wood floor replacement options?

I am not familiar with the 64 construction, but I know my 77 did not have a wood floor from the factory. The floor was fiberglass laid over a structural foam.

When I restored the boat in 89, I removed the fiberglass floor, let the foam dry out over several weeks in the sun, then used 3/4 marine grade plywood with a fiberglass overlay. I painted the bottom and edges of the plywood with epoxy resin prior to anchoring to the stringers, etc. So far, the floor is rock solid.

Be aware that this method adds height to the floor and you must account for this in some areas as applicable to your boat. It also adds weight, but the end result is worth the added weight. Also, marine grade plywood just means it is a structural plywood (no voids) with waterproof adhesive. It will still rot just like any other plywood, so it must stay dry. Good luck.

MArine Plywood is made with waterproof glue and doesn't have any voids. Its about 3X the price of standard. If you are going to epoxy it before installing it I would use standard good both sides exterior grade plywood.

skellum,marine grade plywood is a good choice [ for a pontoon deck ] it weighs a ton and still rot's out in a few short years.at least on a pontoon it gets air flow on both sides.
the floor on our boats is another story.
i have spent a lot of time researching this,and yes,composites are good material.
for me,i want 2 things.what has less weight and will last the longest?
exterior plywood,painted with a 2-part epoxy.
if you coat that wood especially on the edges it should outlast the best marine grade carpet you can find. and less weight in your boat. hint. after you get the plywood cut & ready to apply the epoxy. wipe it down real good with lacquer thinner.this will remove any sap/resin still traped in the wood.i made this mistake on my first board and wondered why i had fish-eyes in the finish.

I'm with Kenny G.
I've got a friend who restores old Lyman wood boats and all he always uses Laun (Spelling?) plywood and coats it in epoxy.
I re-did part of my 84's floor & seats. I had him get me two sheets of the Laun from his supplier.
(I don't think you can get it from a Home Depot type place. I think you need to go to a place that specializes in wood products?)
Mine came out great. The Laun is very dense, no voids and the epoxy seals it all up.

why would u want to use luan/cabinet grade wood.assumeing your going to glue a carpet over it.it sure wont outlast exterior grade plywood if sealed.
every day on this forum,somebody's trying to make there boat go faster than it was designed to,why would you want to add more weight by using marine grade wood ? to me,that makes as much sense as trying to use pressure treated lumber to rebuild your stringers. SKELLUM. check out GLEN-L marine designs web-site.chapter 5-lumber.
wood use and characteristics chart.
and decide 4 yourself what type of wood to use.if any at all. i can tell you from experence a 1964 CC is going to have a certain amount of saturated flotation foam inbetween the hull and the floor.it may look dry on the top.but that aint where water settles,and thats a whole new subject.
if you dont want to use wood at all.find someone with a chopper gun,and spray in a new fiberglass lining,epoxy coat that,and then glue carpet down.

I don't believe kenny g was referring to CDX which is more like pressed paper. I guess the main point to remember is to seal all sides with epoxy and then glass it in to give it more strength. The composite material is nice but about twice the price depending on the type you get. Some you can cut to size and lay it down others have to be epoxyed and glassed in.

Just to help clarify a few things;

Luan is a cheap mahogany and very a very soft wood, but there is some natural resistant to rot. However, if used a a plywood veneer, it is only as good as the wood it covers. It is used a lot a a veneer on inexpensive hollow core interior doors for a painted finish.

CDX is real plywood not an OSB, oriented stand board, which I think '79 was referring to. Both are a structrual wood panel, but neither should be used in this application. If using standard plywood, go to a BBX. Both sides are solid or plugged and it uses exterior glue. One thing to remember with exterior glues or 'exposure I' ratings, they are not meant for constant direct exposure to the weather or wet environments. They may be used in exterior applications if protected, like a soffit on a house.

Marine grade plywood is more of a structural classification than water resistance. It will deteriorate with exposure.

There are plywoods treated with CCA (or the newer treatments) to the .60 retention that are used underground in wood foundation systems. These can be very difficult to find in many geographical areas.

If looking for something that goes in once and will last as long as the hull, go with the non-organic poly-based composites.

Anyone give any thought to the cement boards used as underlayment for ceramic floor tile?

Hey yellowdog! Use cement board (aka Durock) as a ceramic tile underlayment. Just be sure to use plenty of screws and/or glue. Then simply thinset the tile directly on top of the cement board. It will last forever.