theoldwizard1 wrote:
If this is truly fiberglass, then it is built like a boat, probably like the deck/roof; resin and 'glass over plywood or foam core.
My guess is that those spots are "dry spots" where the 'glass was not thoroughly wetted. It should be repaired using the same steps you would for boat repair. It dies seem odd that a fingernail can dent it as fiberglass cures very hard.
(snip)
The roof is not constructed like a boat's hull, but rather has a thin layer of fiberglass which is bonded to a fabric backing with a total thickness of about 0.030". When I was replacing the skylight I had to be very careful as I was removing the old caulk to not puncture the roofing material because it is quite flexible, and I did puncture it in one spot.
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