checking it regularly to see if water started seeping in from anywhere else.
The good news is, even though the water ran all over the floor of the basement, it was only coming in at one spot. So I knew that I needed a French drain on just the East wall.
We started by jackhammering a strip of concrete about 8″ wide all along the West wall. We didn’t open up the concrete right against the wall because the footing is there and we wouldn’t be able to access the earth below. So we used the jackhammer to open the concrete about 4″ off the wall.
Once we cleared out the rubble, we dug out the trench so it would slope toward where we planned to put the sump pump. The wall that would eventually be framed over this area would be the back wall of the master bathroom which sits next to the garage. So we jackhammered up a hole in the concrete in the garage and put a sump basin in there.
After you lay a few inches of gravel in the trench, you have to put in a perforated pipe that will catch the water and lead it down to the sump basin. There is a lot of arguments about whether you put the holes up or down when you install the perforated pipe and I’ll tell you the answer. The holes go down. The reason our basement leaked was because the water table would rise after a heavy rain. So the water comes up, hits the holes and runs down the pipe. Water takes the path of least resistance.
You want to wrap the pipe in some silt fabric so it doesn’t get clogged with dirt. You also want to put a 90 degree bent at the opposite end of the pipe from the sump pump so it sticks up out of the floor a little bit. This gives you access to clean out the pipe every so often. Then you want to put another layer of gravel over the pipe before you pour concrete over it.
We had the pipe run into the sump basin and put a shiny new sump pump in it. You can plug the sump pump into any outlet in the garage, but the best thing is to have a dedicated 20 amp circuit just for the sump pump. The only way to get the water out from there was to run a 1 1/4″ solid PVC pipe around the outer wall of the garage and out the front of the house. Instead of letting water just shoot out the front of the house every so often (probably severely confusing the neighbors), I ran the PVC down into the downspout drain that was right below.
We’ve had a handful of heavy rains since then and the basement has stayed bone dry. This means we can safely frame over the area and turn it into a master bathroom to make that half of the basement a master suite.