Slow down / stop fiberglass crack?

Usually it will, around 1/8 of an inch and try to catch the end. If successful you can go back later with epoxy to fill and lock it.

Is it really fibreglass or a formed sheet plastic product?
If it is fibreglass it looks like it just the gel coat. Cosmetic.

I would also check for unwanted movement when the slide is out. There may be an underlying problem that is causing the skin to flex.

Cosmetic damage - do nothing or paint with fiberglass resin with white pigment added.

Deeper crack - fiberglass tape soaked in resin, either from inside (less visible) or from outside (then add white pigment). This will fix it forever.

Right now - do nothing or drill 1/8 hole, make sure you don't drill deeper than necessary.

Yes, could be underlying damage causing this crack.

You definitely need to do something with it. I have seen similar cracks let in enough water to do a lot of damage.

If this is the front slide on a 5th wheel you may be experiencing frame flex at the pin box causing the crack. The welds connecting the pin box to the floor may have broken and is allowing flex across the floor platform. If so google frame flex on the pin box and you can find utube videos on how to determine if its frame flex or not.

joebedford wrote:
The side of the rv at the rear of the bedroom slide has very recently developed a crack. Will drilling a hole at the end of the crack help?

What size drill?

Before fixing it you should find out the reason why its cracked and fix that first,,

If you just are worried about the structural aspect, yes, drilling a hole often will stop the propagation of the crack.

The problem is, water infiltration and rot are the bigger concerns.

I'll give you 10-1 odds, this is beyond the gelcoat. Hard to say exactly what caused it until you open it up.

I posted last summer that when we unhooked in Nashville on our eclipse trip that the front end of the rig / hitch made a horrible groaning / creaking noise. Unable to get any professional help, DW and I pulled off the fascia around the pin box to look for broken welds, etc. Didn't find any. Really ugly welds, yes, but broken, no. Ultimately we decided it was the Reese hitch pivot that was bare metal to bare metal. Grease that before each trip - no more groaning.

Anyway, I digress but when I had the fascia off I didn't see any breaks for wall support. I DID see screws supporting the fascia screwed into the edge of plywood, but that's another story.

There has always been a lot of flex in the front end of my rig. In fact, it came from the factory with a gap in the exterior wall covered by a piece of plastic trim at the front of the front slide in the same area as the new crack at the back of the slide. I always assumed that gasp was to allow flexing. My guess is that 7 years of flexing has finally cracked the wall in a new place.

I'll drill a hole and watch it on our 1900 mile northbound migration starting in a few days. I'll let you know what happens.

Typical skin crack; below the window in the slide out at this spot. My '97 had it and drilling a hole didn't stop it. No damaged structure problems. Just a stress crack.
I dropped by my rv dealer and asked what was the fix. The service guy gave me a 10" long piece of joint molding. I cut the crack in the siding all the way down . Ran a bead of sealant over the crack and attached the molding two SS screws. Now looks like OEM.
If you notice older units and maybe some new units have a short piece of molding in that spot. The factory got smart and cut the skin at that spot and installed molding.