Are you upgrading to another Class C, or moving to an A? Your post wasn't clear.
Newmar coaches are built with what they call "hung walls". This is a process just like building a house. Aluminum studs support an outer wall and an inner wall. The inner space is filled with insulation. It can't delaminate because there's nothing laminated in the first place. They've been doing this for many years because its the best way to do it, even though its more labor intensive. As far as I know, the only other manufacturer using this method is Entegra. (When they started a few years ago Entegra hired a few mfg managers away from Newmar.) Its also, IMO, a stronger structure, and I can tell you, my coach is very comfortable because its so well insulated-- cold weather or hot, doesn't matter.
John & Diane, Fulltimers. RVM103 NHSO
On the road since June '12 with Lincoln, the guard cat.
2002 Dutch Star 40, Freightliner, Cat 3126, 2004 Element