How long does a skylight last?
Short answer. A skylight usually lasts about 15 to 25 years, with quality glass units at the longer end and plastic domes at the shorter end, though the flashing around it can fail sooner if it was not installed with a proper kit. Fogged glass, recurring stains around the shaft, cracked or yellowed plastic and rotting curbs are signs a skylight is near the end.
Signs your skylight is done
- Fog between the panes. The insulated glass seal has failed, the unit has lost efficiency, and the haze will not wipe off.
- Yellowed, crazed or cracked plastic. Old domes become brittle, and hail can shatter them.
- Recurring stains on the drywall shaft or the ceiling around the skylight.
- Soft or dark wood on the curb or framing, visible from the attic.
- Venting units that will not close tight or have failed motors.
Drips that appear only on cold winter mornings may be condensation rather than a leak, so check humidity and ventilation before replacing anything.
Maintenance that stretches its life
- Keep leaves and pine needles off the uphill side, where debris dams water against the flashing.
- Clean the glass gently with mild soap, never with a pressure washer.
- Have the flashing and seals checked during roof inspections and after hail.
- Run the bathroom fan to cut condensation on skylights in wet rooms.
Repair or replace?
Flashing leaks can often be repaired if the unit is sound and the roof is young. A failed glass seal, cracked dome or rotted curb means replacement. If the roof is due within a few years, wait and do both together so the new unit is flashed into new shingles. Hail damage to skylights can be part of a storm claim, so photograph cracks right after a storm. See replacing a skylight with the roof and common causes of roof leaks.