Crack, Hole and Impact Repair: Cost, Hours and Process in Hacienda Heights

The first thing we establish is depth, because it changes everything downstream. Gel coat is a resin rich surface layer with no reinforcement in it, and it crazes on its own from age, flex and UV. Crazing that stops at the gel coat is a surface repair. A crack that has gone through into the reinforcement is a structural repair, and treating the second like the first is the single most common reason a fiberglass repair fails.

The tell is white. Cured polyester and epoxy are translucent when intact and turn opaque white where fibers have broken away from resin, so a crack with a white halo is through the laminate whether or not it feels solid. The other tell is flex. Press either side of the crack: if the two halves move independently, the reinforcement is not carrying load across that line.

A third case sits between them and gets misread constantly. Print through and stress crazing along a fastener row or a bracket mount is not impact damage at all. It is the laminate telling you that something is loading it in a way it was not laid up for, and filling it without addressing the bracket produces the same crack in the same place next year.

Fiberglass carries load through fiber, and a repair only carries load if the new fiber overlaps the old across enough distance to transfer it. That means grinding a taper. The rule of thumb is twelve to one: for every unit of laminate thickness, the bevel extends twelve units back from the break. On a ninety thousandths skin that is around an inch of taper on each side of the crack, and on a thicker molded cap it is considerably more.

So a six inch crack becomes an eight inch repair area before a single layer goes down, and the finished refinish zone is wider still. Owners see the ground area and assume the shop is inflating the job. The opposite is true: a repair ground back only to the crack itself has no overlap, and it cracks again at the boundary of the patch.

Layup then goes in as successive plies rather than one thick pour. Chopped strand mat first for conformability and resin bond, woven roving or biaxial cloth where the area needs strength across a specific axis, and each ply wet out and rolled to drive air out before the next goes on. Trapped air is a void, and a void in a repair is a crack that has not happened yet.

• Twelve to one taper ground back from the break on both faces where access allows
• Backing laminate applied from the reverse side wherever the panel can be reached
• Chopped strand mat first, then cloth or biaxial oriented to the load
• Each ply wet out and rolled to eliminate trapped air
• Fairing compound only after the laminate is built back to full thickness
• Refinish and blend handled as a separate paint department line

Most RV exterior laminate is polyester based, and polyester is what the factory used. It is inexpensive, it bonds well to itself while green, and it is the correct choice on a fresh layup or a panel being fabricated. On a repair to eighteen year old cured laminate it is the weaker option, because polyester bonds to fully cured polyester mechanically rather than chemically.

Epoxy is what we reach for on structural repairs to aged laminate. West System is the system we stock. It bonds to cured polyester far better than polyester does, it shrinks less on cure, and it is more tolerant of a repair that has to survive flex. The tradeoff is that polyester gel coat does not like to be sprayed over epoxy, so the finish schedule changes and the refinish gets planned before the layup starts rather than after.

Cure is the constraint that keeps this in a building. Resin cure is temperature dependent at both ends. Too cold and it never reaches full properties, so the repair is soft and the crack telegraphs back through within a year. Too hot and a thick layup exotherms, which distorts the panel and can leave the repair area standing proud of the surrounding surface. A controlled bay is not a nicety on this work, and it is the reason fiberglass repair is not something we take out to where the coach is parked.

An impact into a laminated wall does two things. It breaks the skin where it hit, and it sends energy outward through a bonded assembly that does not tolerate shock well. The second one is invisible on day one and is the reason we read the area around the damage before writing the repair.

In practice that means a raking light pass and a tap test out to a foot or more past the visible break, looking for a ring of bond failure around the contact point. It also means a moisture read, because a crack that has been open through one rainy season has been feeding water into luan the whole time and the substrate condition changes the scope.

On a molded cap, we also look at what the cap is fastened to. A strike at the lower corner of a front cap transfers into the mounting flange and the framing behind it, and a repair that puts the fiberglass back over a bent flange leaves a stress riser that cracks the new laminate. If any of that shows up, the honest scope is larger than the visible damage and we write it that way, with photographs, so the difference is documented for your carrier rather than argued at the counter.

The band on this page runs from a single contained crack in a flat skirt at the low end to a punched through cap with bond failure around it and a damaged mounting flange at the high end. Labor is the posted body and paint rate of $210 per hour across four to sixty plus hours, and body supplies add $5 per body hour on top of resin, mat and cloth.

The refinish is the part that surprises people on cost. A structural repair can be perfect and still be visible, because the surface has to be faired flat, sealed, and then either gel coated or painted and blended into a panel that has been fading in Southern California sun for a decade. On a white coach that blend is manageable. On metallic paint or a graphics field crossing the repair, the refinish can exceed the layup.

One honest boundary: not every cracked panel should be repaired. Where a skin is crazed across most of its area, or where the same panel has already been repaired twice, replacement is the cheaper answer over any reasonable horizon and we will say so rather than sell a third layup.