pressure treated joists on 2nd storied deck
user-4127946
| Posted in Construction Techniques on
After 20 years of using a cedar deck I’ve decided to replace the cedar with composite decking.
My question is the pressure treated joists. The joists are in good shape with the exception of mold that can be washed off. but that’s it, should I keep them for the composite deck boards or replace them?
Replies
If they are in good shape, there is no reason to replace them.
Most composites last for up to 50 years, after you wash and dry the joists put Grace membrane on the top of the joists. It will help prevent rot from standing water. Also any joist hangers and nails or screws should be replaced with stainless.
Grace membrane is a bit expensive so I used roll roofing (not ice and water shield) that I cut into strips and gently tacked with roofing nails over each joist and beam.
That will last the approximate time it takes for the UV exposure to deteriorate the exposed paper and then you have standing water on top of joists.
"What you get is what you pay for"
It's not tar paper or something like that. It's regular roofing with granules and everything. It will last longer than any roof because the UV won't get down between 1/4 inch spacing of the deck boards.
If you don't know what you're talking about. Don't comment.
What SuburbanGuy said.
And despite popular opinion, you often DON'T get what you pay for, although you almost certainly won't get it if you don't pay for it.
Have you pulled the old decking and examined the joists? Often old deck joist will have split badly dues to rusted fasteners. If that's the case there is nothing to fasten the new decking to and new joists will be needed.