KendaldaCosta wrote:I planned to do a woody with sandwich walls (3/4" centre with 1/8" inside and 1/4" outside) but now I'm tossing around the idea of doing an aluminum skin. If I go that route, do I still need an exterior sheet of plywood before applying the aluminum skin or can I just apply the aluminum to the middle layer?
It's my opinion that it needs to be closed in. There's a chance that water could get under the skin. (I seal the exterior plywood with epoxy. A couple of slathered on layers of The Mix will probably work as well.) I think if you didn't cover the outside of the wall with plywood, and water managed to get under the aluminum, it could be a serious problem.
I use 1/4" plywood subfloor for my skins. It's better and cheaper than 1/4" ACX plywood.
Tony