Detailing Decks Over Living Space
When the roof pitch is shallow enough to walk on, clear drainage paths and careful waterproofing are essential.
Synopsis: This short article examines a deck built over a living space at a Florida house, with tips for protecting the structure from leaks.
Charlie and Sally Williamson’s lot on Apalachicola Bay looked plenty big until I saw the wetlands survey. I realized then that we would have to build up instead of out. But a multistory house meant two decks built over finished interior space, an architectural bugaboo I always avoid. However, Charlie is a construction waterproofing consultant. We discussed the situation over a few beers and decided to damn the torpedoes and go full speed ahead.
The best roofing materials can still leak when they’re applied to a deck that holds water, or ponds. So good waterproofing begins by sloping the deck at least 1/8 in. per ft. to dram the water; 1/4 in. per ft. is even better. On Charlie’s house, the carpenters sistered 2x6s to some…