Extruded polystyrene sheathing as building material?

[cyclocross]

I was in the local Home Despot and looking at some 2"x2'x8' extruded polystyrene sheathing and thinking "wonder if I could carve a board out of that?" I've seen a couple of blogs where people have done this and it seems like a cheap way to try shaping a foam board, especially as a first timer. I want to build a 14 foot board for here in the Puget Sound. No real waves to speak of but definitely plenty of chop and headwinds. Somethign like a Bark Dominator but maybe a touch wider and with a bit more of a kayak nose to it. I was thinking I could rip a sheet in half and epoxy it to a full sheet to give me a 3'x8' sheet. I could then put to of these together to make a 3'x16' sheet and then stack 2 of those together. I'd also epoxy in a 1" thick sheet along the top for more volume. I'd alternate how their stacked to avoid any continuous seams. At $20/sheet I'd only be in for $140 to give me a blank big enough to make a 14' long blank. Is this crazy? Anyone here go this route? Issues to be aware of? Best epoxy to use?

[PonoBill]

Sure, but you can get a block of EPS big enough to do four or five boards for the same money--all in one big piece.

[Dwight (DW)]

Living near water, you should be able to find someone local who sells EPS block to dock builders. Here, that place is the beach hardware store. They stock 2'x'2'x16' EPS and it sells for only $76

EPS is safer than extruded foam. Extruded can have issues with delam.

[cyclocross]

Thanks for the tip, I live just a mile from the fishing docks in Seattle so I'll see if there are any maritime supply shops that can supply a 14' piece of foam.

[PonoBill]

Try insulfoam in Kent, they have all kinds of EPS: http://www.insulfoam.com/