Sunday, October 24, 2010

Installing a downspout drain

My house is on a slope. As a result I get a fair amount of water against the foundation next to my workshop. Some of the water leaks into my workshop when it rains heavily or for extended periods of time. The drainage runs around the back of my house but that area is flooding now - and that will be a separate project. 

So I decided to fix that by installing a downspout drain to divert the some of the water where it won't cause the problem anymore - my driveway. This involved digging a trench, which took a few hours of hard labor. I have clay soil, with lots of rocks. The trench is about 30 feet long total.

Since this is only one downspout from a small roof section, I used 2" DWV (drain/waste/vent) PVC pipe. Normal drain pipe is 4", but that would be a little overkill here. Home Depot only had 4" downspout adapters, so I used a reducing fitting. I discovered thin-wall PVC drainage pipe isn't directly compatible with DWV pipe, but they sell 4" adapters, so I got one.

All of the fittings except for the downspout adapter are solvent welded. The most important thing is to establish a downward slope on all sections of the drain. I used a level and put some large rocks in the trench to prop up the pipe in spots to achieve an even slope.


I then back-filled the trench with the dirt. I sprinkled some grass seed on it to help prevent erosion in the future as well as keep it drier. I purposefully did not tamp it down to give the grass a chance to grow. The fill will settle with time.

Now to see if it works when it rains next. If no water gets into the workshop, its a success.


benthomasson said...

Man that was a log of digging.

Anonymous said...

Good job, I would have just run it on top of dirt.