Bumps on inside wall

[donkro]

Anybody know what this is? Bumps are forming in a spot on an inside wall next to the bed, below a window of my Coachmen Class C 27QB. They are hard, not likely a water issue, no water stains.

[hstrymkrs]

I have found that to be from water/moisture getting in the area above it. Mine had that when the window seal was leaking and when the range hood vent was leaking. Neither had water stains on the inside, but they were leaking as the outside was delaminating. Others might have different ideas, but it might benefit to check the window seal or pull the window and reseal it.

[donkro]

thanks, any idea what's behind the wall surface, what it's made of?

[hstrymkrs]

I am not 100% certain what is behind your wall. Others might now more about your model. From what I have read there isn’t much to do inside other than find the leak and repair it. There is a thread on here where people are talking about that specific problem. Do a search for it. If I find it, I will post a link to it. I am sure someone with your style/model camper will be able to enlighten us on its construction. Mine is made of metal frame with wood support, laminate and fiberglass? covering. The inside is just a Luann board. Those bubbles are where moisture got between the outer cover and the luann, I think. That one thread explains it much better than I can.

[CC38EL]

I'm pretty sure your wall is made of Azdel. In our 2017 27QB, we had the same bumps but they weren't moisture related, as in a leak.

I never could figure out where the bumps were coming from but they were on all the walls in various places. Hard as a rock....so I was thinking some kind of oozing started during the manufacturing process and accelerating as it aged.

Sold the RV before I got too curious.

[007matman]

We had them on the back wall of our old RV. Same deal. I never 100% confirmed the reason other than there was some repairs performed around the clearance lights/new sealant in the past.

The PO told me had used the camper in cold weather and the kids had placed posters on the wall. They pulled them off when they went to sell it and the bumps were there.

My guess here is that it was either due to the leak that was repaired or the posters trapping moisture. Honestly, wit the er sounds like a possibility.

Do you use the camper in cooler weather? If so, you might want to add a dehumidifier. Moisture is a real problem in these RV's.

[ependydad]

It's a water leak. Look above the area for a screw or other intrusion that's letting water in.

I found this in my awning rail. Apparently the factory worker missed and made a second hole. They slapped some sealant in it but it shrunk and fell out. But frustratingly, it was behind a piece of trim and I couldn't see it until I went searching.

There were NO other signs of water intrusion- no stains, no soft spots, nothing.

[Palinduff]

That could be mould.

[hstrymkrs]

Here is what mine looks like under my window and under my range vent hood. I found leaks directly above them both.

I removed and resealed the vent, and I removed and resealed the window. All seems to be good now. Just trying to prevent yet waiting and watching for the next leak to occur.

[dbrookinssr]

Those ARE mold pockets, I had them behind my sink in bathroom. We live in GA so a lot of humidity. I actually cut the pockets, scrapped the mold out and sprayed with bleach. Covered that area with the stick on splash guard. I do keep my unit plugged in now when not in use and run a dehumidifier.

[hstrymkrs]

Good to know. I will put that on the list to take care of it.

[NJBreeze]

For sure the window is leaking. Pull it , replace the tape and then also caulk around the top.

For those with new trailers and I guess even older trailers go and throw a bead of caulk around the top of all of the windows.

[BDenn]

When my Coachmen was new. I got concerned about water leaks when I tap on outside of window frame and it moved. I sealed around everything used flex shot has silicon in it. Maybe should have used Proflex clear. 3 years still looking good. fingers crossed.