How long do skylights typically last?
Short answer. Most modern glass skylights typically last around 15 to 25 years before the seals, flashing or glazing need replacing, while older plastic dome skylights often wear out sooner as the acrylic yellows and cracks. In practice a skylight's useful life tends to line up with one roof cycle, which is why replacing them together makes sense.
Typical lifespan by type
- Acrylic or polycarbonate domes: common on older homes. UV makes the plastic yellow, craze and turn brittle, and the seals dry out, so many are near the end at 10 to 15 years.
- Insulated glass deck-mounted units: modern skylights with tempered or laminated low-E glass, often good for 20 years or more when flashed with a factory kit.
- Venting skylights: the glass lasts as long as a fixed unit, but motors, cranks and gaskets may need service sooner.
- Tubular daylighting devices: a simple dome over a reflective tube; the dome is the wear item.
What actually fails first
- The flashing. Especially site-built flashing that depends on caulk, the joint between skylight and shingles usually goes first.
- The glass seal. Insulated glass can lose its seal, letting moisture fog between the panes.
- Gaskets and weatherstripping. Rubber parts harden in Georgia heat.
- The curb and framing. Wood curbs rot when small leaks go unnoticed.
Why timing with the roof matters
A skylight flashing kit is woven into the shingles. If the roof is replaced and an old skylight stays, the new shingles are tied into a unit that may fail halfway through the new roof's life, and fixing it then means cutting into new shingles. When a skylight is already past 15 years at the time of a reroof, replacing it is usually the smarter move. See replacing a skylight with the roof and how long a roof lasts in Georgia.