Flat Deck Waterproofing

Water rarely enters directly above the stain you can see. It usually gets in at a wall junction, a door threshold or a railing post, then runs along a joist until it hits a low point or a light fixture and drops. The membrane in the middle of the deck is often intact. The leak is at an edge.

Sometimes, but only if the existing membrane is well bonded, compatible with the new product and sitting on sound plywood. Coating over a failed layer traps moisture and the new work fails at the same rate as the old. We cut test areas to check adhesion and check the sheathing for softness before recommending a recoat.

A flat deck should still fall toward its drains, commonly around two percent, or roughly a quarter inch per foot. Ponding matters because water that sits for days works at seams, holds dirt and encourages moss that holds moisture against the membrane. A puddle after rain is normal. A puddle two days later marks a low spot that should be built up.

Yes, provided the finish sits above the membrane rather than being fastened through it. Pedestal pavers work well because water drains beneath them and the membrane can be inspected by lifting a few. Glued tile and turf laid tight to the surface hold moisture and hide problems. Nothing should ever be screwed into the deck after the membrane is on.

We serve British Columbia, Alberta and Texas. Our core service area is Metro Vancouver, including West Vancouver, North Vancouver, Burnaby, and Langley.