Surfside fibreglass leak

[JasonGill]

I discovered a small leak in my trailer last night, right below the belly band. I can’t seem to see a hole or crack, either inside or out, but when it rains a small drip forms on the inside and runs down the wall, see photo. I’ve never tried repairing fibreglass, but I was going to give it a go with a small patch repair kit. My question is, should I drill a hole through the wall and then patch, or can I simply leave the wall as is and apply some new glass to the inside face of the wall? If you have any other suggestions please let let know. Ima complete beginner when it comes to FG work.

[John in Michigan]

Jason, your photo didn't show up.

If the inside surface of the trailer that you are attempting to repair is polyester resin, you can repair it without addressing the outside surface. If there is a structural crack, apply layers of fiberglass cloth or mat to the interior surface soaked in polyester resin. The surface must first be ground or sanded and cleaned. Read manufacturer's directions.

[JasonGill]

Oops, here’s the pic. Just to follow up on this, I stripped all the old caulking off the belly band to find that there was a ton of water trapped in there. The belly band on the surfside seems weird. Although the bottom of the band wasn’t caulked, the water still wasn’t able to escape through the bottom. Not sure if that’s normal for these? The previous owner had done a terrible caulking job at the top of the band, so there was a lot of water able to get in there. And of course it just kept weeping into the trailer thru the crack in the fibreglass. I spent the day cleaning up the belly band, letting it dry and then resealed the top. Hope it works!

[John in Michigan]

You can, as you propose, patch any leaks on the interior surface. However, if water is getting trapped in the center seam or joint, when the water freezes it will damage the fiberglass shell, potentially resulting in more leaking in the future. A permanent fix is to remove the exterior molding, then clean out, dry out and seal the seam with a marine sealant or epoxy or fiberglass and polyester resin.

[JasonGill]

Originally Posted by John in Michigan

You can, as you propose, patch any leaks on the interior surface. However, if water is getting trapped in the center seam or joint, when the water freezes it will damage the fiberglass shell, potentially resulting in more leaking in the future. A permanent fix is to remove the exterior molding, then clean out, dry out and seal the seam with a marine sealant or epoxy or fiberglass and polyester resin.

You raise a good point about the freezing. I’m guessing that’s probably how the crack happened in the first place. The water that was in there probably froze and cracked the FG. In the meantime, I’ve removed all the existing caulking, dried out the belly band and re-sealed with Sashco Lexel sealant.

[thrifty bill]

I believe the Surfside design mimics the Trillium design. If so, the Trillium belly band repair is the right approach, and extensively documented here. Even a "perfect" caulk job is not the answer.