Delamination: Why it’s important and how to spot it

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By Jon Gaver
Certified RV inspector

When purchasing an RV with a fiberglass wall, one of the most important things to watch for is delamination. But, many RVers wonder what it is, why it is important and how to spot it in an RV they are considering buying.

An RV 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, delamination may spread, as moisture seeps further into the laminated structure.

Identifying Possible Delamination

Delamination appears as wrinkles in the fiberglass. In the photo above, 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 second photo below, 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.

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 results.

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 can be a very good repair method. But caution should be exercised, to ensure that it does not weaken the wall or create potential moisture intrusion issues.

Replace the whole wall.

Unless you have a lot of money to throw at the repair, 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.

Walk away.

Due to the cost of repair and the potential for other problems, it may be best for an 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 facility. You may find it reasonable to move forward. But you could just as easily realize that walking away from the deal may be your best option.

You should always have your prospective RV purchase inspected by an inspector certified by the National RV Inspectors Association. 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, the owner of RV Inspector Pro, is a Level 2 certified RV inspector currently based in Humble, Texas. He has a degree in engineering and experience working with electronics, engines, generators and air conditioning. He can be reached by emailing or by calling 713.253.1723.

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  • Ron Burkett says:

    nice article john, I have a lot to learn. My wife and I are just getting started and expect to purchase a pull behind soon. We are attending the Atlanta RV Show this weekend. Give us one “must know” recommendation. BTW, I was born and raised in Dallas, but currently hail from Chattanooga.
    Ron Burkett

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