Help with water damage on fifth wheel

[FuelinAround]

I bought a fifth wheel and noticed some rippling in the rear garage area on the wall. I could tell the wood was soft behind it and decided to rip into the wall this weekend. The interior panel with the vinyl on it was trash. I have no concern about replacing that but I do have some concern about the integrity of the panel on the exterior. After I got the interior panel off there was insulation and metal studs. Behind the metal studs was a few layers of thin wood followed by the exterior gel coat material. The thin layers attached to the exterior were rotting and I scrapped it off until I got to good dry wood. I am now concerned about my next step. Do I need to take the entire metal wall out and bond a new piece of wood against the exterior. I have rebuilt houses, cars, boats, etc but if i am getting on over my head I'm looking for someone to tell me. I have checked the rest of the trailer and found one more soft spot on the same wall a little further back. The good news it this trailer was stored in doors until about 6 months ago (i know the guy that owned it before) so I believe most of the wood rot was newer. The insulation was actually still wet on the inside. I have had it in my shop with a carpet dryer on it for about a week now.

 

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[Rene T]

The 1st thing you have to do, if you haven't already done it is get up on the roof and find the source of all the leaks. No sense investing time, effort and $$$$ if the roof is still leaking.
You've got your hands full.

 

[blw2]

You've got that right Rene!

You say the exterior is gelcoat.  I assume that, whatever it is, is still intact and looking good on the outside.

I think the "proper" repair is to just replace either that whole wall panel or a portion of it up to a logical seam location.  I had some rot in my rear wall repaired under warranty.  That's what they did.  The exterior color was discontinued so they provided the wall generic white (I think...maybe it's really some other color) then painted it.  Looks like a quality automotive type paint job to me...

That said...If it were me...since painting like that is outside of my skill set..and since I have no idea where I'd even source replacement material to match...
and if the exterior is still intact and looking good
and if I'm right in thinking that it looks like a fairly small area of bad wood...

I think what I would do is to carefully remove all of the bad wood that i possibly could...taking it well into good wood as much as possible
if at all possible I scarf it out in a rectangular shape to do it as a dutchman repair....but I imagine that would be tough to do.... still that's what I would aim for.
Then I'd soak it thoroughly with this stuff
https://www.rotdoctor.com/
then I'd carefully glue in some lamination layers of plywood to really strengthen that wall so it's solid again (or I might teach myself fiberglass layup for what I assume might be an even better repair)

some of that spray in foam insulation like they put in houses would prob help stiffen it up too... something else I'd think about but prob not end up doing.

 

[regval]

Most inside wall panels on a framed RV trailer are available from parts sources. They are 4ftx8.5ft The 5th wheel wall construction on your unit uses metal (some are aluminum, some are galvanized studs) and the wall panels are glued to the studs, with fiberglass mat insulation or rigid foam inserts in the stud voids. The panels are thin luan plywood covered with a decorative pattern or solid color.  The outside wall panel is usually Filon, a material made of stranded fiberglass and shipped rolled to fit in a tube, sold by the foot.  The Filon is usually glued to luan plywood panels or sheets, which is then bonded (glued) to the outside of the wall studs. So, what I've seen and done for repair is to remove the damaged inside panels and insulation and replace. Not difficult. The outside is the challenge because sectional repair is usually not acceptable for cosmetic reasons and the whole side, front or rear, is done so that a good "factory" look is maintained. Anyway, construction is construction, finding the materials, time and place to do the work yourself is the make or break decision.

 

[Guest]

If it has not been mentioned or you have not done so yet, get a squirt bottle and put a cap full of bleach in it and fill it with water.  Then lightly mist the area, it should get of any black mold.  It wont remove all the discoloration but it will get rid of the mold.

Also be sure you take an ice pick or some pointed tool and poke around to be sure you got all the rot out. 

I would also drill some small weep holes in the horrizontal braces so that if it ever does leak again, the water will run down and not be trapped there and rot, it will also allow air in so it can dry out.

+1 i totally agree, find the leak and seal it. 

 

[FuelinAround]

I got about 3 more hours logged tonight. Mostly removing the beds and beginning tear out if the rear section. My biggest concern today is the areas where the luan/plywood behind the metal studs. They were glued to the metal studs and now that the wood has deteriorated in some places there is not a strong bond. I had local RV guy look at it today and he seemed to think I would be ok. I personally am worried about fixing the issue correctly and for the long term. Is there anywhere I could take it for repair or would you all agree with the local repair guy. I?m only about 5 hours from Winnebago towable who purchased Sunnybrook.

 

[Guest]

Is that included in your pics, if not please show a sample pic...

Also you know you dont have to do a new post for every pic, under where you add pics there is a button to add additional pics to the same post