A Step-by-Step Guide to RV Fiberglass Repair and Maintenance

Fiberglass is a preferred material in RV construction due to its lightweight nature, durability, and resistance to rust. However, like any material, it requires maintenance and occasional repairs to keep it in good shape. The good news is that you don’t need professional services to restore and protect your RV’s fiberglass—many tasks can be done yourself with the right approach.
This guide covers everything you need to know about cleaning, restoring, and repairing fiberglass to extend its lifespan and maintain your RV’s condition.

Common Fiberglass Issues

Despite its durability, fiberglass is not immune to damage. Oxidation occurs when sun and air exposure cause the protective gel coat to break down, leading to a dull, chalky surface. Cracks and chips may develop from road debris or general stress, allowing moisture to seep in and cause structural damage if left unattended. Yellowing is another common problem, often caused by prolonged UV exposure. Over time, moisture trapped between fiberglass and plywood layers can lead to delamination, creating bubbling or peeling that becomes costly to fix. Spotting these issues early can save you from expensive repairs later on.

Cleaning RV Fiberglass the Right Way

Regular cleaning does more than just keep your RV looking good—it helps prevent oxidation and long-term damage. However, using the wrong cleaning products can strip away protective coatings and cause more harm than good. Stick to RV or marine-grade soap, as household detergents can be too harsh. A soft-bristle brush or microfiber cloth prevents scratches, while a white vinegar and water mixture can help remove stubborn stains and yellowing. Adding a non-abrasive polish after washing restores shine and adds a protective layer.

Start by rinsing your RV thoroughly to remove loose dirt and debris. Apply soap using gentle circular motions, working in sections. Rinse again to remove any residue that could cause streaking. Drying with a microfiber cloth prevents water spots, and applying a wax or protectant preserves the shine while acting as a barrier against oxidation. Regular washing, especially after long trips, prevents dirt buildup that accelerates wear.

Restoring Fiberglass That Has Lost Its Shine

If your RV’s fiberglass looks faded or dull, oxidation is likely the cause. Mild oxidation can be treated with a fiberglass polish or oxidation remover applied in circular motions with a microfiber cloth or buffer. Heavier oxidation requires a rubbing compound to strip away the damaged layer, applied with an electric buffer for even results. Once the oxidation is removed, follow up with polish and wax to restore the finish. Keeping up with wax applications every few months helps prevent oxidation from returning.

Repairing Cracks, Chips, and Other Surface Damage

Even small cracks can lead to serious water damage over time, so addressing them early is crucial. A fiberglass repair kit containing resin, hardener, and filler, along with sandpaper (220- to 800-grit), acetone, gel coat repair compound, and microfiber cloths, is essential for DIY repairs.
Start by cleaning the damaged area with acetone to remove dirt and wax. Sand the crack or chip with 220-grit sandpaper to smooth the edges and create a bonding surface. Mix and apply the fiberglass filler, following the instructions on your repair kit. After it cures, sand it again using progressively finer sandpaper until smooth. Apply a gel coat repair compound to restore the glossy protective layer, then buff and wax the area to blend the repair seamlessly with the rest of the surface. If moisture has already seeped into the damage, or if the crack is more than surface deep, professional repair may be necessary.

Preventing Future Fiberglass Damage

Proper maintenance keeps your RV’s fiberglass in top condition and prevents costly repairs. Storing the RV under cover or using an RV cover reduces sun exposure and oxidation. Reapplying wax every four to six months protects against UV rays and dirt buildup. Regularly inspecting seals and seams allows you to catch small leaks early, preventing expensive delamination repairs. Washing your RV after long trips removes road grime, bugs, and tree sap that can wear down the gel coat if left too long. Being proactive with maintenance saves time, money, and hassle in the long run.

When to Seek Professional Help

Not all fiberglass issues can be fixed with DIY methods. If your RV has large cracks or holes affecting the structure, widespread delamination, deep water damage, or severe oxidation that won’t respond to buffing, it’s best to seek professional help. In many cases, a professional repair can be more cost-effective than multiple DIY attempts.
Maintaining and repairing RV fiberglass might seem overwhelming, but tackling it step by step makes a significant difference. Regular cleaning, waxing, and minor repairs prevent costly damage over time. Whether you’re fixing a small crack or restoring a faded surface, a little effort keeps your RV looking great and performing well for years to come.