My previous camper was a Montana and I had a de-lamination problem.
I thought sure I could fix it by injecting glue underneath. I spent a lot of money on the glue/epoxy from a boat shop. For a while I thought I fixed it but it was all in vain.
If your area is as large as mine was you will probably have to remove a section to repair it. My wood backing ws ruined due to water damage. I did not have the skills to do so.
So I traded for my MH
98 Endeavor DP, ISB275
RX300, Falcon II hitch, BB Vantage Select
VMSpc, 2002 Grey Ford Powerstroke
TST 507 w/ 10 Sensors