Fiberglass Bulge – Bubble

Question: I have a 2008 Prowler trailer with a slight fiberglass bulge in the side. There doesn’t appear to be any water damage and it’s a local trailer that had no exposure to extreme weather. It almost looks like a “de-lamination” from the plywood. Does that make sense? Is this an issue or can it be repaired or should I concern myself with it?

Answer: Based on what we know, it could be de-lamination or something called intrusion.

If it is de-lamination, then the cause is the failure of the bonding agent to the substrate (plywood). This problem can be caused by water/moisture between the layers or by a failure during the manufacture of the RV.

If it is water or moisture intrusion then you must address this problem ASAP. However, if the problem is caused by a manufacturing defect then it may only be cosmetic and as long as it does not spread, we would leave it alone. We strongly recommend that you seek help from an RV repair facility that you trust to diagnose the root cause. De-lamination is fixable but it can be a costly repair and is not a DIY job unless you are experienced in this field.

If the problem is intrusion then nothing needs to be done. Several spots around our RV have bulges caused by intrusion. BTW, intrusion is when under laying frame of the RV bulges out and causes the fiberglass on the exterior of the RV to bulge.

You can tell the difference between intrusion and de-lamination by pushing hard on the bulge with the palm of your hand. If it does not give, then you have intrusion.