Coachroof fiberglass repair

[Jim Walsh]

Since I have owned Orion she has had two areas on the coachroof where the fiberglass laminate had been compromised. The pre-purchase surveyors report had noted them and said they were not structural but should be repaired to ensure water could not compromise the balsa core. His hammer had given no indication that there had been any water intrusion but two hollow spots were evident. Both areas were about the size of my fist and each had lifted about a quarter inch, with no actual break in the gelcoat.
It took thirteen years for those two spots to irritate me enough to take remedial action. I didn’t want to make a mess so I hired the local fiberglass pro to do the job properly.
First the hardware adjacent to the areas was removed, a stand-up single block and a single turning block. A meaty square shank screwdriver and a 12” crescent wrench successfully removed the fastenings....thankfully. Next the pro used a soft mallet to check for hollow spots on the entire coachroof. He found no indications other than the two which were noted initially.
Now it was time to get the angle grinder into the act to open the two spots and see for certain that there had been no water intrusion into the balsa. This was the most nerve racking part. After the areas were fully exposed it was clearly evident that the surrounding balsa was dry as a bone....hooray! The areas were then ground to a bevel in preparation for the glass work. The aluminum backing plates for the two pieces of deck hardware were found to have a coating of dust which the pro said was an indication that the surfaces had never been keyed properly so the polyester resin and subsequent layers of glass had never bonded to them. At some point the fastenings for the hardware had allowed water to migrate between the top surface of the backing plates and the fiberglass. It was likely the pressure from freezing that had buckled the surface at some point.

[Jim Walsh]

We managed to wedge a pry bar and a couple stout screwdrivers under the edges of the backing plates but they were both firmly attached. The backing plates were very substantial, at least 1/2”, perhaps 5/8”, The surfaces of the backing plates were aggressively keyed with the angle grinder to promote a proper resin bond. The areas were liberally coated with polyester resin and it was allowed to get tacky before the polyester soaked fiberglass was applied. Since the deck hardware was going to be reused and the threaded holes in the backing plates were in perfect shape the original fastenings had been screwed in and the protruding portions were masked to allow removal after the glasswork and gelcoat was completed.

[Jim Walsh]

The glasswork and application of the gelcoat went on with no problems. It was great to watch a pro....they make it look easy. The following day it was time to mask the area and paint the surface using Awlgrip “Moondust” with nonskid added. What a pleasure it was to see the finished product. I waited two days for the Awlgrip to cure....this was done in late October, outdoors, and I was advised to not push it. Then I was able to remove the old fastenings. I retapped the threaded hardware holes just to ensure there was no dust in the bottom and used a shop vac to remove any detritus.
A buddy had some Marelube TEF 45 so I coated the threads of my new replacement fastenings and bedded my original hardware in Lifecaulk. Woo hoo....job done!

[John Stone]

Great work. Very professional. I bet you’re glad to have that behind you. Will you erect your winter cover or is that already completed?

[Jim Walsh]

Great work. Very professional. I bet you’re glad to have that behind you. Will you erect your winter cover or is that already completed?

My winter cover went on as soon as this was completed. That’s why the last photo has a slight green tint.