PIPE Although perforated black plastic pipe is available at home centers, I chose a 4-in. white PVC pipe for its additional strength. Black pipe also has small holes, whereas I drilled three 3/4-in. holes every six inches along the PVC drainpipe, which I reasoned would be less likely to clog with silt. Note: a high-torque drill comes in handy to power the spade bit. I joined two lengths of PVC pipe to form an 18-ft. drain that extend- ed from the stair landing all the way past the edge of the foundation wall. The pipe can be joined using PVC primer and PVC cement. After applying an end cap to the “starter” end of the drainpipe, I covered the pipe with a fabric pipe sock.
GRAVEL I used a garden hose to rinse the fine particles off the drainage rock (gravel roughly an inch in size), so it wouldn’t gum up the pipe sock. I shoveled a 4-in. bed of gravel into the bottom of the trench, then compacted it down to 3 inches with a hand tamper. The gravel bed can be used to create a slight pitch toward the daylight end of the drain ( 1 inch per 10 feet of grade). The pipe should be placed over the gravel with its holes oriented downward, so water accumulating in the trench can rise into the pipe and flow away easily. I buried the pipe in another 4 inches of more gravel. The gravel trench should be at least 24 inches wide. (My drain trench was recessed below a wider 40-in. bed I dug in prepara- tion for the 36-in. paver walkway.) Compaction is critical to the suc- cess of any hardscape work, so be sure to tamp the gravel every time you add 3 or 4 inches to the bed. With the pipe buried, I covered the gravel trench with a layer of
I lapped the plastic sheeting up the foundation wall and anchored it in place with a bed of pea gravel. The plastic sheds water along the foundation into the trench.
Place the drainpipe on top of a 3” bed of gravel and slope it away from the house. Bury the pipe in drainage rock. I covered the trench with silt screen, then covered the screen with more drainage rock.