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How to Repair an Acrylic Skylight

Hugh Patterson

Acrylic skylights are a safe way to bring additional lighting into a space. Their biggest advantage is that their potential for breakage is less than glass. However, because acrylic is not as hard as glass, it tends to scratch more easily. Unlike glass, cracks in acrylic can be repaired with acrylic solvent cement.

Skylights allow extra light into a room.

Scratched acrylic skylights can be polished out, giving them a "new” look. Very few professionals repair acrylic skylights, opting to replace them instead. Skylights are expensive to replace, but using a few tools and inexpensive glues, acrylic skylights can be repaired easily.

Tip

Products like household window cleaners should be avoided when washing the skylight. They contain either alcohol or ammonia, which can damage acrylic over time. Tape old plastic bags around areas being cemented to avoid spilling the solvent cement onto the skylight surface. Don't use paper, because the solvent cement can bleed through the surface and damage the acrylic.

Warning

Always use caution when working on a roof. If the area is hard to reach, call a professional.

  1. Wash the outside surface of the skylight with water and a mild dishwashing detergent. Examine the cleaned surface to determine where the damage is. Cracks tend to form in corners or other areas of stress, such as holes drilled for screws. Scratches tend to form across the center of the skylight, due to falling debris.

  2. Buff the exterior of the skylight with an acrylic polishing compound to remove light scratches from the surface and help expose any cracks that need to be glued. Apply a small amount of the buffing compound to the skylight’s surface. Using a 100 percent cotton rag, rub the compound over and around the scratches. Wipe off any residual compound left on the surface.

  3. Tape off the areas around any cracks, using painter’s masking tape, to avoid spilling acrylic solvent cement on the skylight's surface, which can scar the acrylic.

  4. Fill the squeeze bottle applicator to the half-way point with acrylic solvent cement. Squeeze the bottle until the cement is near the bottle’s top. Slightly release your finger pressure on the bottle. This creates a vacuum, which keeps the cement from pouring out when the bottle is inverted. Place the needle against the crack. Squeeze a thin bead of cement into the gap, following the crack. Repeat the process for any additional cracks.

  5. Remove the painter’s masking tape. Let the cement dry for 24 hours.

  6. Buff any residual cement off with the acrylic buffing compound. Wash the skylight again.

  7. Check the caulk around the base of the skylight for damage. Roofs get extremely hot during the summer months, which can cause the caulk to separate from the space between the skylight and the frame holding it to the roof. Water can leak through this tiny gap. Run a fresh bead of caulk around this joint, using the caulk gun. If the old caulk is beyond patching, pull the old caulk up and apply a fresh bead. Let it dry. Inspect the caulk to make sure the gap around the joint is sealed.