Waterproof Deck Surface

[HarryS]

I'm wondering what's the best approach to building a deck with a floor that's waterproof to keep rainwater from going through into a sunroom below the deck.

This is what I'm currently thinking:

Construct the deck joists to take a plywood deck. Cover the plywood deck with rubber roofing membrane. Then, place the deck floor over the roofing membrane. I'm thinking I could use Trex (or a similar decking) over the membrane, attaching it through the membrane with deck screws but applying the same sealant used to fuse the roofing membrane edges between the deck boards and the membrane to seal the screw penetrations through the membrane. Or, perhaps, the deck boards could simply be fused to the membrane without the use of other attachment?

I've seen this kind of arrangement, with a deck area over a screened-in porch or over a sunroom, but don't know how it's accomplished.

Anyone know how this is normally done?

[Mikepier]

There's several products out there like these:

Not sure if these fit your application, there are several more out there.

[ds_lewis]

Hello,

I'm wondering if anyone knows if the Lockdry decking is quiet to walk on since it's aluminum?

Targus

[tim1198]

I think you're on track. I'm doing the same thing and considering the same rubber membrane, except then put down 1x4 sleepers to mount the decking to. Then make sure the deck is sloped away from the house so there's no standing water. Let me know how it goes, and where the best place to get the roofing membrane, etc... tim1198