# Fiberglass and Delamination > Laminate, gelcoat and substrate repair for RV and commercial body panels, from hairline surface cracks through full sidewall reskin. Source: https://ocrv.info/services/fiberglass-and-delamination Laminated body panels fail differently than sheet metal. A fiberglass sidewall is a sandwich: gelcoat or filon on the outside, a thin fiberglass skin bonded to lauan plywood or Azdel composite, block foam and framing in the core, then an interior wall board. Damage rarely stops at the surface. A cracked corner or a leaking seam moves water into the core, the adhesive bond releases, and what looked cosmetic becomes a structural repair. OCRV Center works on these panels inside a 35,000 square foot facility at 23281 La Palma Ave in Yorba Linda. Owners from Eastvale reach the shop in roughly half an hour, taking SR-91 west or dropping down SR-71 from the I-15 corridor. Everything happens in the building. Laminate work needs controlled temperature for resin cure, dust containment for grinding, and enough covered bay length to open a forty foot coach without moving it twice. Six services sit under this category, and they overlap on purpose. A blister field on a front cap might be gelcoat work alone. The same coach with a soft spot under the window belt may need the skin peeled, the substrate replaced and a new panel bonded. Diagnosis comes first: moisture meter readings across a grid, tap testing along seams and corners, and thermal imaging when a void does not read acoustically. Scope follows the findings, not a guess. ## How do you tell cosmetic fiberglass damage from structural damage? Press on it. A sound laminate feels dead solid and returns a sharp tap when struck with a plastic mallet or a coin. Panel that has lost its bond sounds hollow, drums under light pressure, and often shows a shallow bulge or a ripple visible only in raking light. That difference decides whether the job is a surface repair or a rebuild, and it is the first thing checked on any coach coming in from the I-15 corridor. Moisture is the second gate. A pin meter reads relative moisture through the skin at fastener lines, window corners, roof seams and the lower belly band. Readings that climb as the probe moves toward a seam point at an active leak, which means water intrusion gets corrected before laminate goes back on. Sealing new glass over a wet lauan core traps the problem and buys perhaps a season before the repair lifts at its edges. The third check is dimensional. Sight down the sidewall from the rear corner. Waves, oil canning and a rolled edge at the belt line mean the substrate has swelled or the framing behind it has moved. Cosmetic repair cannot pull a swollen panel flat, so that observation changes the estimate before any grinding starts. Sighting from both ends catches a twist that a single viewpoint misses, and a straightedge laid across the belt line confirms it. - Hollow or dull response under tap testing across a mapped grid - Pin meter readings that rise toward seams, windows or roof edges - Visible bulge, ripple or wave in raking light along the sidewall - Spider cracking radiating from fastener holes and mount points - Gelcoat that chalks white and transfers to a hand wiped across it - Soft, spongy feel underfoot on a walkable roof section ## Which resin and reinforcement go into an RV panel repair? Original equipment sidewall skins are usually a polyester laminate, sometimes a filon sheet, bonded with a urethane or polyurethane adhesive to the backer. Repair resin selection follows what the panel is and what the repair has to do. Orthophthalic and isophthalic polyester with MEKP catalyst handles most cosmetic and light structural work and stays chemically compatible with the original layup. Vinylester goes in where water contact and fatigue resistance matter, such as lower sidewalls and wheel well surrounds. Epoxy earns its place on secondary bonds. Grinding into a fully cured panel means the new laminate can only form a mechanical and partial chemical bond to old resin, and epoxy holds that interface better than polyester does. The tradeoff is that gelcoat does not cure reliably over epoxy, so any epoxy repair gets a barrier step or a different topcoat plan. Choosing the wrong combination shows up months later as a ghost outline around the patch. Reinforcement is layered by function. Chopped strand mat conforms and builds thickness. Woven roving and biaxial cloth carry tensile load across a break. A structural repair alternates them, orienting the cloth so fiber runs across the direction of the crack rather than parallel to it. Thickness is built to match the original skin instead of exceeding it, since an over-thick repair becomes a hard spot that the panel then flexes around. - Polyester with MEKP catalyst for compatible general laminate work - Vinylester where moisture exposure and flex fatigue are constant - Epoxy for secondary bonds into cured panel, with a barrier topcoat plan - Chopped strand mat for conformability and thickness build - Woven roving or biaxial cloth oriented across the load path - Peel ply on the final layer to leave a bondable, resin-lean surface ## Services in this category - [RV Fiberglass Repair](https://ocrv.info/services/fiberglass-and-delamination/rv-fiberglass-repair): Structural laminate repair for cracked, punctured or weakened fiberglass panels on motorhomes, travel trailers and commercial bodies. Range $750 to $12,000+, 4 to 60 hours. - [Delamination Repair](https://ocrv.info/services/fiberglass-and-delamination/delamination-repair): Bond restoration for separated RV sidewalls and roofs, from injected voids through full skin peel and substrate replacement. Range $1,500 to $20,000+, 10 to 100 hours. - [Crack, Hole and Impact Repair](https://ocrv.info/services/fiberglass-and-delamination/crack-hole-and-impact-repair): Targeted repair of punctures, gouges, spider cracks and impact breaks in fiberglass RV and commercial body panels. Range $500 to $5,500, 3 to 25 hours. - [Fiberglass Panel Replacement](https://ocrv.info/services/fiberglass-and-delamination/fiberglass-panel-replacement): Full or partial exterior skin replacement for RV sidewalls, roofs and end caps when patching is no longer the right answer. Range $2,500 to $25,000+, 16 to 120 hours. - [Fiberglass Restoration](https://ocrv.info/services/fiberglass-and-delamination/fiberglass-restoration): Multi-stage cut and buff that strips oxidation and chalking from aged gelcoat and returns depth to the original surface. Range $800 to $6,500, 4 to 28 hours. - [Gelcoat Repair](https://ocrv.info/services/fiberglass-and-delamination/gelcoat-repair): Spot repair of chips, gouges, crazing and blistering in the gelcoat layer of molded fiberglass RV components. Range $500 to $4,500, 3 to 20 hours. ## Frequently asked questions ### Is fiberglass repair on an RV the same as boat fiberglass work? The resin chemistry and layup principles carry over, but the construction does not. A hull is a thick solid or cored laminate designed to be structural on its own. An RV sidewall is a thin skin bonded to a lightweight backer, so most of its stiffness comes from the sandwich, not the glass. Repairs have to respect that difference or the patch ends up far stiffer than the panel around it and cracks at its own edge. ### Can you repair a coach that has water damage behind the fiberglass? Yes, though the sequence matters. Wet lauan or saturated framing has to come out and dry structure has to go back before new laminate is bonded over it. The leak source gets corrected at the same time, whether that is a failed roof seam, a window frame, or a compromised marker light penetration. Skipping the moisture step means the repair lifts along its perimeter within a year or two. ### How long does laminate work usually keep a rig in the shop? Resin cure sets the floor. Each laminate stage needs time at temperature before the next one goes on, and fairing, priming and refinishing add their own cycles. A localized crack repair moves quickly. A sidewall that needs the skin peeled, substrate replaced and a new panel bonded and finished takes considerably longer because there are more stages that cannot be rushed without compromising the bond. ### Do you work on travel trailers and fifth wheels, or only motorhomes? Both, plus toy haulers, truck campers, Sprinter and ProMaster conversions, box truck bodies and fleet trailers. Laminated panel construction shows up across all of them, and the failure modes are similar. Towable units actually see more sidewall flex damage than motorhomes because the frame twists differently over uneven pavement, so cracks tend to concentrate at slide-out corners and window openings. ### Will the repair match the rest of the body, or will I see a patch? A properly faired laminate repair should disappear into the panel contour before any finish work begins. Matching the surface appearance is a separate discipline that depends on how much the surrounding gelcoat or paint has aged. Older, oxidized surfaces sometimes need the whole panel or an adjacent break line brought to the same condition so the repaired section is not the only fresh area on the body. --- OCRV Center. 23281 La Palma Ave, Yorba Linda, CA 92887. (949) 799-3387. info@ocrvcenter.com. Serving Eastvale, California in Riverside County, about 20 miles from the shop. All work is performed in shop at the Yorba Linda facility. No mobile, roadside or on-site service is offered. Scope is body, paint, structural, fiberglass, interior and vehicle systems work. Engine rebuilds, transmission rebuilds, drivetrain work, DOT inspections and emission testing are not performed.