Friday, January 23, 2009

All hail the trench!

The trench drain is yet another project I thought would be pretty easy that really wasn't. Sadly, the ground is so rocky that there were several areas the trencher wouldn't dig, and those areas had to be dug by hand. Then there's the (not so) little matter of making sure the trench is clear of loose dirt with a steady grade. All in all, it turned out to require seven days (a few hours each day) of very tiring work.

Our plan was to install a 6" wide trench, but the only one small enough to maneuver behind our house was at Home Depot, and they require a 3/4-ton truck to rent it. That's primarily because there's a TON of extra accessories they give you with it, and altogether it weighs a LOT. Because I couldn't round up a truck, I had to go with a 4" trencher from Sunbelt Rentals.

Using the trencher wasn't *too* bad, but you do have to manhandle it a bit. I wore a nickel-sized patch of skin off my palm trying to get it unstuck from the soft dirt a few times.

We had bought a bunch of 4" socked pipe and fittings, but they wouldn't fit in the trench, so we took everything back and got 3". Unfortunately, Home Depot doesn't sell socked 3" pipe, so we had to sock it ourselves. If you think this sounds easy (like I did), try socking 100' of pipe sometime. It's not particularly difficult, but it's awkward and takes a long time.

So... here's what we did to install about 200 feet of trench. First, we dug the trench with the trencher. This included extending the shallow trench for our driveway drainage pipe we started this summer.

Then we dug by shovel and hand where necessary and cleaned out all the loose debris, including countless large rocks.

Then we compacted the bottom of the trench with a 4x6.

Next we laid landscaping fabric in the bottom of the trench, followed by a 1-2 inch layer of gravel.

Then we put the pipe on the gravel, checked again for grade, and covered the pipe with gravel to within a few inches of the surface.

Finally, we put another layer of landscaping fabric on top and covered the whole works with dirt.

We worked in roughly 20 foot sections to cover the trench as quickly as possible so we didn't have to worry about cave-ins, etc. When it was all done, we moved a lot of dirt around to increase the surface grade away from the house on all sides.

Now we wait for the rain. We didn't get as deep as we wanted on the entire trench, but I've read success stories from folks who dug shallower trenches. For now, we'll remain hopeful that this will prevent water from making it to the crawlspace, or at least keep it to a much more manageable level. It's supposed to rain again next week, so stay tuned.

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