Delamination – What It Is, How To Spot It, And Why It’s Important

(This article was originally written for and published in RV Daily Report on January 13, 2019.)

When purchasing an RV with a fiberglass wall, one of the most important things to watch for is delamination.

What is Delamination?

A fiberglass wall is a thin, flexible piece of fiberglass, laminated to a thicker, rigid substrate. The resulting wall should be stronger than either material.

Lamination isn’t just gluing two substances together. A vacuum is drawn on the whole wall, for the duration of the curing process, forcing the two materials together. A day or two later, the vacuum is released and the wall is a solid structure.

Delamination is what happens, when glue between the fiberglass and the substrate fails. Such failure is most often the result of moisture intrusion. Furthermore, once begun, delaminationmay spread, as moisture seeps further into the laminated structure.

Identifying Possible Delamination

Delamination appears as wrinkles in the fiberglass. In the above photo, you can see some of those wrinkles. But at that angle, the wrinkles might be mistaken for reflections. So rather than look straight on at the sidewall, look down the side, at about 10 to 30 degrees from parallel with the sidewall.

When viewed from this angle, the same delamination seen in the below photo, becomes very apparent.

Aside from cosmetic issues, delamination can weaken the wall structure. Also, moisture inside the wall can eventually lead to mold.

Dealing With Delamination

There are three ways for an RV buyer to deal with delamination.

  1. Cut out and replace the damaged wall section.
  2. Replace the whole wall.
  3. Walk away.

Let’s look at each of these options.

  1    Cut out and replace the damaged wall section.

By far, the most inexpensive repair method is to cut out and replace the damaged wall section. It’s also likely to be the most common type of delamination repair. However, this method creates two other possible issues – both related to the new seam that you end up with.

First, although modern fiberglass repair methods can create very secure seams, it is seams where you’re most likely to find moisture intrusion.

Second, the structural integrity of the wall may be weakened. A single-piece wall will generally be stronger than a wall with a seam. But depending on the location of the repair and the size of the replaced section, the seam may not weaken the structural integrity of the wall.

Cut out and replace canbe a very good repair method. But caution should be exercised, to insure that it does not weaken the wall or create potential moisture intrusion issues.

 2    Replace the whole wall.

Unless you have a lot of money to throw at it and have an extremely good reason to do so, this is probably not a very good option. You can get back to a single-piece wall – but at a price that is not generally cost effective. For this reason, it’s an option that most people will avoid.

 3    Walk away.

Due to the cost of repair and the potential for other problems, it may be best for the RV buyer to just walk away from the deal. But that’s a decision you have to make for yourself. Depending on the amount and location of the delamination, repair may be a viable option. Work with the seller. He may be willing to absorb some or all of the cost. Evaluate the cost, along with the potential for future moisture intrusion or structural issues. Talk to more than one RV repair service. You may find it reasonable to move forward. But you could just as easily find that walking away from the deal may be your best option.

You should always have your prospective RV purchase inspected by an NRVIA Certified RV Inspector. But there is no reason why you shouldn’t do some inspecting of your own, before you call the inspector. Your own preliminary inspection could save you the cost of a professional inspection, should you happen to find a show-stopper issue. But a professional inspection goes much deeper and has the potential to save you thousands of dollars in repairs. On the other hand, it might just give you a sense of security about the coach you are about to buy.

For the record, the client for the coach pictured in this article walked away from the deal, in large part, because of this issue.

John Gaver is the owner of RV Inspector Pro, based in Houston, Texas. He is an NRVIA Certified Level 2 RV Inspector. RV Inspector Pro inspects all sizes and types of RV’s, but specializes in Class A and Class C motorcoaches. For more information or reprint permission, John can be reached at our Contact page, by phone, at 713-253-1723, or by email, at

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