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Mike_Ehrmantrau's avatar
Oct 14, 2015

Water Damaged Wall in Class C

I purchased a 1997/8 Class C Four Winds Dutchman earlier this year. It was a little bit of a fixer upper but it seemed to be in good mechanical shape.

After I purchased it and did some climbing on the roof, I discovered that the RV had a leak at one point all along the driver's side. The ceiling and roof seem to be sturdy but the wall in the bathroom had peeling wallpaper.

My plan had been to add a rising grab bar in the bathroom for my father who has mobility issues. I figured I would need to a couple of layers of plywood to the existing plywood wall once I peeled away the bad wallpaper.

Once I pulled the paper away and attempted to fix the plywood, I discovered there is not much more than luann between me and the foam insulation. Also, I am not sure if the metal bar in the wall is the spine that holds the RV together.

Attached below are pictures I took tonight after pulling down some of the plywood/luann.

If I wanted to attach a liftable grab bar to the exterior wall, what could I attach it to?

Should I layer thin layers of plywood against the wall to rebuild the interior?

Could I attach the plywood to the metal bar in the picture via screw or rivet?

Any thoughts or feedback would be appreciated.






The metal bar is just to the left of the gap. It looks like the foam insulation was miscut 18 years ago and the gap was left behind.

  • Thank you for all for your help.
    I have started to do repairs to the bathroom exterior wall in preparation for a liftable grab bar next to the toilet.

    Indeed, I did remove as much of the luan as possible. It just was not worth saving. Unfortunately, the glue used to sandwich the foam insulation between the luan layers is very strong. There is still a thin layer of wood fibers attached to the foam.

    My plan was to remove a chunk of foam between the horizontal square tubing then fill the cavity with two layers of 1/2 inch plywood. I used PL Premium to adhere the plywood to the exterior luan and the two layers together. I then used Simpson ties to attach the plywood to the tubing.


    I then purchased 5 mm luan at Home Depot and attached it much the same way the manufacturer did. I used extra hold PL Premium this time.


    The one problem is that 5mm luan is thicker than what the manufacturer used. This created a rise in the back wall. I took some left over melamine that I plan to use on the wall and cut that in strips and placed that on the good portion of the wall on the left. The two surfaces are almost level. I also cut out the areas where the Simpson ties are connected. Placing the luan over the ties was not possible with the screw heads sticking up. I filled the notch areas with PL Premium and melamine or foam insulation, whichever was closer in thickness.

  • I did a rebuild on my class C a few years ago.

    Take my advice and make sure you dig to the bottom of problem. Don't try and just patch.

    I wrote a blogwith lots of pictures showing my work and construction techniques. Hope it helps.

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