Strange waves appearing on the fiberglass surface

[CaTrem]

Hi guys,

We own a Vista Cruiser 23CSK (2017) trailer. The maintenance is up-to-date and the outer silicone seals appear to be in excellent condition.
Recently, strange waves appeared on the fiberglass coating (front side - exterior). See pictures.

To our knowledge, there has never been any water introduction from the outside.
We only experienced 1 or 2 very cold nights 2 years ago, during which, due to a lack of ventilation, the condensation of our breaths made water trickle on the inner walls.

Note also that this side of the trailer is on the sunny side when it is parked in our driveway.

What would be the cause? how can we fix it (do we have to fix it)?

 

[SlimTim]

I believe this is caused when the exterior wall material delaminates from the interior wood backing material. Typically this is caused be water intrusion into the camper. It is happening near the bottom of the wall because that is where the water is travel and it stays damp in that area. In regards to how you fix it I think you have to replace the entire piece. I don’t think there is a way to remove the wood backing and replace with new wood and laminate them back together.


However before fixing you should try and find the water leak. Or at a minimum get to the inside wood backing and see if it’s wet or rotted.

 

[SlimTim]

FRP Plywood sandwich panels.

Look up this on Google and you will get a better idea how the external wall is constructed. Also I suppose the moisture could be i between the sandwich layers and not visible inside the camper.


However you may find how to fix this without replacing the entire piece.

 

[Texas Shriner]

Slim Tim is all over it. That is delamination and likely caused by water intrusion. Find the leak and then repair or replace. I'd think that replacement will be called for as that piece is under stress and it will be difficult to keep it sandwiched tight while injecting a bond.

 

[Dennis4809]

First thing is to fix the leak. Reseal everything from the roof down. This won’t get better and will kill resale but if you can keep from getting worse and can live with what you have, go camping.

 

[CaTrem]

Ok. Thank you all for your comments.

We re-re-checked the roof joints.
Finally, we found that the water came from the parking light (the one on the right in the photo)... This is now repaired.
The left one was ok but we didn't take any chances and resealed it.

Depending on the effort required, we are considering whether we should check for mold and then try re-laminating...
We have no intention of selling the trailer on short-mid term.

To be continued!

 

[SlimTim]

I like to try things so I think I would build a jig or something that allows me to put pressure and hold the delaminated area flat. Without the jig in place I would drill a hole through the wood backing but not through the fiberglass. I would drill the hole from the inside near the highest point of delamination. I would then inject an epoxy mix into the wall so hopefully it runs down into all the delaminated areas. Once the epoxy is injected I would install the jig and then let it cure. They make some liquid wood that flows about like water so it should penetrate into the wood and stabilize it once it cures. Please let us know how it works and what you did if you try and fix it.

 

[CaTrem]

I've just met with my local RV retailer and they told me they do not think it is only a water ingress that could have caused the delamination. Especially if we only suspect a small hole in the upper right parking light seal.
They usually see that high annual temperature variations (like here in Quebec, 90F to -22F) is often the cause.
They offered me to perform a humidity detection test to be sure there are no humidity anymore. And for the repair, they confirmed that it can be VERY expensive since it is a one-piece fiberglass layer.

@SlimTim
Thank you very much for your suggestion, it could work!
I'll keep you informed.

 

[mzweili]

Hi CaTrem, when pushing the bubbles in you hear a crispy noise, that indicates a delamination caused by a bad bonding (manufacturing defect). If the bubble comes out silently, the delamiation was caused by water infiltration. Explanation: the crispy sound is caused by the remaining glue. If there is no sound that indicates that the under-laying wood is wet.