need to slightly raise deck surface

Jeremy Hillary Boob, PhD · 08-31-2009, 11:40 PM

On part of my redwood deck I'm going to remove the surface and replace it with plywood. The plywood will then be coated with a waterproof surface so that I can use the area below as a carport. But there is one slight problem... I'd like to raise the plywood deck surface slightly (like 1/8" to 3/16") and I'm not sure how best to accomplish it. In other words, I want the plywood surface to be slightly higher than it would be if I were to attach it directly to the joists. Any suggestions? Thanks.

**Termite** · 08-31-2009, 11:59 PM

Treated lumber furring strips can be nailed to the top of the floor joists before you lay down the plywood. Cut them on a tablesaw out of 2x4, 2x6, or whatever is cheapest. Problem solved.

Now, plywood? Outdoors? It will not hold up. Even treated plywood doesn't last outdoors, it isn't designed for it. The wood may not rot if you use treated plywood, but it will certainly delaminate. At the very least, a good bitumenous rubberized membrane of some sort (or even rolled roofing) is in order underneath the decking to make the carport a little more water resistant.

itsreallyconc · 09-01-2009, 05:47 AM

'mite, we've used this product successfully on ply decks - http://concretecoatingsofgeorgia.com/gulf_synth.htm -

agree w/your plywood comment however marine ply's another factor,,, nevertheless, we've used gulf & i'm always a skeptic,,, no financial interest other'n they've got a good product, imo

spray, roller, or brush. & even comes in colors,,, pedestrian traffic compatible altho no experience w/auto.

Jeremy Hillary Boob, PhD · 09-01-2009, 10:44 AM

Quote:

Originally Posted by thekctermite

Treated lumber furring strips can be nailed to the top of the floor joists before you lay down the plywood. Cut them on a tablesaw out of 2x4, 2x6, or whatever is cheapest. Problem solved.

Now, plywood? Outdoors? It will not hold up. Even treated plywood doesn't last outdoors, it isn't designed for it. The wood may not rot if you use treated plywood, but it will certainly delaminate. At the very least, a good bitumenous rubberized membrane of some sort (or even rolled roofing) is in order underneath the decking to make the carport a little more water resistant.

Thanks for the suggestion. No table saw, so it'll be a challenge cutting these with my circular saw, but I think I can manage it.

As for plywood outdoors, it'll be coated with a polyurethane system designed for just such an application:
http://www.cadeco.com/productfiles/S...-Sonoguard.pdf
The result is a walk-on waterproof surface. In fact, several of my neighbors have used this (or similar) systems with great success. Btw, it rains a lot around here in the winter (N. California, in the redwood forest), so I don't think it's any fluke that these have held up well over many years.