Most delamination occurs from leaking. I had one motorhome delam below a window. The area was about 8" oblong. I drilled several holes along the delam area and injected a resin type glue recommended by my boatyard that supposedly would not melt the poly filler. I had pulled the rig close to a tree. I put one piece of 2"x10" along the delamination area and blocked the 2x10 tight between the rig and the tree and left it for two days. I did all this after resealing the window. All needed then was a little filling work to repair the small holes. It worked fine - - could not see it.
2003 Dodge HO 6 speed Laramie Dually, Jordan controller, RDS fuel tank, Air Ride 25K hitch
Carriage 36' fiver, Onan 6500, Prosine 2K inverter, 3 slides, MORyde IS and Kingpin