Delamination

[Mcleoddude]

I hate my first post on a forum being one asking for help or suggestions but im in need. So this is my first travel trailer. Its a 2019 Keystone Bullet 243bhswe. I had it parked in outdoor storage without a cover on it since i bought it. I check it weekly....atleast try to. Well, anyway last week i noticed what seems to be delamination of the rear panel. I can push the laminate in a few inches like its bowing outward. I popped the lower window out to see the extent of the damage and saw no evidence of water intrusion. My big question is i cant feel or see old epoxy residue on the aluminum studs? The exterior looks like a thin coating of laminate bonded to fiberglass? Am i good to just use the method some people use on youtube and squirt epoxy in there and reseal it up? What is the construction material Keystone used on the exterior wall? I ordered Wet Systems 105 epoxy already thinking it work. If there is a better method please let me know. Thank you for any and all help with this.

[gkainz]

I’m far from an expert, but what I’ve read is generally, Keystone free hangs or floats the rear wall … what looks like delam is “normal” on the back wall.

[JRTJH]

Yep, for the most part, it's normal. That said, when you broke the sealant bead by removing the window to check things, you may have created a leak, so watch your window carefully !!!!!

Keystone uses a "floating rear wall" in nearly all their trailers. It is a 1/8" thick FILON (fiberglass sheet) backed with either luan (Asian plywood) or pressboard (thick cardboard) as a backer. The only places where the rear wall is attached to the aluminum studs is where there are "wall penetrations". Those are usually the molding strips along the top, bottom and sides of the panel, the windows, clearance lights, tail/stop light fixtures and maybe a grill rack, license plate mounting plate or such...

The rest of the rear wall "just hangs there, taking up space"... Sometimes it may slip out from under the top molding (along the roof/rear wall joint) and billow. It may also slip out of the side moldings and buckle vertically. You can inspect both of those by looking for sealant stains as evidence of the FILON moving out from under the molding.

In the summer, the sun's heat will cause the FILON to get hot and expand. When it does, the result will be "loose appearing bulges" between all those "through the wall penetrations" that are "screwed to the aluminum studs....

So, what you're seeing is not delamination, but rather gravity pulling on the FILON sheeting. That said, pay close attention to the window you reinstalled to make sure you didn't "create a leak" .....

What you're seeing is "normal hanging rear wall appearance"...

[chuckster57]

On a trailer that old we would have replaced the window seal, not worth the risk.

[JRTJH]

Also, you mentioned using an epoxy adhesive to "reattach the FILON to the aluminum studs... I'd advise NOT to do that... If you do glue the FILON to the studs, then the rear wall will no longer hang on the rear of the trailer as you tow. but will be rigid and buckle and flex as the aluminum superstructure twists with the road during towing. That may crack the FILON rather than allow it to just "hang there".

While many/most of us wonder about what Keystone was thinking at times when we see the way they build these things, it's pretty safe to say that the engineers at the factory have worked out most of the kinks in building them and many of our "owner inspired improvements" are things the factory has already discovered are not the "best way to do things".... Gluing the rear wall onto the frame is one of those "leave it alone" processes.....

[Mcleoddude]

Thanks for the help with this. As soon as i saw this it was straight to def con 1. My wife says i got "chicken little" syndrome. The rear seal on the window was a only a foam gasket. Not sure if thats all i should use to reseal it with or not. If anyone has recommendations id appreciate it.

Since i have the indoor storage unit till the 11th im going to reseal everything on the trailer thats starting to look aged. I got new slide seal material from a company called Trim-lok thats a d seal and slide seal combo and got 12 tubes of dicor for the roof. Everything else iv read says the prefered caulk to use is geocell.

[chuckster57]

We use this:

https://www.homedepot.com/p/Frost-Ki...534H/202262324

Seam at bottom in the center, and yes GeoSeal is a good choice.

[Mcleoddude]

I have a silly question. Im going to replace the vinyl trim insert on both sides of the front cap. The trim piece is 1" flattened out and the inside track grooves it fits in are 7/8". When looking for a new insert am i to measure the groove width it slides into or the opening of the track? Thank you.

[chuckster57]

Get the 1”. We use Vinyl insert as it lasts longer.

https://www.amazon.com/RV-Designer-E...41032151&psc=1

[sourdough]

Originally Posted by Mcleoddude

I have a silly question. Im going to replace the vinyl trim insert on both sides of the front cap. The trim piece is 1" flattened out and the inside track grooves it fits in are 7/8". When looking for a new insert am i to measure the groove width it slides into or the opening of the track? Thank you.

As Chuck said, get the 1". Also get the premium or heavy duty insert. The plastic stuff from the factory is junk. Amazon sells it by the 100' roll. Search for rv vinyl trim insert (or something like that). The warmer the day the easier it is to install to me. Chuck has some tips as well I'm sure.

[Dacheedah]

It’s a hung wall. The outer wall is filon laminated to mdf or panneling. It is not bonded, the thin layer of fiberglass is glued in to the wall. The paneling has a light bead of glue to the aluminum studs and the window sandwiches the wall and adds strength. The window either has a seal on it or needs butyl tape as a primary seal , seam at the bottom, and screwed back in. Once secured any butyl pushed out cleaned up and a non sag lap sealant.

[fjr vfr]

The main reason for the rear wall being hung is because most of the cabling, electric, coaxial, etc. is run up inside. The side walls are pre-fab making the rear the prime location for this. Although some come up inside of interior walls.