Tuesday, November 28, 2023


What can be done for RV sidewall delamination?

gary-736Dear Gary,
What’s the most inexpensive way to deal with a soft wall spot where there was prior water damage? Also, the outside has a bubble. Is there any way of smoothing it without spending a fortune?

Under our window, the day/nite shade pulled out and upon inspection we found a little hole where the wall is soft. We need to fill it in with something and patch it but are clueless where to begin.

We got the RV about five or six years ago from an older neighbor couple and didn’t really pay attention to the small bubble outside. But later on, our day/nite shade on both sides of our bedroom under the windows pulled out from the wall. When my husband went to fix it, thinking he just had to screw them back in, he noticed the small holes on both sides. Inside it is like chewed up pieces of cardboard or wood, whatever that stuff is. And the wall around it is soft – not the whole wall, only the area around it. There is no water coming in from the roof or around windows that we have noticed, so that must’ve been prior damage.

The older couple has passed away. We love our RV, but we are in dire straits financially and can’t afford to spend a huge amount of money – but we need to repair it. Is there a filler we could put in the holes? And is there a way of straightening out the bubbles outside, patching them or something we could do? We realize it may not be perfect but we want to try to at least get rid of most of the bubbles. Thank you kindly for any advice you can give me. —Angie L.

Dear Angie,
This is a tough one! You apparently have what’s called sidewall delamination due to water intrusion. Unfortunately, water intrusion causes the most structural damage to RVs – especially if repairs aren’t addressed immediately. The normal repair in these instances is a complete replacement of the entire sidewall – quite expensive and usually only attempted by the manufacturer or a very-well-equipped service center. It is certainly not a do-it-yourself project, unfortunately.

There are a couple of things you might attempt, but it will in no way allow you to regain the original strength or integrity of the sidewall. Since it’s located under a window, you do have some hope, however. It will necessitate the removal of the window. (Visit this page for information about removing and reinstalling a window.) Once the window is out, peel away all the rotted paneling, insulation and structural members that have been destroyed. Once you reach “good wood” or non-damaged adjacent sections, trim and square the inside paneling. What you should now have is a big rectangular gap inside the RV where the damage used to be. You should be able to see the inside portion of the external bubble on the outside of the coach.

Next it will be necessary to secure and cement blocking wood directly over that bubble from the inside and make sure it covers beyond the bubble on all sides and connects to the first structural members of the “good wood” you originally exposed. Apply the appropriate type of glue and clamp the block in place through the window to flatten the exterior bubble against it. This will require some large C-clamps. Place a thin piece of protective plywood temporarily on the outside wall between the clamps and the sidewall. Once that cement has adhered, it should have eliminated most if not all of the bubble. It may not be possible to eliminate all of it. You may want to add additional blocking inside the wall void where the mounting screws for the shades will be located and blocking to attach a new section of interior paneling.

Once the clamps and temporary blocking are removed, all that’s left is to add insulation and a piece of interior paneling that matches. Trim the new paneling piece to match the cutout you made when removing the damaged, soft wood. You can add flat trim strips to cover the joints between new and old paneling.

You won’t gain much structural integrity, but it may eliminate most of that exterior delamination bubble and provide solid mounting support for the shades. This is the only thing I can think of, short of replacing the entire wall. Be advised, however, that once degradation begins, it’s likely to spread and further delamination may become evident. Hopefully the previous owners stopped the leak and the water intrusion was minimal. Good luck!

Read more from Gary Bunzer at the RVdoctor.com. See Gary’s videos about RV repair and maintenance.





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Kevin (@guest_22472)
5 years ago

This can certainly be a difficult job but one that can be done by those with “jack of all trades” or construction skills. I’ve just c ompleted the tear out of walls, roof and floor of a slide out and complete rebuild. The most frustrating thing was finding a suitable glue for the fiberglass panels. Camper supply stores simply don’t sell it as they assume this is not a repair to be done by the public or they want to do the work in their shop. The supplier who sold me the fiberglass panels would not sell me the glue because it is a hazardous material and he was not able to ship a HM product. But he didn’t offer to help me obtain it directly from the manufacturer or another supplier nor did he help me find an alternative. I spent hours searching for a glue that would serve the purpose. After much research, I finally settled on Silkaflex-252 which is a product used in the marine industry and is readily available. Only time will tell if my hours of research and many weeks of construction will pay off or be a futile effort. If you would like to see my project, I have pics available on request.

Bruce (@guest_22595)
5 years ago
Reply to  Kevin

Hi Kevin, yes I would like to see your pics. I’m also in the middle of a 5th wheel rebuild. I’ve removed the slide out completely, replaced it with a fixed wall (the slide out exterior wall permanently attached) and two sections of wall that have delaminated. I’ve removed all the damaged wood and have cut and fitted pieces of 1/8″ sanded sub floor to replace the original exterior wall. I had considered using fibreglass epoxy, Pl premium construction adhesive or Dicor sealant.

The epoxy and the construction adhesive I thought might be too rigid but I wasn’t sure if the Dicor would be strong enough. The project has been on hold until it warms up, maybe in the next couple of weeks if we’re lucky, but its snowing again right now.

Albert (@guest_22397)
5 years ago

I, personally, would try to inject “Get Rot” into the thoroughly dried areas. Get Rot is a resin that hardens harder than wood, but can be sanded, drilled, nailed and screwed into. It is made to restore dry/wet rot in wood. Most hardware stores carry it.

Bruce Brownell (@guest_22323)
5 years ago

What would be “the appropriate type glue” to bond the exterior fibreglass to the new paneling?

Kevin (@guest_22471)
5 years ago
Reply to  Bruce Brownell

This is the catch 22. You can buy the fiberglass panel but no one will sell you the glue. It’s either extremely difficult to find, not sold to the public or not shipped because it’s a hazardous material. After much research, I finally settled on Silkaflex-252. It came in a tube like caulk. It is very thick and requires a lot of work to spread thinly. Time will tell if it will hold but it is made for the marine industry so I expect good results.

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