I've posted about this topic before, but still do not have a good solution. I have an 85 year old house with a front porch built over the basement. The porch decking is original (I assume) and doesn't hold paint well as it has started to rot in places. I'm going to replace the decking and have considered either PT southern yellow pine, or a composite t&g porch decking. Problem is that it needs to be more or less waterproof since it sits over the basement and receives blown snow/rain from time to time. It currently leaks on occasion. I can't put in a sleeper system since the door sits flush with the decking. The manufacturer of the composite recommended layers consisting of 1/2" exterior grade plywood, HT ice/water shield, and then the decking with silicone between the grooves. As this is over the basement should I be concerned about the decking rotting from below if I seal it up from the top? Any suggestions would be greatly appreciated.
Last edited by Old College Try; 07-04-2012 at 12:41 PM.