This is a continuation of my first relamination project, found here, that focused on the sidewalls. This project is for the front wall of the trailer. The front wall is completely "delaminated". I put that in quotes because it isn't clear if the front wall was ever laminated at all! Here is what the front wall looked like before starting on this project.



At some points on the front wall there is about 2" of deflection. The entire wall looks a bit lumpy in person. Pictures don't show how lumpy it is.

To start, I want to go through some forensic analysis. It may help others to understand why delamination happens and how to head it off.
1. The molding on the roof where the front wall fiberglass meets the roof EPDM was never fully secure from the factory. In my Bathroom Remodel thread I found that the factory had completely missed putting screws into the roof 2x4 and they were only in the roof substrate (7/16" OSB). Many of the screws that I checked were stripped. That allowed the molding to come loose, allowing water to get under the molding.

2. The butyl tape under the roof molding was inadequate. It was thin and brittle. Once water got under the molding it could easily get past the butyl tape.

3. At the roof molding, the EPDM was layered under the front wall fiberglass. When water got past the molding and the butyl tape it went right under the fiberglass and into the trailer. It seems to me that the fiberglass should be layered under the EPDM. The drawing below shows what I found. The blue line is the roof and wall. The angle is exaggerated slightly but the trailer does slope down to the front like that. The red line is the EPDM and the green line is the fiberglass.


This photo shows the remnants of the front wall fiberglass on top of the EPDM.


4. There was little to no support for the fiberglass where the roof curved into the front wall. In the picture below is a curved block that the fiberglass is supposed to follow.


Normally, fiberglass would have a backing substrate to support it as it went over the curve. Note that the curved block is almost the same height as the OSB roof substrate. That meant that if a Lauan substrate had been used, it would have been higher than the roof. No Lauan was removed from the curve. Instead, what came off of there was what looked like cardboard. Because of the water intrusion, almost all of the cardboard had deteriorated.


This curved block is just about the right height for one or more layers of Lauan. The pink rigid foam was put in place from the inside of the trailer during the bathroom remodel.


5. The cardboard backing was used all the way down to the diamond plate aluminum. There was no adhesive or fasteners used to secure the backing to the studs. In other words, the entire expanse of ~80 square feet of fiberglass was free floating. The only thing holding the fiberglass down is the molding on the four sides. The sidewalls aren't like that, so why would they do that on the front wall?

6. The roof molding (where the EPDM and fiberglass meet) didn't extend far enough to the edge of the roof. Each end was about 2" short of the side. Maybe that's OK, but it seemed strange that the molding wasn't taken to the edge where there was a solid 2x4 that could have been used to hold the molding down.

The Repair Plan
1. Replace the fiberglass. The existing fiberglass is too torn up on the four edges, especially the sides, to reuse it. Plus, cleaning all the backing material off would be a ton of work.
2. Install 1/8" Lauan as a backing substrate to provide rigidity. The Lauan will be glued and stapled to the studs. 1/4" Lauan would provide more strength, but it would put the fiberglass too far out from the studs. The farther out the fiberglass is from the studs, the less area the side molding will cover on the sidewall. The original side molding didn't cover the sidewall in some places. I didn't find this until I removed the caulk along the side molding.
3. Trim the curve blocks down slightly so the 1/8" Lauan gently meets the roof's OSB.
4. The 1/8" Lauan may be too stiff to conform to the curve where the roof meets the front wall. I'll cut the Lauan into 1" to 2" wide strips to create a discrete curve for the fiberglass to follow. I may sand where the Lauan strips meet to smooth the curve.
5. Reinforce any places in the wall where something from the outside is screwed into. Specifically, the ladder mounts, running lights, cargo door latch and the top and bottom molding.
6. Eliminate the shower bay (lower left in the first picture) and the light fixture (next to the show outlet). Both of these items had water intrusion. I don't use either of them.
7. Replace the diamond plate aluminum. There are tears in it and it's very flimsy. The new diamond plate will be a heavier gauge.
8. Re-glue the EPDM down to the OSB. I already have the glue from a prior project.
9. Replace the top and bottom molding. The top molding will be replaced with a larger format trim cap. The bottom molding will be the same size.
10. Replace all the insulation with 1.5" R-7.5 rigid foam insulation. The foam insulation will be glued to the studs.
11. Treat the water damaged areas. I'll use a mold killing primer everywhere and epoxy on the spots that are weak.
12. Use lots of butyl tape!

 

Most, if not all, is from water intrusion and can be linked back to poor roof maintenance. I inspect the Dicor twice a year and can usually find signs of cracking somewhere.

 

Mostly, I agree. In my case, all the lap sealant in the world might not have helped since the molding wasn't staying down.

 

Jim you have a project on your hands for sure. Nothing worse than water intrusion.

 

Following along. Amazing work so far. We do one of these at work at least every month. RV builders cut so many corners!

 

Here's what the front wall looked like with the fiberglass skin removed.


I removed everything down to the studs.


After spraying down the wood with a water/bleach solution and letting it dry I used Zinsser Mold Killing Primer to ensure a good seal on the wood.


I ran PEX line up the wall and through the attic. I put that in place so I can try to run my trailer camera wire through it instead of running the cable outside the front wall and on top of the roof. The unpainted 2x4 boards are all new. I put those in to support the molding where the fiberglass meets the aluminum diamond plate. There was water intrusion at that joint because the molding didn't have enough to bite into to hold it down.



All the old batt insulation was replaced with 1.5" rigid foam insulation with a rating of R-7.5, which was at least twice as much as the prior insulation.


The crown needed some special attention. The new fiberglass needed something with some structural strength underneath it. I used 3/8" Coroplast. I made relief cuts on one side of the sheet so that it could easily form a curve.


With the Coroplast in place, the curve was very rigid.


1/8" Lauan plywood sheets installed using Loctite PL-Max glue and staples. I really despise Lauan plywood. 1/4" would have been easier to work with, but that would have increased the thickness of the wall, which would have some consequences. The Lauan was necessary because the contact adhesive would have melted the foam insulation. I tested that. It would not have been pretty.


The new fiberglass was 8'x10'. We cut it to length, but left it as the original width. Rather than trying to align the fiberglass on two sides, by leaving the fiberglass too wide it allowed us to focus on the horizontal alignment and get that 100% right. The picture below shows much extra fiberglass we had on one side. I used my router with a flush trim bit and a bearing guide (pictured below) to give me a nice, close fit. The 3M 1357 Contact Adhesive did a great job. It was expensive at $143 for a gallon, but if it holds the fiberglass down it will have been worth every penny. I used Weldwood contact adhesive on the diamond plate aluminum and I don't think it worked as well.




The fiberglass at the top, with the EPDM ready to lay over the top of it. The factory installed the EPDM under the fiberglass, which I think was a factor that allowed water intrusion. The thin blue line is the new location for the molding that will hold the EPDM down. The old location is about 1.5" to the left of the line. The factory completely missed the 2x4 that is located under the thin blue line. This allowed the molding to lift up and let water get in.



The almost final product. The molding where the fiberglass overlaps the new diamond plate aluminum wasn't on yet.


The corner molding needed relief cuts to allow it to follow the curve of the crown without kinking. I used 2" butyl tape on the molding. Before installing the molding (with the butyl tape already on it) I installed Dicor Seal-Tite Corner Seal Tape. Should water get past the caulking and then past the butyl tape, the Seal-Tite should keep it from going any further.


The new molding was larger than the old molding. It had a lot more volume under it. I used a buttload of butyl tape. Yes, it was a little too much. I had to wait a couple days for the excess to stop oozing out before I could apply the Dicor Self-Leveling Lap Sealant.

 

A few more pictures, finishing up some of the minor details.

The corners of the diamond plate aluminum skirt were a little goofy so I created plates to cover the corners. In this first picture the vinyl trim in the molding wasn't long enough. I replaced it with new trim to reach the end of the molding.


The cutout of the aluminum diamond plate around the tongue was rather sharp so I put some trim on the edge, which also covers up my lousy cut. It would have been a lot easier to put the trim on BEFORE the diamond plate was installed, but I didn't have the trim at that time.


The bottom 8" of the diamond plate wasn't supported by the wall, so it was a little sloppy. I suspect it flexed a lot on the road. To prevent that I added a bracket on both sides of the tongue. One bracket was enough to firm it up. The bracket is made from old molding.


I used a hole saw to reinstall the SAE connector for my ground deployed solar panels.


Here's how it looks at the end of the day. I think this is the first picture with the ladder back on the wall. The ladder doesn't look straight and I don't think it is an optical illusion. With the solid base that the ladder is screwed into and the use of butyl tape and caulk, I don't think there will be any water intrusion from the ladder.

Still missing are the orange running/clearance lights that were near the top of the wall. I did run the wires for the lights and I'm pretty sure I can find where the wires are behind the fiberglass. However, given the water intrusion risk that those lights present, I'm probably not going to put them back in at all.


Phase III, if I get motivated enough, will be to rebuild the small section of wall above the rear cargo ramp. I think there is a problem there that lack of maintenance on the roof molding allowed water to get in. I already rebuilt a corner of the roof in that area and sealed it. Maybe next year.

 

Love how you did that. Great work! Too bad it wasn't built that way in the first place.

 

Jim..... I am guessing that the two upper clearance lights might be required......??

 

Could be. I'm not planning to put them back on at this time.

 

It would be fairly simple to do if you should decide to.

 

I've thought about it. Finding the exact spot where the wires are will be interesting. I think I can come within 3/4" on my first try.

One option I thought up was to pull the wires from just one side through a gland (to try and prevent water intrusion) and run a 6' orange LED strip light across. That way I have a single point to worry about sealing.

 

Now this is a great idea...and it would look good. Do it. Cmon, do it. LOL

 

I'm kind of burned out. I spent a lot of time on this last project. I'm still sore.

 

Man I hear you. I got there after my last truck project. Haven't really touched it since last year other than small stuff and maintenance.