underlayment for aluminum skin. delaminate? rot?

[sean]

I plan on using 1/4 ply under aluminum skin. Should I glue the aluminum to the ply? How do I prevent delamination? Do I need to worry about moisture getting between the aluminum and the ply? Any way to treat the ply so it wont rot?

[madjack]

Sean, we chose to float the skins rather than using adhesive...we sprayed a couple of coats of poly on the ply for sealing before applying skins...you are insulating the roof...aren't you...that will help to cut down any condensation under the AL
madjack

[asianflava]

You can if you want, I glued mine because it was easier to handle. I did nearly all the work by myself. It may delaminate but there are enough places on the body to hold it down if it does. So far mine is staying put.

In hindsight, I probably would have gotten away with just using 1/8in ply under the roof. I used 2 layers of 1/8in ply and staggered the joints to prevent leaks. Well, as Cedar Hill taught me, leaks come from everywhere. I only have 1 layer of 1/8in on the sides.