How to Repair a Hole on a Fiberglass Corrugated Roof
A material with a thickness of only .032-inch doesn't seem as if it would make a very good roof, yet corrugated fiberglass panels are among the most popular choices for patios and decks. The translucent panels are light, cost-effective and tough enough to endure most of what nature throws at them. That's not to say they're indestructible, though. Objects such as large hailstones or tree branches can damage fiberglass, especially after it's spent a few years baking under the sun. While big holes may require panel replacement, you can repair those smaller than 3 inches with a custom-made fiberglass patch.
Spread a drop cloth to protect the area beneath the repair. Position a ladder so that the hole in the roof is within easy reach. Remove any loose pieces of fiberglass clinging to the hole. Clean the fiberglass with household cleaner and paper towels.
Roughen the fiberglass around the hole slightly using fine sandpaper. Wipe the area with a paper towel dipped in alcohol. Allow the surface to dry thoroughly.
Cut a piece of fiberglass cloth approximately 1 inch larger all the way around than the size of the hole. Cut another piece 2 inches larger. Place the pieces on a flat, protected work surface.
Put on eye protection and rubber gloves. Pour an amount of polyester or epoxy resin sufficient to coat the pieces of fiberglass cloth into a disposable mixing container. Add catalyst in the proportion recommended by the resin manufacturer. Mix the resin thoroughly for the recommended time with a wooden stir stick.
Pour a portion of the prepared resin onto the smaller piece of fiberglass cloth. Hold the cloth still with a gloved finger as you spread the resin over it using a disposable paint brush.
Apply a thin coat of resin to the fiberglass around the hole with the brush. Immediately press the smaller piece of resin-saturated cloth into position over the hole. Smooth the edges of the patch around the hole with the tip of the brush. Keep the patch from dripping and sagging by working it with a flexible rubber squeegee until the resin starts to harden. Smooth the surface of the patch from the center out toward the edges, removing as many air bubbles as possible.
Prepare the larger piece of cloth by saturating it with resin. Dab it into place using the tip of the brush, covering the first patch. Smooth out the saturated cloth from the center out toward the edges using the squeegee.
Allow the fiberglass patch to cure completely.
- Repair larger holes by overlaying them with a section of matching fiberglass panel glued in place with epoxy; while smaller cracks and holes with a diameter less than the thickness of a pencil are more easily filled with a dab of UV resistant silicon caulk.
- If the hole is readily accessible from above, you can make repairs on the top side of the panel as well, as long as you take care not to put too much weight on the panel or support structure in the process. Smooth the resin out carefully at the edges so that water will flow unimpeded over the repair.
- The supplies necessary to repair holes in fiberglass panels are available separately or in kits. In addition to home centers, look for them in stores that cater to boating and recreational vehicle enthusiasts, as well as auto body and auto parts stores.
- If you are sensitive to epoxy or polyester resin, wear a fume-rated respirator and protective clothing in addition to rubber gloves.
- Always use caution when making repairs from an elevated position, such as on top of a ladder, and never try to walk on a corrugated fiberglass roof.
Steve Hamilton has been writing professionally since 1983. His credits include novels under the Dell imprint and for Harlequin Worldwide. A remodeling and repair specialist with over 20 years experience, he is also a Certified Pool Operator and holds an EPA Universal refrigerant certification.