8/12/25

Is Your RV Siding Delaminating? Here’s How to Spot It & What to Do Next

Hey there, fellow road warriors. Let's talk about something that can make any RV owner's heart sink a little: delamination. You’re washing your rig after a fantastic trip, and you spot it – a bubble on the sidewall. Or maybe it's a weird ripple that wasn't there before. It’s one of those things that seems to pop up out of nowhere & can cause a whole lot of panic.
Honestly, it’s a super common issue, especially with older rigs or ones that have seen their fair share of adventures. But don't despair! Understanding what you're dealing with is the first step to getting it under control. We're going to dive deep into the world of RV delamination – what it is, why it happens, how to spot it, & most importantly, what you can do about it. This isn't just a surface-level problem; it can point to bigger issues, but with the right knowledge, you can tackle it head-on.

So, What Exactly IS RV Delamination?

Let’s get down to the nitty-gritty. At its core, RV delamination is the separation of the layers that make up your RV's walls. Think of your RV wall as a sandwich. On the outside, you have a layer of fiberglass or Filon, which is the hard, shiny surface you see. In the middle, there's a core, which is usually made of a lightweight plywood called luan, & some styrofoam insulation. On the very inside is your interior wall panel. All these layers are bonded together with a powerful adhesive, often using a high-pressure process at the factory.
Delamination is what happens when that bond fails. The outer fiberglass layer starts to pull away from the luan substrate, creating an air pocket. This is what causes those tell-tale bubbles, waves, or blisters on your RV’s exterior. It’s not just a cosmetic issue, though. If left untreated, it can compromise the structural integrity of your rig & lead to some pretty serious damage down the line.

The Main Culprit: Why Does Delamination Happen?

Nine times out of ten, the root cause of delamination is one thing: water. Water is the absolute arch-nemesis of your RV’s construction. It finds its way into the wall cavity, & that’s when the trouble starts. The luan plywood is like a sponge, & when it gets wet, the adhesives that hold everything together break down & dissolve. Once that glue fails, the layers separate, & you've got delamination.
So where does this pesky water come from? Here are the most common entry points:
  • Failed Sealants: This is the big one. The sealants around your windows, doors, roof vents, corner moldings, & any other opening on your RV have a limited lifespan. Over time, the sun’s UV rays, temperature fluctuations, & general wear & tear cause them to dry out, crack, & pull away. This creates tiny gaps where water can seep in every time it rains or you wash your RV.
  • Roof Damage: A leak in your RV roof is a direct route for water to get into the walls. A torn EPDM or TPO membrane, a cracked skylight, or a poorly sealed vent can let water in, which then travels down the wall cavity, causing delamination from the top down.
  • Stress Cracks: Tiny cracks can form in the fiberglass itself over time, especially around areas of high stress like the corners of slide-outs or windows. These might seem insignificant, but they’re an open invitation for moisture.
  • Physical Damage: An impact from a tree branch or a minor scrape in a tight spot can puncture the fiberglass, creating a pathway for water to get in & start the delamination process from the inside out.
  • Manufacturing Defects: While less common, sometimes the issue can stem from the factory. An improper bonding process or a bad batch of glue can lead to premature failure of the adhesive.
It's also worth noting that extreme temperature changes can play a role. The constant expansion & contraction of the different materials in the wall can weaken the adhesive bonds over time, making them more susceptible to failure, especially if moisture is present.

Are You Dealing With Delamination? The Telltale Signs

Okay, so how do you know for sure if you have a delamination problem? It can start small & be hard to spot, but here are the key things to look for. Get in the habit of regularly inspecting your rig, especially after a trip or a heavy rainstorm.
  • Visible Bubbles or Blisters: This is the most classic sign. You'll see raised, bubble-like areas on the fiberglass siding. They can be small, like a little blister, or quite large, like a big wave in the panel.
  • Warped or Bulging Panels: The side of your RV should be smooth & flat. If you notice a panel looks warped, wavy, or is bulging outwards, that's a major red flag. Look down the side of your RV at an angle; this can make waves & ripples more apparent.
  • Soft Spots: Gently press on the exterior walls of your RV. They should feel firm & solid. If you find an area that feels soft, spongy, or gives way under your fingers, that indicates the layers have separated & there might be water-damaged wood underneath.
  • Cracks or Splits: Look for any cracks, even hairline ones, in the fiberglass surface, especially around seams, corners, & joints.
  • Hollow Sound: Tap on the sidewall with your knuckles. A solid, bonded area will have a dull thud. A delaminated area will have a distinctly hollow or drum-like sound, indicating an air gap behind the fiberglass.
  • Interior Signs: Sometimes the problem shows up on the inside first. Look for any water stains, discoloration, or rippling/puckering on the interior wallpaper. A musty smell inside can also be a sign of hidden water damage & potential mold growth, which is a serious health concern.

Siding Types & Their Delamination Risks

Not all RVs are built the same, & the type of siding you have plays a big role in whether you'll face delamination.
Fiberglass Siding (Filon): The Most Common & Susceptible The vast majority of modern RVs use fiberglass siding, often called Filon. It’s popular because it’s lightweight & has a smooth, sleek look. However, this is the type of siding that is prone to delamination. The way the fiberglass walls are constructed can also affect their durability. There are a few different methods manufacturers use:
  1. Hung Fiberglass: This is often found on more budget-friendly models. In this method, the fiberglass sheets are essentially glued to the studs of a wood frame. This is the least expensive way to build the wall, but it also has the highest risk of delamination because the bond is not as comprehensive.
  2. Pinch Rolled Walls: A step up from hung fiberglass, this method involves running the entire wall assembly through high-pressure rollers to bond the layers together. This creates a stronger, more consistent bond than just gluing to the studs.
  3. Vacuum-Bonded Walls: This is generally considered the highest quality (and most expensive) method. The wall layers are placed in a giant vacuum press, which uses atmospheric pressure to clamp them together with incredible force while the adhesive cures. This creates the strongest & most durable bond, making it less prone to delamination.
Aluminum Siding: No Delamination, But Still at Risk You’ll often see corrugated aluminum siding on older or more entry-level travel trailers. The big advantage here is that aluminum siding will NOT delaminate. Since it's a single sheet of metal, there are no layers to separate. However, that doesn't mean it's immune to water damage. Water can still get in through failed seals & rot the underlying wood framing & interior wall panels. The good news is that repairing a single damaged aluminum panel is often easier & cheaper than dealing with a large section of delaminated fiberglass.

The Big Question: Can I Fix It Myself? A DIY Guide

So you've found a bubble. Your first thought might be to call a professional. And in some severe cases, that's the right move. But for many small to moderate delamination issues, a DIY repair is absolutely doable. It takes patience & the right materials, but it can save you a TON of money.
Before you even think about injecting glue, you have to do the MOST important step: find & fix the leak. If you don't stop the water from getting in, your repair will fail, & the problem will just come back. Inspect every single seal, seam, & opening in the vicinity of the damage. If you see any cracked or peeling sealant, remove it completely & apply fresh, high-quality RV lap sealant.
Once you're 100% sure the leak is fixed & the area inside the wall is completely dry (this can take days or even weeks of letting it air out), you can proceed with the repair.
Step 1: Planning & Prep This is not a project to rush. You'll need a good stretch of warm, dry days to get it done right.
  • Gather Your Tools & Materials: You'll need a specialized RV delamination repair kit or the individual components. This typically includes a two-part, low-viscosity epoxy resin, large syringes for injecting, & flexible tubing. You'll also need lots of clamps, scrap wood for bracing, plastic sheeting, painter's tape, a drill, & safety gear like gloves & eye protection.
  • Mark the Area: Use painter's tape to outline the exact area of delamination. This helps you visualize the scope of the project.
  • Protect Your Rig: Cover the area below your repair with plastic sheeting. Epoxy is messy, & you don't want it dripping all over your RV's paint & graphics.
Step 2: Gaining Access & Injecting the Epoxy You need to get the epoxy behind the fiberglass. Sometimes you can do this by removing a nearby window, light, or trim piece to access the gap. If not, you may need to drill small, discreet holes at the top of the delaminated area to insert the tubing.
  • Mix the Epoxy: Mix only small batches of epoxy at a time, following the manufacturer's ratio instructions precisely. Many epoxies have a working time of only 40-60 minutes, so you need to work efficiently.
  • Load the Injector: Suck the mixed epoxy up into your syringe.
  • Inject: Carefully insert the tubing into the wall cavity & inject the epoxy. Start at the top & let gravity help you. As you inject, slowly pull the tube out to spread the resin evenly.
Step 3: Clamping & Curing This is arguably the most critical part of the process. You need to apply even, firm pressure to the entire repaired area while the epoxy cures.
  • Spread the Epoxy: Immediately after injecting, use your hands or a roller to press on the outside of the fiberglass. This spreads the epoxy into a thin, even layer & ensures it makes good contact with both surfaces.
  • Build Your Bracing System: This is where you might need to get creative. The goal is to distribute the clamping pressure evenly. Use large, flat pieces of plywood on the outside of the repair area. You can use a variety of clamps – C-clamps, bar clamps, or even ratcheting spreader clamps that can push against a wall or another solid object to apply pressure to the RV sidewall.
  • Wait: Let the clamps do their work for at least 24 hours, or whatever the epoxy manufacturer recommends. Patience is key here. Removing the clamps too early will ruin the repair.
Step 4: Finishing Touches Once the epoxy is fully cured, you can remove the clamps & bracing. Reinstall any windows, trim, or fixtures you removed. If you drilled holes, seal them up with a color-matched sealant.

DIY vs. Professional Repair: The Cost Breakdown

So, what’s this all going to cost? The difference between doing it yourself & hiring a pro is significant.
Professional Repair Costs Hiring an RV repair shop will be expensive, primarily due to the labor involved. It's a time-consuming process. While prices vary wildly depending on the extent of the damage & local labor rates, you can expect to pay anywhere from $100 to $300 per hour for labor. A small to medium repair, like a 6x7 foot section, could easily cost $1,500 to $2,000 or more. For extensive delamination that requires a full wall replacement, you could be looking at a bill of $10,000 or even more, which often exceeds the value of an older RV.
DIY Repair Costs If you go the DIY route, your main cost is materials. Here’s a rough breakdown of what you might spend:
  • RV Delamination Repair Kit: Kits like those from Composet or other brands can range from $100 to $300. These are great because they come with the specially formulated epoxy & the necessary tools like syringes & tubing.
  • Epoxy Resin: If you buy it separately, a 1.5-gallon kit of low-viscosity epoxy can cost between $90 & $150.
  • Clamps: This can be a hidden cost. You'll need several, & good quality clamps aren't cheap. You might spend anywhere from $50 to $200 on an assortment of clamps if you don't already own them.
  • Miscellaneous Supplies: Factor in another $30 - $50 for things like plastic sheeting, painter's tape, gloves, mixing cups, & sealant.
All in, a DIY repair could cost you anywhere from $200 to $500. The savings are undeniable, but it's a trade-off. You're trading money for your time, effort, & the risk of making a mistake. For many, though, the satisfaction of fixing it yourself (& the thousands saved) is well worth it.

Prevention is the Best Medicine: How to Stop Delamination Before It Starts

The absolute best way to deal with delamination is to never let it happen in the first place. A little proactive maintenance goes a LONG way.
  • Inspect Your Seals Religiously: This is the number one preventative measure. At least twice a year (beginning & end of camping season) & after any long trip, get up on a ladder & carefully inspect every single seam on your RV. Look at the roof, around the windows, doors, vents, marker lights, & corner trim.
  • Reseal Proactively: Don't wait until you see a crack. If a sealant looks like it’s getting old, dry, or shrinking, it’s time to replace it. Use a high-quality RV-specific lap sealant like Dicor.
  • Wash & Wax: Regularly washing your RV removes dirt & grime that can degrade sealants. A good coat of wax provides a layer of protection against UV rays, which helps extend the life of your siding & sealants.
  • Control Interior Humidity: High humidity inside your RV can lead to condensation, which can seep into the walls. Use a dehumidifier, especially during storage or in humid climates, & always use the bathroom fan when showering.
  • Proper Storage: This is a HUGE one. Leaving your RV exposed to the elements year-round is tough on it. The sun beats down on the roof, rain & snow assault the seals, & temperature swings put stress on everything. Storing your RV under a cover or in a protected space can dramatically extend its life & prevent water intrusion. This is where a service like Prked can be a lifesaver. If you don't have space at home, you can use Prked to find a safe, covered spot in a neighbor's driveway or even a large garage. It's an affordable way to protect your investment from the sun & rain that cause so many of these issues. Plus, keeping it stored properly during the off-season means you’re not just preventing delamination, you're also protecting your tires, roof, & paint job. For those with unused space, it's also a great way to earn some passive income by renting out your driveway or garage to a fellow RVer through Prked, creating a win-win for everyone in the community.
So there you have it. Delamination might look scary, but it’s a manageable problem. By understanding what causes it, keeping a close eye on your rig for any early warning signs, & staying on top of your maintenance, you can keep your RV's siding smooth, solid, & secure for many years of happy camping.
Hope this was helpful! Let me know if you have any questions or your own delamination battle stories in the comments.
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