I bought a house that was build in the 70's. It has T-1-11 siding, it is a two story. There is a small cantilevered deck on the second story. The problem is that the builder did not put a flashing in bewteen the bottom of the 2nd story siding, and where the decks contacts the house. The upper deck joists actually go inside the house. It was caulked along the botton of the siding and the top of the deck boards but I've found that water still leaks down behind the lower siding. I'm considering nailing an L flashing along the bottom of the 2nd story siding, and have it extend over the deck boards to keep the water from getting down behind the top of the the first story siding. I would need to use a lot of caulk to fill the grooves of the siding. I would love to have somne ideas about how to do this in a better way. Thanks! John.