What's behind the wall board?


New Member
I guess our new to us Cardinal, Forest River has lived up to it's reputation. Last week when we used our hot water heater for the first time I smelled a real musty smell coming out of our cupboards. We have a rear kitchen and the hot water tank is under the cupboards. From what we can see after ripping off the paper off the wall board that there is a leak which we think starts at the roof in the corner and drips down. At the top the wall board has a very tiny portion which has turned black but as it keeps running down it gets wider and wider. We haven't ripped the wall paper off the portion under the sink but we know there will be more.

We are wondering if there is a vapour barrier of any sort under this wall board? We have no idea what we will find when we rip it out and are hoping to come up where it is parked prepared to get the job down.

Also I notice at the back of our fifth wheel trailer when outside that there seems to be what looks like a few air pocket in the filon. I thought maybe it was water accumulating but we took the rear light off and I tried to swish the water to that spot but nothing whatsoever came out of the holes. Is it usual to have an air pocket in the back like that or do we have more to deal with and any ideas on how to make that flush again.

Your help would be greated appreciated.
Re: What's behind the wall board?

Sorry to hear about your situation.

Your wall board is fastened directly to the wall studs. If your studs are aluminum, it is glued. If wood, it is nailed. There is no vapor barrier.

The air pockets in the filon fiberglass is delamination. The glue used to glue the fiberglass to the wood backer has come loose and the heat raised the fiberglass up. The only fix is to grind out the pocket, fill with fiberglass, smooth and paint.

Good Luck
Re: What's behind the wall board?

I forgot to say that the first thing you need to do is get Self Leveling Sealant and go on the roof and reseal where this water is getting in. Do not use regular caulking. It must be for rubber roofs. It does come in regular caulking gun size tubes.


New Member
Re: What's behind the wall board?

Grandview Trailer Sales, thank you for your time. We used some kind of caulking on the section where we figured it was leaking but it was not self-leveling. A good part of the area we caulked was not on a horizontal level but vertical where the boards meet to make a corner. Do we need to dig that all out and then use the self-leveling. Could you explain..........will other types cause serious damage or will they just not wear well?

Thank you.....you are a valuable reference to this forum and your input I know is appreciated by many of us!