Question on plywood and other Matl's.

[RickK]

Lowes sells kiln dried marine ply - $80ish/sht

[kaptainkoz]

Rick, its not so much the kiln drying as it is the chemical "pressure treating" that makes this wood virtually rot proof supossedly. Thats my attraction to it to not have to worry entirely about making everything 100% waterproof... which we all know is practically impossible. It seems like a great product for a floor

[kaptainkoz]

Wingtime... yes thats the one. I have seen that site as well. Im looking for someone that has actually used it a long time ago to let me know how its holding up.

[kaptainkoz]

Im thinking that if I were to use the Greenwood PlyDek XL for my floor, I wouldnt even have to encapsulate the underside of the floor. Not only is the wood chemically rot resistant, but leaving the underside open would allow it do dry even more should there be some sort of breech allowing water to get in.
Im pretty set on going this route. I have heard and respect the arguements about using basic materials or AC fir, but this plywood seems like a great way to go to add one more layer of assurance of it not happening again.
I have looked into Nidacore but aside from the price, its just too involved for me to get a screw to hold well. I also looked into Coosa which I liked much better but the cost is over 3 times thats of ply and it too has "less than ply" screw holding ability. I need 5 sheets.. I cant see spending $1,600 just on Coosa.

[kaptainkoz]

I called Tony Pieper - Marine Sales Manager - Phone: 800-698-6041 for Greenwood, and he assured me that fiberglass sticks just as well to the XL. He said the primary sale of that plywood is for glassed over decks and no one has had any issues.

Im planning on getting started in the spring so ill let everyone know over the next few years how it goes!

[wingtime]

I was going to suggest you give them a call to ask them just that!  Great find!

 I'm not so sure about not laminating  the bottom of the plywood. Most  bilges I have seen are very damp and nasty.  Also the bottom layups are put under tension when a load is placed on the deck adding considerable strength much like a truss.

[gran398]

Koz, that last sentence sounds like me hey, at least you're honest

The benefit of a coat of something underneath is the wood isn't inundated with moisture 24/7 from the bilge. The plys may not rot so easily...but they can delam.

Many folks just roll on a coat or two of poly resin...but glass would be better, as Bruce mentions.

[kaptainkoz]

Wingtime, I didnt think of the structural aspect of it working truss like, and true about the delam. Ok, im sold, i will glass the bottom with  a biaxal coat or two and some Vinylester resin.

[RickK]

When I replaced my foor in the 170 14 years ago I sealed the bottom of the plywood (5/8") with poly resin and it looked like the day I put it in, when I tore it out a few weeks back. I may put some 1.5oz mat on it this time to beef it up - the glass is cheap enough. Maybe think about going with 5/8" to save some cash and add glass to the bottom to beef it up. Obviously you're going to glass the topside. Either way you'll end up with 3/4" or more anyway.

[kaptainkoz]

RickK,
Turns out that i am kind of stuck with the 3/4 if I want to go with thew Greenwood XL as it is the only thickness that Overtons carries. Greenwood does not sell by the piece. He gave me a distributor in SC  "service industry supply" in Wando SC that carries 1/2, 5/8, and 3/4 but I am yet to call them and see what their deal is. He wasnt even sure if they were a retail distributor. Either way im okay with the 3/4. The 20 or so weight difference for the 5 sheets isnt going to make a difference.