The Slow, Polite Failure
Skylights fail slowly and politely, right up until they leak. The dome yellows, the seal dries, and you stop noticing it the way you stop noticing anything that has been slightly broken for a decade.
The One We Just Replaced
We just replaced one on a lift and relay in Riverside. The old dome was 30 years old and cracked. The new skylight went in during the reroof, and the homeowner's reaction is the reason I am writing this: he could not believe how much light the room had been missing. Modern units also handle heat completely differently. The old acrylic domes let the sun cook the room. Today's skylights are built to bring the light in and keep the heat down, and in a Riverside or Fontana summer that is not a small thing.
What Homeowners Should Know
First, skylights have lifespans, roughly 20 to 30 years, and an original skylight on an older roof is living on borrowed time. Second, the flashing around a skylight is one of the most common leak points on any roof, because it is a hole in your roof by design. Third, and this is the practical part: the best time to replace a skylight is during a reroof. The flashing gets built into the new roof system as one piece instead of patched onto old material, the crew is already up there, and the cost folds into the project instead of standing alone.
Handle Both at Once
We replace skylights on request during any roof project. If your roof is due and there is a sad gray dome up there from the first Bush administration, handle both at once. You will get the bulletproof seal, and a room you forgot could look that bright.