Slide out underbelly material. What is it, 1/2" thick?

Question

I have a leak in my slide-out storage compartment.

I believe the leak is due to the vertical joint on the edge of the slide-out and the horizontal joint on the bottom of the slide-out. The horizontal joint also has a trim piece. The trim piece is flat with a small lip at the bottom. Why it doesn't have a longer lip to wrap UNDER the belly is beyond me. I guess because of the need for the slide to retract doesn't allow them to put in a proper drip cap to throw water away from the underbelly.

In trying to inspect the problem, I noticed the bottom/belly of the slide-out has a weird material on it. It's not the waterproof plastic sheeting thats the underbelly on the rest of the trailer. Its almost like a black 1/2" thick material. Whatever it is, it absorbs water. So when water runs down the side of the slideout, it travels underneath and this material wicks water to the OSB and the carpet that is in the storage compartment. I assume the OSB and the carpet are sitting on this weird material.

Looking in the storage compartment, there is the following layers, in this order.

1/8" luan plywood, 5/8" OSB, carpet and then something under the carpet. I did not yet tear out the carpet. I started by removing the 1/8" luan type plywood and the wet OSB but stopped there. The damaged section is about 12" x 12".

I know what the problem is and am formulating a game plan, but does anyone know what the 1/2" (guessing on thickness) underbelly material is?

The edge is exposed (the trim piece does not cover it) and it easily wicks moisture to the other layers. When I pressed on it, it was like a wet sponge. My quick temporary fix was to try and coat the edge with some of that lap sealant caulk to seal the edge. I know thats not going to work, but I could not stay at the camp to figure out the proper fix.

I also resealed the vertical seam on the outside edge of the slide out.

This post is exactly what mine looks like and also has the same design/water intrusion problems. However my underbelly is not that Darco sheet.

https://www.rv.net/forum/index.cfm/fuseaction/thread/tid/23443150

Thanks,
iso

lancerkeys · Answer

I just replace a section of my slide for the exact reason you stated. Mine had 3/4” plywood covered in that plastic wrap like in the link you posted, above that was a layer of insulating foil backed material and then the carpet over that.
This is what I did:
Cut out bad squared off
Cut new piece to fit.
Coat new piece in water seal paint
Coat cut edge of existing flooring with water seal
Wrap new piece in that plastic stuff
Wrap edge of existing floor with that plastic stuff
Put new piece in (two people would have been helpful)
Attach two pieces together using metal straps and screws
Cover the seam where the two pieces butt together with the black plastic stuff
Put insulating layer and carpet back
Clean up
Admire your work and think of just how much money you saved doing it yourself.

It took me 8-10 hours to do mine, I split it in two days to let the water sealer dry.

isonychia · Answer

Thanks for the help.I am starting to think the material underneath is OSB but it simply looks black from the darco or something.I also learned how bringing the slide in and out wears away at the protective coating/material and thus exposes the OSB, then causing it to get wet.Apparently there are "skis" sold to wrap the edges of the slide made out of plastic. I guess it acts as a wear layer for the friction of the slide going in and  out and also acts as a drip cap in way creating a 4" or so barrier underneath for the water to drip off.I guess there is no way for the manufacturer to install a flexible drip cap that compresses when the slide is brought in.Or maybe, as in my other post, they can make the bottom some type of plastic sheet instead of the **** OSB!!!Idiots.Thanks,iso

grandpakip · Answer

The bottom of the slide in our camper is black painted OSB. The exposed edge was also painted. I just covered it with Eternabond, wrapping it around the side and bottom.
I would think that there should be no rubbing between the slide and the camper. Our slide sits on rollers and is a cable slide. Nothing rubs. Regardless of the type, something is wrong if it rubs the finish off.

isonychia · Answer

GrandpaKip wrote:The bottom of the slide in our camper is black painted OSB. The exposed edge was also painted. I just covered it with Eternabond, wrapping it around the side and bottom.I would think that there should be no rubbing between the slide and the camper. Our slide sits on rollers and is a cable slide. Nothing rubs. Regardless of the type, something is wrong if it rubs the finish off.Thanks for the info.I looked at my bottom panel of the slide out again and it definitely isn't wrapped in that Tyvek wrap stuff. I checked some other trailers and they do have the black material wrapped on the bottom and over the edge.I don't really know what mine is made of and I have no idea why the edges are exposed. It would be nice to know what it is and why the edges are exposed??I wanted to remove the trim piece, then wrap the corner of the slide with the eternabond, then place the trim piece over the top edge and add the sealant. But I don't know yet if my slide is the type that the edge rubs when it is retracted. I will have to look when I retract it and see if I can tell.Better yet, it would be great if I could add a piece of L flashing or even a true aluminum drip cap but I don't know if the 1/4" lip (drip edge) would clear when retracted.My slide mechanism has 2 large bars with teeth. I'm not sure if thats enough to tell what kind of slide mechanism I have. I am not at the trailer to identify it further.iso

huntindog · Answer

isonychia wrote:GrandpaKip wrote:The bottom of the slide in our camper is black painted OSB. The exposed edge was also painted. I just covered it with Eternabond, wrapping it around the side and bottom.I would think that there should be no rubbing between the slide and the camper. Our slide sits on rollers and is a cable slide. Nothing rubs. Regardless of the type, something is wrong if it rubs the finish off.Thanks for the info.I looked at my bottom panel of the slide out again and it definitely isn't wrapped in that Tyvek wrap stuff. I checked some other trailers and they do have the black material wrapped on the bottom and over the edge.I don't really know what mine is made of and I have no idea why the edges are exposed. It would be nice to know what it is and why the edges are exposed??I wanted to remove the trim piece, then wrap the corner of the slide with the eternabond, then place the trim piece over the top edge and add the sealant. But I don't know yet if my slide is the type that the edge rubs when it is retracted. I will have to look when I retract it and see if I can tell.Better yet, it would be great if I could add a piece of L flashing or even a true aluminum drip cap but I don't know if the 1/4" lip (drip edge) would clear when retracted.My slide mechanism has 2 large bars with teeth. I'm not sure if thats enough to tell what kind of slide mechanism I have. I am not at the trailer to identify it further.isoThe edge may not have been exposed when it was new. On some I have seen, the edge exposure occurs when water finds its way into the wood, which then swells exposing the edge. which then is more readily attacked by the next water that finds it..When it is new, there is sealant and a flush fit at that joint. Over time, the sealant degrades and the death spiral starts.

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Slide out underbelly material. What is it, 1/2" thick?

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