New Boat Floor

[Gatores]

I was just wondering how thick of plywood would be best for a new floor in my 16' crestliner. Also if I use regular plywood and treat with a fiberglass resin will the marine carpet glue still stick to it. Thanks in advance for any help.

[Steve Bakken]

Measure the thickness of the plywood that's in it now. 90% of the time, it's half inch. We haven't had any adhesion problems in the last 20 years, glueing carpet onto the resin. If you have any doubts, run a grinder or sander lightely over the resin to give it "tooth" for the glue to hold onto.

[Gatores]

Thank you very much for the information.

[1DIRTBALL]

Steve, I've read any number of times, where both you and Valv have recommended using resin to preserve your plywood boat floors.Exactly what kind of resin is it? When I go into the paint store, just exactly what do I ask for? Do you need to do any special preparation on the plywood before applying the resin? I have a half inch floor in my boat. When it's time to replace it, I was thinking of using 5/8". Do you think that would work OK? Thanks in advance for your help. 1DIRTBALL

[Valv]

You don't have to go to paint store, the resin it's just plain fiberglass resin. Go to a Walmart, K-Mart, etc. they have it in the automotive section, very cheap to purchase.

[PierBridge]

So would marine plywood already have this resin?

[Barony]

I replaced my floor last year and put 2 coats of Spar varnish on instead of resin. Did I make a mistake doing that?

[Hotspotter]

We used 5/8" plywood on our floor on the areas that had to span more than a foot or two (casting decks). In the floor, we just ran supports underneath and put 1" pink foam underneath to provide a good tight fit with 1/2" plywood.

Barony:

We did the same thing with our boat floor 3 years ago, and I think, esp. with the spar varnish, that the carpet will wear out long before the plywood does.

Joel

[Barony]

I keep the boat covered during the summer and in storage during the winter, so I hope that there are some things that I am doing to help myself and the boat out. I really try to keep it dry when not in the water.

[Valv]

No, marine plywood doesn't have any resin, it's a rare product with no voids (air gaps) petween sheets and woods.

There is not need to get it, you can use plain 'ole plywood if you are going to cover it with resin.

DON'T use treated lumber, or it will have a chemical reaction with aluminum.

[Steve Bakken]

5/8" would be just fine as long as it fits. Some boats run the floor up to the lockers and casting decks, and some run the wood under. If your's goes under, then thicker wood will make everything sit cock-eyed. You'll need to either go with the stock thickness or stop the wood at the edge.

[Fishin4Life]

Quote:

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DON'T use treated lumber, or it will have a chemical reaction with aluminum.

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What will it do to the aluminum, I was looking at putting in a front deck over my bench seats in my 14' boat. It would only have contact with the aluminum on the edges (if that, because it will be covered with carpet). I thought maybe treated would hold up better in this case.

[Pat K]

ACQ treated lumber eats aluminum. The only metals that can come in direct contact with it are double dipped hot galvanized steel, stainless steel or deck screws treated with approved chemicals.

Because it will often be wet inside your boat the chemicals are more apt to leach out and react with the aluminum.

Since they changed from cca to acq treatment 4 years ago treated lumber shouldn't be used anywhere in an aluminum boat. Your lumber yard should have warning lables near its treated lumber that it should not be used near aluminum siding and only attached with approved hardware. We have'em, but no one reads them.

Your local building inspector probably has a sample of aluminum siding that came in contact with acq. Within 6 months all of the aluminum within 1/2" of the acq will be gone!

Two years ago I saw the aluminum bed of a truck that had only made one 350 mile delivery with a load of acq, there were divots as deep as the thickness of a dime that had been eaten into the bed where the stckers sat. New treated lumber is wet and there would be alot of heat and friction from going down the road so it would be a worst case senerio.

Do a search for Universal Forest Products. They have alot of info on their web site about how corrosive acq is. All of the info will be about aluminum siding or fasteners, but aluminum is aluminum.

Pat K

[Fishin4Life]

Thanks for the great info pat. I will be looking for marine lumber...

[PierBridge]

Quote:

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We used 5/8" plywood on our floor on the areas that had to span more than a foot or two (casting decks). In the floor, we just ran supports underneath and put 1" pink foam underneath to provide a good tight fit with 1/2" plywood.

Barony:

We did the same thing with our boat floor 3 years ago, and I think, esp. with the spar varnish, that the carpet will wear out long before the plywood does.

Joel

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Was your boat Aluminum?....what did you use for supports and how did you attach them?

I would like to raise my floor up so it goes all the way to wall instaed of having a gap along the edge.....I have Aluminum stringers......

Thanks Pier....

[Hotspotter]

Pier:

Sorry for the late response.

Yes, the boat was aluminum......for supports, we kind of flew by the seat of our pants. Basically took longer 2X4's adn 4X4's (only where needed) and used skill saw and sawzall to shape them to the contour of the bottom of the boat. We ran them the length of the boat, maybe 6 of them?

It wasn't perfect, and there was some "rocking" so we pushed the 1" foam on top of the supports, between them and the plywood. This steadied it up and makes for a great floor.

Hope this helps,

Joel

[PierBridge]

Nice..that's pretty much what I'm going to do....

Thanks Pier.....