[Jack Houpe]

Rick ours had a piece of 3/4" with a piece of 5/8" on top on the front slide, can't tell you much about the rest of the coach.

[Wanderman]

Thanks Jack... sure looks like only 1 layer of OSB and it looks really thin. Almost like it fits into the slots front and rear on the steel frame.

[Tony Van Helden]

Another point to check for soft spots is along the exterior wall under the window and rowards the storage bay. It may even run along the insulation near the engine. Push into the wallpaper.

[Wanderman]

More info. It definately appears that the water ingress is from outside the coach. Likely the seam between the rear cap and the body as well as the weatherstripping that was not attached at the top of the horizontal engine bay access door.

The rotten wood was almost a perfect diagonal line from front right of the bay door to the back left of the engine bay ceiling. I initially thought it was limited to the bottom of the wood/foam/wood sandwich, but it was both top and bottom, with some on the inner body wood (no idea why that's actually glued there???)

After removal I ran the tub/shower and toilet a lot and there is no leaking water from there at all.

I was told by Newell that the wood was marine plywood 1/2" each piece with 1" foam board in the center. You can see by the pictures this is not the case as it's obviously OSB. It sits on a squared "C" channel all the way around with vertical pieces of plywood shaped into a box to support the tub and tub surround above. It appears that it was assembled before the floor above was laid down. I am hoping I can finagle the new pieces in there somehow. I still have to get some of the non-rotted wood out of the back slot, as it's in there tightly with some adhesive on the vinyl fabric making it very tight.

I will be using a water resistant 1/2" actual plywood and will probably put some non-flammable paint on the outer two sides (top and bottom) as the foam board is glued to the inner faces. I'll use some additional paralastic adhesive to stick the vertical tub support box pieces above to the tub bottom. And then some expanding foam to fill the voids around. Lots of those, likely for where the jacuzzi machinery would have been if my coach had that option.

Then the rest of the layers are attached to the underside plywood with an aluminum angle frame and screwed to both the underside of the steel "C" as well as long wood screws and fender washers at various places to hold the diamond stick cloth blanket in place.

[Wanderman]

I HIGHLY suggest everyone checks their engine bay ceilings!If the fabric diamond stitched cover hadn't fallen down, I would never had seen the extent of the water damage. If untreated, it very well could have propagated to the other side of the tub/shower as well as the main floor (granite) of the rear bathroom. Thankfully, it appears I caught it in time.

I am replacing using a much better quality of plywood with superior water resistance. The OSB that newell used really isn't the right type for this area. They told me it was marine plywood... it clearly wasn't. I wonder what else isn't?

In the photos, you can clearly see the "ledge" that this roughly square plywood/foam/plywood sits on. It was put in from the top, them the other pieces were nailed to it, again, from the top. As long as I can slide the new sandwich in there and secureit properly, it should be fine. Removing the bathroom flooring and tub is not something I'd like to do....ever!

[Richard]

One thing to check for is the shower insert for shampoo holder. When I redid the shower, I found water had been seeping around that insert for a very long time.