Jonathan Ochshorn: ochshornDesign.com
Driveway construction (Design-build), Ithaca, NY:
Excavation, fabric, & drainage tile.
Dale Everhart arrives with his backhoe (left image) and removes 42 cubic yards of "clean fill," which we bring to various sites nearby. In addition to the primary excavation to allow for eight inches of gravel, he also digs an additional 6"-deep trench on the side of the driveway for two parallel rows of drainage pipe. Once the excavation is complete, and before the drainage pipe is installed, we spread the woven polypropylene geotextile fabric (see SRW SS5 product spec PDF) over the clay: see right image.
We install two parallel rows of 4" drainage pipe: at the top of the driveway, the unperforated pipe bends toward our rain barrels to take any overflow to the storm sewer (left); the perforated pipe that runs parallel with the rain barrel overflow pipe is there to pick up any rain water falling on the driveway that can't permeate into the ground fast enough. I have no idea if we'll ever see any water actually exiting from this pipe, but, on the other hand, we'll never get a second chance to install it... (right)
Once the pipes are installed, we begin covering them in their 6"-deep trench with No.2 gravel. Here, I'm removing all the fine particles from the gravel recovered (recycled) from the original driveway bed: I built a simple sifting device with 1/4" steel mesh that was lying around, and we slowly work through two huge piles (left image taken from the roof deck of the addition). After finishing off the recycled gravel, we bring our pickup to the local gravel pit in Brooktondale and, four trips later, have shoveled an additional two tons of the stuff into the trench (right image). It is necessary to use the smooth No.2 stone, since the crusher run we will get for the actual driveway, with its fine particles in addition to larger stones, would not allow the passage of water and would clog up the pipe. We cover the trench with landscape fabric before the crusher run arrives.
first posted: 19 July 2007 | last updated: 22 July 2007
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