A skylight that has never leaked can start leaking a few weeks after a new roof goes on. Stripping old shingles means prying up the flashing that seals the skylight to the roof deck, and twenty-year-old flashing rarely lifts clean. Even when a crew reseals carefully, the original weather seal has been disturbed.
That is why skylight replacement comes up on nearly every roof job we walk in Cumming and across Forsyth County. The question is rarely whether a skylight can survive the roof work. It is whether the unit has enough service life left to be worth putting back into a roof that should last another twenty-five years.
How Long Skylights Last
Skylights age from the seal outward. The glazing, whether glass or acrylic, tends to outlive the gaskets, sealants, and flashing that hold water out. Once those components harden and shrink, water finds a path long before anything looks broken from the ground.
Age matters more than appearance. Units installed before the mid-2000s were often acrylic domes set on a wooden curb, and acrylic clouds, yellows, and grows brittle under sustained UV exposure. Lifespan varies by product, roof pitch, orientation, and sun exposure. A south-facing skylight on a low-slope roof in North Georgia works considerably harder than a north-facing one under tree cover.
One reliable shortcut: if the skylights are older than the roof coming off, they were almost certainly reused during the last roof job. They have been disturbed once already, and a second reuse rarely makes sense.
Signs A Skylight Is Ready For Replacement
| What you notice | What it usually means |
|---|---|
| Haze or condensation between the panes | The insulated glass seal has failed. Resealing around the frame will not bring it back; the glazing has to be replaced. |
| Water stains at the corners of the light shaft | Water is entering at the flashing and traveling along framing before it reaches drywall. |
| Staining that appears only in wind-driven rain | Points to the flashing rather than the unit itself. |
| Cloudy, yellowed, or crazed acrylic dome | UV breakdown. Brittle acrylic cracks under hail, and North Georgia gets enough hail for that to matter. |
| A crank or motor that sticks or will not close tight | Worn hardware. A unit that does not seal is losing conditioned air year round. |
| Hard, chalky gaskets, or daylight visible around the frame from the attic | The weather seal is past its service life. |
Leaks often show up several feet from the actual entry point, which is worth understanding before deciding what to replace. We go through that in more detail when diagnosing a leaking skylight.
Why Roof Replacement Is The Moment To Handle It
Flashing is the reason. A skylight is sealed to the roof by a layered flashing system that has to be woven into the shingle courses in a specific order, each piece lapping the one below it. That sequence can only be built correctly when the deck is open and the shingles are going on fresh.
Re-flashing an existing skylight means working new flashing around a unit that stays put. On a newer skylight in good condition, that is a reasonable call. On an older one it means disturbing seals that were never designed to come apart and go back together.
Sequencing cuts the other way too. If a reused skylight fails in year four of a new roof, replacing it means opening shingles that are no longer available in the same production run, and the patched area rarely blends.
Warranty terms are worth checking before you decide. Coverage is generally tied to a unit being installed with its matching flashing kit according to the manufacturer's instructions, so re-flashing an older unit or reusing a flashing kit may fall outside those terms. Terms differ by brand and product line, so read your own documentation rather than assuming. Some roofing contractors will also reuse skylights only with a signed waiver releasing them from responsibility for later leaks in that area, which is worth asking about before work starts. As a VELUX Certified Installer, we install each unit with its matched flashing system, and the specifics of VELUX warranty coverage are worth reviewing while you are still deciding.
Curb Mount And Deck Mount Skylights Are Not Interchangeable
| Deck mounted | Curb mounted | |
|---|---|---|
| How it sits | Directly on the roof deck, with integrated flashing close to the roof plane | On top of a built-up wooden curb, typically four to six inches tall |
| Usually found on | Newer glass units | Older domed acrylic units |
| Switching to the other type | Requires building a curb | Requires removing the curb and reframing the opening |
Older homes sometimes have rough openings framed to dimensions that no longer match standard manufactured sizes, which narrows the options. Sort this out during the consultation rather than on the day the roof crew arrives, since it changes both the framing work and the lead time on the unit.
What The Replacement Itself Involves
- We walk the roof and the interior, checking the flashing, shaft, and framing, and confirm the mount type and rough opening dimensions.
- We help select a unit suited to the room, the roof pitch, and how much light and ventilation the space needs. Our skylight installation work covers fixed, manual venting, solar-powered, and electric units, plus flat roof and architectural applications.
- The old unit comes out and any deck or framing damage underneath gets addressed.
- The new skylight is set and the flashing is built into the roofing as the shingles go on.
- Inside, the shaft is framed, insulated, and finished to blend with the ceiling. We test for leaks, review operation on venting units, and clean up.
For finished attic and bonus room spaces where you want something you can reach and open like a standard window, roof window installation is often the better fit, and that decision is easier to make before the roof work is scheduled.
Have The Skylights Assessed Before Roof Work Begins
Once the shingles are on, the window for handling skylights without additional tear-out has closed. If you have a roof replacement coming up in Cumming or anywhere across Forsyth County, have the skylights looked at while the plan is still being made.
Forsyth Exteriors has been installing and replacing skylights in North Georgia homes since 1993. Call 770-887-8646 or schedule a free consultation, and we will assess what you have and tell you honestly whether it needs replacing.
