Contractor waterproofed my deck but left the membrane flat — is this fixable without tearing everything out?
Edit 2 - thanks for all the information and support. The general consensus was to remove the sleeper frame, blueskin, black membrane and plywood above the joists. After doing that I can add the rain trex system on the joists. I’ll see if I can persuade the contractor to do that. If not, an alternative that was suggested was to attach the rain trex system on top of the sleeper frame and create channels to drain the water over the edge into a gutter.
I’ll let you know how it goes.
Edit 1 - picture 1 is the current status of the deck. Beneath the blue skin there is a black rubber membrane and then plywood over joists. Picture 2 are the dimensions of deck. Picture 3 shows the original deck with wooden rails and pressure treated boards. The area underneath the deck is what I want to water proof. Contractor removed railings and is using the existing joists.
Contractor waterproofed my deck but left the membrane flat — is this fixable without tearing everything out?
So I hired a contractor to resurface my deck and waterproof the space underneath. He stripped everything down to the joists, laid plywood, then covered it with Blueskin membrane and flashing at the ledger. On top of that he built a 2x4 sleeper frame for the composite decking to sit on.
Problem is the membrane is completely flat and level. No slope whatsoever. I only caught it this morning when I put a level on it. From what I’ve read you need ¼” per foot of drop away from the house — so for my 9ft deck that’s 2.25” I’m missing.
The way I see it there are two real options:
- Pull the sleeper frame and membrane, re-do the plywood with the slope built in, re-membrane over that. Everything drains properly.
- Scrap the membrane approach entirely and go with an under-deck drainage system (Rain Track etc) between the joists instead — let water fall through freely and catch it below.
Could he remove the sleeper frame, create another plywood membrane 2.5” higher on the ledger side - slope it to the edge and then build another sleeper frame? This would save removing the current plywood membrane layer?
For context the deck is about 9x23ft, elevated about 10ft off the ground, attached to the house on one side.
Has anyone dealt with this? Is option 1 the standard fix or is there something I’m missing that makes the flat membrane acceptable? And is this the kind of thing a contractor should be fixing on his own dime or is this within normal tolerance?