Pressure Treated Plywood?

[RickR]

A friend has a 1996 center console with a very soft floor (not a Donzi)
A local fiberglass man wants to use pressure treated plywood for the repair ($4500) instead of marine plywood.
Has anyone every heard of going that route?
I vaguely remember someone telling me Pressure Treated will rot in a anerobic atmosphere? Like if you paint it or encapsulate it with fiberglass.

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RICKR
mailto:riggerb@aol.comriggerb@aol.com</A>

[Len]

Rick...these guys might be able to answer that for you...
http://www.greenwoodproducts.com/Default.asp?page=2

[Stromer]

Rick,
Go with Marine Ply because it is more dense and does not have the "air voids" of pressure treated or normal ply. Even encapsulated in glass and resin, the voids are an area where moisture can develope. That's why the dense marine ply is better - much less air voids!

[Tselby]

Rick..Dont use the press. treated ply. I've heard that it has a chemical in it, that will react to epoxy and wont let it cure.

[BigGrizzly]

Most pressure treated chemicals are a natral releas agent for epoxie and other reasind, they are a oil alcline base. It will soften if encapsulated. It is already wet thats one reasion it is so heavy. Don't do it I did it once instead of asking, the glass pealed right off. in lest than 6 months.

Randy

[RickR]

Thanks for the help guys.
We are working of getting a new deck from the factory.

Len
Sounds like a great product. Nothing like a lifetime warranty including labor.

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RICKR
mailto:riggerb@aol.comriggerb@aol.com</A>

[Forrest]

Marine plywood is in-fact pressure treated using mostly the same preservatives as found in pressure treated wood that you buy from Home Depot. The only difference, besides the marine version has less voids and maybe better glue, is that the pressure treatment is of much greater density than that of pressure treated construction plywood. The big problem that you run in to using pressure treated wood of any type, is that in addition to the treatment chemicals causing bonding problems, is that the wood almost never completely dries out. Boat manufactures don't use standard marine grade plywood, but rather they use an extremely dry wood that will readily soak-up resin. That probably explains why so many boats less than ten-years old get soft or rotted out floors and decks. Many boat builders, including some well know names, simply lay a sheet of regular dry exterior-plywood over the top of the hull stringers and then glass over it. The wood is not at all encapsulated and the entire underside of the floor core is exposed to the water in the bilge. Donzi and other quality builders whether using plywood or Baltek, totally encapsulate the wood coring, which in theory should not rot until someone drills a hole allowing water to get in. So what does all of this mean to your project? I use both pressure treated and dry exterior plywood to replace floor coring in boats. Generally, if the coring is to be totally encapsulated, I'll go for kiln-dried exterior-grade plywood, but if it going into boat where the floor core is directly exposed to bilge, then I'll use the pressure treated stuff and let it dry in the sun for a few weeks prior to use. Is there still some moisture in it? I'm sure that there is. But it works just fine in cases like this, and no doubt, will out-last the factory job where they used some kind of chip board (very common, BTW). Generally, marine grade plywood is just too expensive for these applications. So where would I use marine-grade treated plywood? How about when it comes time to replace the factory all-plywood (no fiberglass at all) floor in my 1972 Magnum, which BTW, is still good.

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Forrest

[This message has been edited by Forrest (edited 05-17-2001).]