I need to replace at least part of my roof on a 1980 KAYOT. It looks like 1/4 inch plywood on the top and bottom with styrofoam in the center. The roof is ten feet wide and no supports except on the outboard edges!
This must be some really strong stuff, however I have no idea where I can get it. Would anyone have any suggestions? Thank you.

This stuff can be tough to get because in most older houseboats each manufacturer had a manufacturer of paneling and other items provide them a captured line that no one else could get. When that houseboat manufacturer goes out of business you are generally out of luck for exact replacement. You may be able to make up what you need by using blue stryrofoam insulating board that you can get at most home centers or you might be able to use the foil covered foam insulating board at most home centers. I believe the styro is available in 1 in. thickness and the foil stuff is 1/2 in thick. You might try urethane glue to bond the plywood and foam together. Most other glues have petroleum _base_d solvents and will attack foam. I know you can get foam of many different sizes through aircraft supply houses such as Wicks and Aircraft Spruce and Supply. This foam is usually urethane _base_d and can be epoxied to wood or fiberglass but it is kinda pricey. You are right if you bond foam between two pieces of wood or fiberglass it is very strong, this same technique is used in many high performance aircraft wings. Hope this helps.

Thank you Joe, I will check into all of that. I would like to go back as original as possible and I used to be an aircraft mechanic at one time, so will contact some old friends to see about that foam. Kinda like the foam they use in fuel cells of the military aircraft I would assume and I know that stuff is tuff. I've put a lot of money in this old boat, but I sure love the thing.
Plan to redeck it in a few weeks if I can get the 10' plywood!
Thank you again for the information and hope you have smooth waters.
Bill

Try gougian brothers i dont think i spelled that right or contact West Systems epoxy they can get you in touch with them they have all the things you need. Have fun, Hayseed