Waterproofing a deck to protect the sub facia (or not?)
Newbie here and in the design/go stage of hiring a GC. Our will house will be built on concrete block columns 12′ above grade. The entire back side (61’x10′) and left side (47×9′) will be covered porch, which we currently plan to use pressure treated deck boards as the floor. (as well as the floor joists being pressure treated). The roof above the deck/porch will be 11′ tall.
We’re discussing this project with 3 prospective GC’s and hope to decide on one of the 3 in the next couple of days. (Waiting on the last one’s bid, etc), so this point has been discussed but still up in the air.
For the ceiling of our “ground floor” (which will be wide open carport/recreation area), we want to have a ceiling. Most of that area being the floor of the house, but 1033 square feet of it being the above mentioned “porch/deck” area.
My SO deems the ability to see floor joists above as unsightly and unacceptable, therefore the challenge. I’ve seen waterproofing systems on youtube, which between labor and material, which seem relatively expensive, and still have potential failure points to trap water.
My proposed idea is to use a metal product such as metal roofing material under the deck with no waterproofing. At a slant, and allow it to drain, and “hopefully” create enough airflow that allows it to dry.
Thoughts, suggestions, tips? Thanks so much for your time, and attached is the elevation plan just in case that helps to picture my situation.
Replies
There are lots of products you can coat the top with that work well, GrailCoat is one. You can also put metal under the deck and slope it which I've done several times but I've had leaks both times which I attribute to installing the roofing from the bottom.
Thanks Florida. I'm thinking my biggest concern is any water holding in/on the floor joists, so I was considering coating the joists with some waterproof material, as well as the beam or facia that will see some of the water as it travels down and out of the ceiling material. I'll look into GrailCoat.
Any other comments welcome.