Teardrops n Tiny Travel Trailers

I am new here and have been going through the posts, they are a great resource! My own tear drop is a walk in about 16 foot with classic tear drop lines. It has been 3 months and I am getting to the outside skin. my question is about aluminum as a roofing. would 21 feet grow much in the sun? it would be glued to a plywood roof and I don't see much posts about thermal expansion.

Maybe these will help you out a little.

http://www.tnttt.com/viewtopic.php?t=7601&highlight=glueing+aluminum+skin

http://www.mikenchell.com/forums/viewtopic.php?p=31577&highlight=glue+float#31577

thanks for giving me the links. there was a vintage trailer /tear drop camper rally at the local campground and one of the builders expressed his opinion that it was the glues that never stop off gassing that contribute to the blisters. has anyone heard of this?
greg