won't protect plywood
well enough. If there are any cracks, leaks
, the plywood
will absorb water
any chance it gets. The darker the deck
color, the more summer sun will be absorbed. It can get hot enough in the plys to make steam, making even more leaks
, separating the plys, pushing moisture further into the wood. The only way to solve plywood deck
problems is cover with 2.0 RSM with epoxy
. It will last 20 years, maybe forever if maintained.
When doing new decks/cabin tops, I found it better to use 2 plywood layers at right angles. Instead of 3/4" ply, 2 layers of 3/8" ply, etc. bonded together with epoxy
. Except for Resorcinol (used in PT boat construction), epoxy is the only water
proof glue for wood.