any pavers or other materials that will cover the gravel. Generally speaking, the trench should be at least 18 inches deep. I recommend breaking ground with a mattock, then digging out the loose dirt with a round-nose shovel. Save the flat-nose spade for scraping the bottom of the trench and shoveling gravel. Renting a powered trencher might speed up this project, but I was working near utility lines and decided to proceed carefully and dig it by hand. Note that this project required a lot of extra digging because of the patio on top, which may not be the case in other situations. SHEETING I lined the bottom of the trench with super-duty 6-mils plastic sheeting. Furthermore, I lined the two dirt banks shoring up the trench with the heavy plastic, with one of the sheets lapping up a few inches along the founda- tion wall. The two flanking sheets were layered over the bottom sheet, forming a three-ply under- layment along the center of the drain. The sheeting is easy to cut to size with a sharp utility knife.
Line the trench with super-duty plastic.