# Build a deck/carport



## jaums (Jul 11, 2010)

I'm considering adding a deck that would double as a carport. It would be for 2 cars with a door from the upper level of my house out to the deck.

Obviously a traditional wooden deck has the problem of rain dropping between the slats onto the cars below.

My first thought is to pour a cement slab, suitable for cars, build a traditional wood deck with a sort-of roof under it, slanted away from the house.

My second thought is that this is like building 2 surfaces and it would be less complicated and cheaper to build just one surface that would serve both purposes: a deck for people to walk on and that would protect the cars under it from rain.

What came to mind next was to build the frame & joists and place plywood over the joists [more or less like an indoor sub-floor], water proof it and then put a finish layer on top to walk on. This "floor" would be slanted slightly away from the house--enough to get the rain to flow away but not enough to be really noticeable when walking on it. The plywood would be painted underneath, so the "ceiling" of the carport would be painted joists with painted plywood over them. On top of the plywood put a self-stick membrane such as is used on roofs, under shingles. Then put the deck surfacing, maybe indoor/outdoor carpet or, go a step further, and put a layer of cement board and then porcelain tiles, which are amazingly cheap.

What are the weaknesses of this plan? Or is it just "all wet" and a bad idea?

Other ideas?

I don't particularly like the idea of a traditional wood deck surface--even pressure treated doesn't seem to hold up very well & the new plastic & other choices are expensive!

What do you think?

Thanks!

Jaums


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## pioneerurban (Aug 31, 2010)

Jaums,

I would go ahead and build your deck as normal. Then when you are finished with your deck. Go buy the fiberglass corregated panels and attach them under your deck to the joists. Make sure that you have them slanted away from the house, with 1 inch, 2 inch and 3 inch "shims" along the joist where you will attach the panels. Then you can attach a gutter system to the free end of the panels to catch rain water and drain everything away as normal.

I have thought about how to do this for years and this is the best, easiest and most cost effective way to keep your carport dry.

Something else to consider is when you attach the ledger board to your house for your deck is to have a 16 inch width of flashing under the ledger board and then you can bend the flashing that is exposed up and under the fiberglass panels, so that no water can get anywhere but your drainage system. 

Hope this helps, as this is my first time ever posting on a diy forum. 

I'm not a professional by no means, but I think of stuff like this all the time.... 

Good Luck!


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