Floor replacement question (barrier btw wood and joists) late bump and PICS ADDED

[bendellee]

Floor replacement ('91 Tracker tx17). I've heard the warnings about treated wood, but also that a barrier will obviate the corrosion--even if as simple as polyurethane.

I bought treated plywood and polyurethane'd it. But, after a little more reading (re: "new" ACQ method), I'm still not sure about it. I can't seem to find a nearby place that sells marine grade, especially one that's open weekends. But, I have an idea that needs an eval.

What if I put a couple layers of heavy duty aluminum tape on the wood (over the polyurethane), where it will contact the joists? At that point I'll have polyurethane and 2 levels of tape btw the treated wood and the aluminum.

Also, what if I coat the joists with aluminum latex primer (Rust Oleum) before install?

What say the boat wizards?

 

[Fisherball]

Re: Floor replacement question (barrier btw wood and joists)

Re: Floor replacement question (barrier btw wood and joists)

Any movement or vibration will eventually wear a hole through the tape. You will delay but not eliminate corrosion. Use untreated exterior grade plywood covered with resin & glass cloth to prevent re-doing this repair in a few years.

 

[jayyyy]

Re: Floor replacement question (barrier btw wood and joists)

Re: Floor replacement question (barrier btw wood and joists)

Any movement or vibration will eventually wear a hole through the tape. You will delay but not eliminate corrision. Use untreated exterior grade plywood covered with resin & glass cloth to prevent re-doing this repair in a few years.

X2, fiberglassing the plywood on all surfaces will keep it from absorbing water, which promotes corrosion.

 

[zopperman]

Re: Floor replacement question (barrier btw wood and joists)

Re: Floor replacement question (barrier btw wood and joists)

it's not just water. there's moisture EVERYWHERE. glassing the floor is the right way to do it. you could also do a poly or epoxy resin alone..

 

[Cadwelder]

Re: Floor replacement question (barrier btw wood and joists)

Re: Floor replacement question (barrier btw wood and joists)

it's not just water. there's moisture EVERYWHERE. glassing the floor is the right way to do it. you could also do a poly or epoxy resin alone..

You can do epoxy alone, but not polyester....poly alone will crack very quickly. You'll need CSM with the polyester resin.

 

[bendellee]

Re: Floor replacement question (barrier btw wood and joists)

Re: Floor replacement question (barrier btw wood and joists)

You can do epoxy alone.

Is that with treated or the untreated exterior grade? Also, as of now I've only got one section in, but not screwed down (I've cut the boards so tight that just getting them in place is a job).

But, as to that piece, I also put a layer of silicone down between the wood and joists (in addition to the polyurethane, primer and aluminum tape). Do ya'll think that's still not enough of a barrier, and I should just scrap my current deck pieces and go with outdoor plywood and epoxy?

 

[Cadwelder]

Re: Floor replacement question (barrier btw wood and joists)

Re: Floor replacement question (barrier btw wood and joists)

Is that with treated or the untreated exterior grade? Also, as of now I've only got one section in, but not screwed down (I've cut the boards so tight that just getting them in place is a job).

But, as to that piece, I also put a layer of silicone down between the wood and joists (in addition to the polyurethane, primer and aluminum tape). Do ya'll think that's still not enough of a barrier, and I should just scrap my current deck pieces and go with outdoor plywood and epoxy?

Hmmm, several problems here.
#1 Silcone has no place under your deck, ok for limited topside stuff.

#2 You should be using exterior grade plywood anyway, interior (even sealed isn't good for a boat)

#3 As far as the treated lumber, pesonally I wouldn't use it for anything (now some will argue that point here)

#4 All you need to properly seal the plywood deck is a layer of CSM (chopped stand mat) and polyester resin, (for the underside) and then a layer of CSM over the entire topside. You should use matt and cloth to tab it into the sides of the hull (or you can use 1708)

#5 Never heard of the aluminum tape for a boat, I know it's certainly not needed. As far as can you use it, well I don't see why you would.

CW

 

[Grandad]

Re: Floor replacement question (barrier btw wood and joists)

Re: Floor replacement question (barrier btw wood and joists)

Since you already have an investment made, how about a more substantial barrier between the plywood and stringers than previously suggested? I was thinking of roofing rubber (or shower stall underlayment, inground pond material?). It's similar in thickness to inner tube rubber and would last a very long time without wear or breakdown.

 

[Fisherball]

Re: Floor replacement question (barrier btw wood and joists)

Re: Floor replacement question (barrier btw wood and joists)

The problem with aluminum tape is that the corrosion that occurs is between aluminum & treated wood. It doesn't matter if the aluminum is a stringer or tape. The treatment used on plywood is as much for bugs as water. Marine plywoods made specifically for boat building is not treated. Another problem I see is if the piece already cut fits really tight it will have no room for expansion & will warp if out in the sun all day. Carpenters always leave a gap between pieces to allow for the wood to expand when it heats up. If you must use a barrier, the rubber idea sounds good to me.

 

[zopperman]

Re: Floor replacement question (barrier btw wood and joists)

Re: Floor replacement question (barrier btw wood and joists)

Interesting idea with teh rubber mat.. post up some pics and let us know what you decide!