Repair of roof delamination
This winter found some water in the shower while my coach was in storage with the fresh water system empty. I'm not sure if the leak was from the bubble or the frame. Did a temporary fix with silicone. Note - remind self not to use silicone. Removed and recaulked skylight about 2 months ago. A few screws had no grip. After about a month decided to remove skylight and build a new one. Will post about that as another topic. Found roof delaminated in a roughly triangular shaped area on the high side of the skylight from fore to aft and about 10" toward the middle of the roof. There was water under the fiberglass as I could blow air in one of the screw holes and it would come out another hole. At first I tried to dry the area with low pressure compressed air for a couple of days. Had some sheet copper in the sun to heat the area. Thought it was fairly dry, but then it rained and got wet again. Duct tape isn't waterproof. I needed another method to dry out the plywood under the fiberglass. Made 3 vents using some plywood, PVC pipe and elbows. Drilled three 1/2" holes just through the fiberglass using a forstner bit. Stuck a short bent piece of solid #12 awg electrical wire in each hole to elevate the fiberglass from the plywood and create a void between plywood and fiberglass and it also served to locate the vent over the hole. Ran a bead of hot melt glue around the plywood base to seal it. Vents aimed in different directions so that no matter which way the wind blew, some air would move through the cavity. Put black duct tape over the area so the sun would heat it. Checked after 2 days and found a drop of water on one vent, so knew it was working. Duct tape 135 degrees in the sun vs 95 on the white gelcoat of the roof. Had sunny days for about a week and rather sure it was dried out. Used West System G-Flex epoxy to bond the delamination. G-flex is supposed to bond to damp wood but works better if it is dry. Regular epoxy would work too if dry. After mixing poured the G-flex epoxy into an empty caulking tube and injected it into the cavity through several 1/4" holes. Cut the tip of the caulking tube nozzle to fit the holes. Covered with plastic film and placed 100 lbs of sand over the area. After epoxy cured feathered all the holes down to the plywood, applied polyester resin and fiberglass mat to fill the depressions. I could only do about 4 or 5 holes at a time before the resin gelled, so I mixed 0.5 oz. resin with hardener at a time. Grind down just blow gelcoat level. Fill with gelcoat, sand level, cover whole area with gelcoat, and sand smooth with 80 grit paper, then sand up through all the grits to 2000. I didn't get the gelcoat tint to match, but it's on the roof and hard to notice from a distance. I'm thinking the whole roof needs a coat of paint as it has been a losing battle to keep it looking good and the chalky drips off the windows and sides.
Topic: Repair of roof delamination