Decks that shed water

Q: How can I shed rainwater that hits a second story deck? We’re building one above a patio and I’m looking for a strategy to keep the area dry.

A: Yes, there’s an approach that does an excellent job and it’s quite economical to build. It involves using sheets of metal roofing material screwed to the bottom edges of the deck joists. Use the same kind of watertight screws used to hold the metal down in a normal roofing application, overlapping the seams between sheets. Roofing screws have neoprene washers already in place under their heads to keep all water out. Also, you'll need to install strapping or shims that angle the metal roofing outwards slightly or to the side, to shed water. A slope of about 1/4 to 1/2-inch per foot does a good job. You can even have this run-off directed into eavestrough and carried away from your house.