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Author Topic: Wall Construction - Dry Rot in Slide Out  (Read 536 times)

Mark Parker

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Wall Construction - Dry Rot in Slide Out
« on: August 06, 2018, 10:11:41 PM »
1999 Beaver Contessa (SMC) Naples 40' with 1 slide.

We are the 3rd owners of our Beaver and we love it.  We have been doing thousands of dollars of upgrades.  In the process of redecorating the slide out today I discovered some dry rot.  Arrgh.

My questions are:
1)  How is the wall constructed?  From the inside I can tell there is a luan panel over extruded foam between vertical steel square beams.  How far up do the square beams go?  Is it a complete frame supporting the top of the slide out?

2)  There are 4 screws at the front edge that go through a piece of metal and into the panel (and presumably what is beyond).  What happens if I remove these screws while repairing the panel?

Observations:
The dry rot does not extend below the window.  I am not 100% sure of the source of the water infiltration, BUT upon close examination of the outside, there is a metal piece of edge trim at the front of the slide out that is held on by pop rivets.  Most of the pop rivets are no longer doing their job and there is some separation occurring.  I suspect this is the entry point.  The other possibility is the awning attachment point at the top front corner, but I don't see anything obvious.  When I sight down the exterior I can detect a slight ripple in the problem area (almost like delamanation)...but is so slight that I had never noticed it before (say 1/64").

Proposed Plan of action:
I want to remove the screws and cut the bad interior panel back to the second (or third) square tube support and replace it with a new one.  Then replace the screws.  I really don't want to have to remove the window and hope that I can slide the new piece under the front and lower frame where required. 

Then put new pop rivets in the exterior leading edge.

It doesn't appear that the rot extends to the small area in the overhead cabinet...I am hoping that I don't have to drop the cabinet too. 

1999 Contessa (2017 -  )

Steve Huber Co-Admin

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Re: Wall Construction - Dry Rot in Slide Out
« Reply #1 on: August 07, 2018, 02:50:15 AM »
Mark,
I'm pretty sure the aluminum struts run to the top of the slide.  The pop rivets and awning attach are both prime candidates for leaks. Consider using Lexel to coat any rivets you don't replace. I'd also put a dab of Lexel on each rivet hole before installing new ones. After you get the panel removed you may want to wet down the outside to see if you can spot the entrance point. Many times it takes wind to blow the water into the gap so don't be surprised if you don't see any, but it's worth a try. I'd make the new panel removable if possible in case you didn't get the leak sealed.
Steve
Steve
2015-          07 Contessa Bayshore C9,  400 hp
2013-2015: 00 Marquis Tourmaline, C12, 425 hp
2005-2013: 01 Contessa Naples, 3126B, 330 hp

Mark Parker

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Re: Wall Construction - Dry Rot in Slide Out
« Reply #2 on: August 07, 2018, 10:57:11 PM »
Thanks Steve.

I started removing the panel.

The square tubing is steel (not aluminum) and the tube nearest the end doesn't run straight up to the top...it only runs up to the tube under the window, BUT there is a tube that runs up the side of the window a few inches away, so the effect is pretty much the same.  There is also a square tube above the window that runs horizontally, so I am not too worried about any support issues while doing the repair.

I still don't know what will happen if I take out the 4 screws (circled in yellow) on the leading edge.

I plan on using 5mm underlayment as a replacement panel glued to the foam.

Is there any material between the foam and the fiberglass exterior wall?  How is the glass bonded to the wall panel?

1999 Contessa (2017 -  )

Steve Huber Co-Admin

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Re: Wall Construction - Dry Rot in Slide Out
« Reply #3 on: August 08, 2018, 02:17:46 AM »
Mark,
I think the fiberglass is bonded with an adhesive of some sort but not sure what it is. Looks to me like the 4 screws are there to anchor the panel to the outer wall. A call to BCS or a body works service provider might give you more insight. You might want to check out the Service Providers list for one in your area. It's in the Private Members Only board.
Steve
Steve
2015-          07 Contessa Bayshore C9,  400 hp
2013-2015: 00 Marquis Tourmaline, C12, 425 hp
2005-2013: 01 Contessa Naples, 3126B, 330 hp

Mark Parker

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Re: Wall Construction - Dry Rot in Slide Out
« Reply #4 on: August 08, 2018, 04:54:40 PM »
thanks again Steve.  Looks like you had virtually the same coach as ours for 8 years.   :)
1999 Contessa (2017 -  )

Steve Huber Co-Admin

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Re: Wall Construction - Dry Rot in Slide Out
« Reply #5 on: August 08, 2018, 10:41:05 PM »
Mark,
Just got reminded that if you coat the new 5mm underlayment with several coats of polyurethane (oil base minwax is good), if water does intrude again it should not cause it to rot anytime soon. (Thx, Ed)!
Steve
Steve
2015-          07 Contessa Bayshore C9,  400 hp
2013-2015: 00 Marquis Tourmaline, C12, 425 hp
2005-2013: 01 Contessa Naples, 3126B, 330 hp
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Mark Parker

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Re: Wall Construction - Dry Rot in Slide Out
« Reply #6 on: August 08, 2018, 11:08:25 PM »
great point.  I wouldn't have thought of that.  I finished getting the old luan panel off the styro, and cut the new 5mm panel to fit.  It is slightly thicker than the luan panel it is replacing, so some bevels, etc were required.  Fortunately the seams will be hidden by the window box, and the sofa (or entertainment center if we swap sides in the future. 

Turns out that the exterior wall is of the same construction....foam inner core then luan panel glued on top, the the fiberglass bonded to the luan panel..Unfortunately that panel has dry rot too.  No clue yet as to what I'll have to do there.

1999 Contessa (2017 -  )

Steve Huber Co-Admin

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Re: Wall Construction - Dry Rot in Slide Out
« Reply #7 on: August 09, 2018, 01:15:30 AM »
Mark,
If you don't see a lot of "waviness" looking at the fiberglass from outside the coach you may want to leave as is. Although I've never dealt with it, it seems that one would need a method of "pressing" the fiberglass to the luan or vice versa to  get a good seal and reduce the waviness/wrinkling in the outer skin.
Steve
Steve
2015-          07 Contessa Bayshore C9,  400 hp
2013-2015: 00 Marquis Tourmaline, C12, 425 hp
2005-2013: 01 Contessa Naples, 3126B, 330 hp

Darell T Hostland

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Re: Wall Construction - Dry Rot in Slide Out
« Reply #8 on: August 09, 2018, 02:08:10 PM »
My wife and I repaired a similar issue on our 1994 Patriot. We clamped 1 inch plywood on the outside against the fiberglass with 2x4's. We removed all the dry rot from the inside and old damaged Luan. We dribbled Gorilla glue down the wall between the fiberglass and the Luan on the fiberglass. Gorilla glue needs moisture to cure so don't worry about the wall being wet between the fiberglass and luan. You can replace the foam insulation and new wall panels on the inside in the same way. The fiberglass outside wall has no bubbles or waves on it and the paint was not damaged it is better then new. Also check the factory caulking at the top of the wall where roof meets the wall. Our rv had about 3 feet above drivers window with no factory caulking and about 2 feet above the door and side window.It turned out so good that we changed all the rug on the walls to new paneling.I posted pictures on a thread that had the same problems as this. Take your time and plan all the steps and have all tools and construction materials needed for the job. It is well worth the effort. It took us about 2 weeks to do all new paneling on both sides in the living area. My wife removed all the old flooring and made a paper template of the floor. She put in new flooring all in 1 piece in the kitchen and living areas as well as on the steps.
Tim/Joyce Hostland
1994 Patriot Savannah 33
2008 Jeep Liberty
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Mark Parker

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Re: Wall Construction - Dry Rot in Slide Out
« Reply #9 on: August 09, 2018, 07:08:43 PM »
great feedback.  Thanks.  I hadn't thought of using the moisture to my advantage (w/ Gorilla Glue).

Reading your posts on the thread: "Beaver Patriot drivers side window leak" made me go to the cockpit and take a close look.  AAAAaaarrrrgggh.  I have dry rot there too.  Sigh.  :o

Once I finish the interior slide out repair and painting, the new Pergo laminate (Sand Dune Oak) goes in.  The next project scheduled after that was a rebuild of the instrument panel/center console.  I guess I'll strip down the wall and do that repair first instead.
1999 Contessa (2017 -  )