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How to Repair RV Fiberglass Exterior Damage

How to Repair RV Fiberglass Exterior Damage

“Crunch” is one noise you don’t want to hear when moving an RV, especially if it’s fiberglass. You can do serious damage in the blink of an eye if you back your RV into something or if something falls onto it. If you experience this situation, learning how to repair RV fiberglass exterior damage is one skill you may need to acquire quickly. 

So what does it take to repair your RV and get it back to looking as good as new? Let’s dive in.

Why Are RVs Made Out of Fiberglass?

Manufacturers use fiberglass when making RVs for a handful of reasons. While fiberglass isn’t indestructible, it’s incredibly durable for how lightweight it is. Unlike metal, fiberglass won’t dent as easily if hit by something. Fiberglass also stands up to the elements extremely well, which is the main reason it’s used for RVs. In addition, fiberglass offers some insulation compared to many other materials and helps control the climate.

Another reason RVs have fiberglass is that you can easily clean them. The slick surface makes it difficult for dirt and road grime to stick to the rig. If washed and maintained regularly, these rigs can look as good as new for years to come.

Some RVs are entirely made of fiberglass, but most RVs have at least the front and rear caps made out of it. Many times the side walls of the RV are made of a fiberglass-like material called filon of a fiberglass sheet. This this is much thinner than a solid fiberglass piece these sheets offer similar benefits.

Fiberglass RV parked next to canyon
If you know how to repair RV fiberglass exterior damage, your camper should remain in great condition and last for years.

Is Fiberglass Durable?

Fiberglass is one of the most durable materials manufacturers use to create RVs. Fiberglass can easily last 20 years or more if maintained properly. However, keeping water from penetrating any of the layers is essential.

If water can penetrate the fiberglass, delamination can occur. This happens when a layer of fiberglass begins to pull away from the backing material. If left unaddressed, the panel will continue to separate, and the damaged area will expand. As delamination occurs, the fiberglass becomes weak and loses its durability. Thus, regular maintenance is the key to keeping fiberglass as durable as possible. 

Check the seals and address any potential issues as quickly as possible. The longer you put off maintenance, the more chances you could decrease the durability of your RV.

Pro Tip: Use our guide on How to Stop and Fix Delamination on Your RV to make the repair process painless.

fiberglass rear cap of rv
Most Front And Rear Caps of RVs are made of fiberglass

Can RV Fiberglass Be Repaired?

While it is possible to repair many of the damages to fiberglass, it’s not always very easy. Fiberglass is a combination of glass fibers and a bonding polymer. To work with it you will need some practice, as jumping in without experience will not yield good results or be very strong.

If your repair is not structural in nature, you might be able to make the repair with a filling material like Bondo instead. These fillers are much easier to work with, and you can create smooth surfaces easily.

However, if you’re an experienced DIYer with the proper tools, you can repair minor cracks in your fiberglass. Though you should leave serious damage from backing into objects or something falling onto your rig to a professional body repair shop.

Fiberglass filler
This is a fiberglass piece of an RV that was filled with foam before bing covered in new fiberglass.

How Do You Fix Fiberglass Damage?

The process of repairing damaged fiberglass on your RV isn’t an easy one. It takes as much patience as it does skill. Don’t attempt to do this repair if you don’t have the knowledge, experience, or patience. Let’s look at the steps to fix fiberglass damage on your RV.

In general, fiberglass repairs are made by using a fiberglass mat or sheet that is covered with a resin to harden it. Frequently a filler is also used to make the surface smooth and paintable.

Identify Damage And Determine How To Repair

You need to identify the damaged areas and what caused them. If you find something structurally wrong with your RV, you will need to address that as well. Fiberglass sometimes is a structural component, and if you are not experienced in using it, it’s best that the repair is left to an expert.

If you are mainly filling a hole, sometimes this can easily be done with a filler like Bondo. You may still need to build a support structure behind it to hold it in place during the curing process, however.

RV fiberglass

Gather Supplies

Repairing fiberglass requires many steps and quite a few supplies here is what you will need to get the repair done with fiberglass.

  • Fiberglass resin and hardener
  • Fiberglass mat or cloth
  • Respirator mask or air-purifying respirator
  • Gloves
  • Mixing cups and stir sticks
  • Scissors or a utility knife
  • Sandpaper (various grits)
  • Plastic sheeting or drop cloth
  • Plastic squeegee or putty knife

Put on Safety Gear

When working with fiberglass, it is important to know the hazards and take the following safety precautions. Wear personal protective gear (PPE) such as a respirator mask or air-purifying respirator, gloves, and protective eyewear to avoid inhaling fibers and coming into contact with skin-irritating chemicals. In addition to PPE make sure you have good ventilation in your workspace. The chemicals that vaporize during the process are very harmful to breathe.

Fix Other Damage Under the Surface First

Depending on your RV fiberglass exterior damage and the severity, you may need to repair damage on the outside and inside. Additionally, you could have damage to the insulation in the wall. 

If that’s the case, expanding foam insulation can do the job. Just avoid trying to seal everything up too quickly. Make sure to give it plenty of time to dry.

RV fiberglass Damage
Carefully go through each step of repairing fiberglass to ensure you don’t cause more damage.

Clean and Sand Around the Affected Area

Now that you’ve fixed any secondary damage, it’s time to fix the fiberglass. Start by wiping the entire area as clean as possible. Remove dirt, grime, and any bugs or other foreign substances from the surface.

Once you have cleaned the surface, sand it down to create a level plane. This will help remove any loose pieces of fiberglass from the exterior and create an ideal surface for your compounds.

Apply New Fiberglass

Once the surface is clean and level, you can start applying the fiberglass sheets. First Cut the fiberglass mat or cloth to the appropriate size for the repair. Make sure to wear gloves and a mask when handling the fiberglass.

Next, mix the resin by following the manufacturer’s instructions to mix the fiberglass resin and hardener in the correct proportion. Use a plastic squeegee or putty knife to apply the mixed resin to the repair area. Then, lay the cut fiberglass mat or cloth on top of the wet resin.

fiberglass sheets
Fiberglass Sheets are the best way to apply fiberglass for a repair

Fill in the damaged area and reshape it to its original form. Since most of the fiberglass surfaces on an RV are relatively flat, you don’t need an artist to accomplish this step. Apply more mixed resin on top of the fiberglass, making sure to saturate it completely. Use a roller or brush to smooth out any bubbles or wrinkles.

Allow the repair to cure for the amount of time recommended by the manufacturer. This may take several hours or overnight, depending on the product used.

Sand, Clean, and Paint

Once the epoxy or resin has had time to cure, it’s time to sand it. You want to work slowly and carefully when sanding down the surface. You want to be especially careful when working with corners or any minor curves in the surface. If you work too quickly, you could damage the surface and have to start the process over.

Finish it off with at least 220-grit sandpaper. Ensure you have a surface level, then apply any paint to blend in the damaged area. If you need an exact color, you can contact your manufacturer. You could get the color code from them or order some from them.

Polish

To polish RV fiberglass, let the paint dry thoroughly. Next, apply a coating of polish to the surface. A marine/RV fiberglass restoration system can help you get that bright shine and watch as any remaining signs of damage disappear. 

If you did the job correctly and skillfully, you’ll have no obvious signs of any previous damage. However, cut yourself some slack if you can still tell. You’re not a professional, and this is a tough project. 

You may feel overly critical of the damage as you know exactly where to look. Ask someone who hasn’t seen the damage before and see if they can find it.

Sale
Meguiar's M4965 Marine/RV Fiberglass Restoration...
  • BOAT FIBERGLASS REPAIR KIT: 1 Meguiar's Marine/RV Fiberglass...
  • OXIDATION REMOVER: Heavy duty cleaner safely removes moderate...
  • BOAT POLISH: Rich polishing oils create a brilliant, high-gloss...

Pro Tip: Not sure if a fiberglass camper is right for you? Check out these 5 Reasons Why People Love Fiberglass RV Campers.

Fiberglass Polishing
Be prepared to use a lot of elbow grease to get your fiberglass RV shining like new.

How Do You Restore the Shine on a Fiberglass RV?

If you want to restore the shine on a fiberglass RV, it will take some time and a lot of work. You may need to remove the oxidation on the surface of the fiberglass. The only way to do this is to use some elbow grease and polishing compound. 

You’ll need to work the polish into the surface, then let it dry and create a hazy look over the area. Once this occurs, wipe the surface clean, and it should reveal a shiny surface. Ensure you use a quality marine or RV-grade wax to keep your fiberglass shining as long as possible.

–> Pro Tip: We have a whole article about restoring the shine of your oxidized RV fiberglass.

What Is the Best Polish to Use on an RV?

One of the best polishes to use on an RV is Meguiar’s M4516 Marine/RV Polish and Gloss enhancer. Using this polish regularly on your RV’s fiberglass surfaces will help keep it looking great for years. You’ll get a long-lasting shine and protection on the exterior of your RV.

Sale
Meguiar's M4516 Marine/RV Polish & Gloss Enhancer...
  • RV/MARINE POLISH: Contains rich polishing oils to feed and...
  • OPTIMAL GLOSS: Produces optimal gloss on gel coat and fiberglass...
  • POLISHING STEP: An excellent polishing treatment to apply after...
Remove Oxidation and Restore Faded RV Fiberglass Meguiars One Step

Is Repairing Fiberglass on Your RV on Your Own Worth It?

Repairing fiberglass exterior damage on your RV can be a challenging and risky task. And the procedure we laid out are general steps and may vary depending on the specific repair and product used.

However, you must know which repairs you can handle and which you need to leave to a professional. You’ll likely want to leave severe fiberglass damage to a professional. 

If it’s minor cracks in the surface of your rig, you can likely handle it. Take your time, and don’t rush any step in the process. You just might surprise yourself with the results.

Have you ever had to repair fiberglass on your RV? Tell us your tips in the comments!

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About Mortons on the Move

Tom & Caitlin Morton of Mortons on the Move gave up the stationary life for one where they are constantly on the move. They are full-time travelers, television hosts, and digital media producers.
They left their jobs, sold their house and possessions, and hit the road in September 2015 in their full-time “home on wheels”. Since then they have traveled the US, Canada, and even internationally by RV.
Now, they are Discovery Channel & PBS TV Co-stars of The RVers, producers of “Go North” on Amazon Prime, co-founders and instructors of RV Masterclass, and contributing authors for Hwy.co and an Arizona travel guide.

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Mark

Sunday 29th of January 2023

Love your articles K & T We had a crack / tiny holes in our new to us Keystone Raptor. After removing the body molding we noticed why it was starting. When the unit was built it had a S curve style cut along the wall piece. Not an even cut. Crappy job from the factory grr… After prepping and doing all the repairs needed ie: making the joint square it was finished nicely. Too bad the factory didn’t correct it then before gel coating.

Also Tom, you being an Electrical guru, who in their right mind would design a 50 amp connection less than 2” from the water connection??? Then put the Generator Transfer switch underneath the water line??? You can’t do that building a stick built home. I found this out by having to locate and replace the generator transfer switch. It’s no longer under the water connection.

Mortons on the Move

Wednesday 8th of February 2023

Thanks for your comment, ugh sorry you had to go through that but it's so common to end up finding factory failures long after. I don't think I have seen an RV that I haven't found some stupid factory error on when i really start digging. That does sound really stupid on the power connections. I don't believe the RVIA has spacing requirements for power but you would think it should be common sense!

Doug Merkle

Thursday 26th of January 2023

It is important to note that waxing products containing petroleum distillates are damaging to the decals. I use Meguiars marine products on fiberglass roof and Meguiars ceramic synthetic products on the side. Both products work exceptionally well.