Short answer: No, skylights do not always have to be replaced during a reroof. However, a reroof is often the best opportunity to inspect, repair, reflash, or replace existing skylights. Whether replacement is necessary depends on the skylight’s age, condition, flashing, installation, and expected remaining service life.
When a roofing system is being replaced, skylights deserve special attention because they create an opening in the roof where water intrusion can occur. A skylight that appears to be functioning properly may still have aging seals, deteriorated flashing, damaged components, or outdated glazing.
Why Are Skylights Often Replaced During a Reroof?
Reroofing involves removing and installing roofing materials around the skylight. This work can disturb existing flashing and the skylight assembly. According to VELUX, older skylights can be more susceptible to damage during the reroofing process, and skylights over 20 years old may be particularly vulnerable.
Replacing a skylight at the same time as the roof can also eliminate the need to disturb a newly installed roof later. If an aging skylight starts leaking a few years after the reroof, repairing or replacing it may require removing surrounding roofing materials again.
When Should a Skylight Be Replaced?
Replacement is generally worth considering when the skylight is old, damaged, leaking, or approaching the end of its expected service life.
Signs that may indicate replacement include:
- Cracked, fogged, or damaged glazing
- Water stains or evidence of previous leaks
- Deteriorated seals or gaskets
- Corroded or damaged frames
- Damaged or outdated flashing
- Condensation between glass panes
- Difficulty opening or operating a venting skylight
- A skylight that is significantly older than the surrounding roof
Skylight age is particularly important. VELUX notes that the average skylight lifespan is around 20 years, although some properly maintained models can remain functional longer.
What If the Existing Skylight Is in Good Condition?
A relatively new skylight that is in excellent condition does not automatically need to be replaced simply because the roof is being replaced.
However, the flashing and waterproofing details should be carefully evaluated. In many installations, the flashing system is a critical component of keeping water away from the roof opening. Manufacturers such as VELUX and FAKRO emphasize that properly designed flashing is essential for drainage and weather protection.
If the existing skylight is retained, a qualified roofing contractor should inspect the unit, surrounding roof deck, flashing, seals, and waterproofing before completing the reroof.
Why Replacing the Skylight During Reroofing Can Make Sense
There is a practical advantage to completing both projects together: the roofing materials around the skylight are already being removed.
A skylight replacement typically requires removing surrounding roofing materials and installing new flashing and underlayment. Completing this work during the reroof can reduce duplicated labor and minimize the possibility of disturbing a new roof later.
Newer skylights may also provide improvements in energy efficiency, glazing performance, ventilation, controls, and manufacturer warranty coverage, depending on the model selected.
Does the Flashing Need to Be Replaced?
Even when a skylight itself remains serviceable, its flashing should not simply be assumed to be reusable. Flashing must be compatible with the skylight, roofing material, and roof slope, and it needs to be installed correctly.
For example, VELUX states that its flashing systems are engineered for particular roof materials and slopes and are an important part of its weatherproofing system.
The Bottom Line
Skylights do not always need to be replaced during a reroof, but every skylight should be professionally evaluated before the new roof is installed. If the unit is relatively new and in excellent condition, retaining it may be reasonable. If it is old, leaking, damaged, or has questionable flashing, replacement during the reroof is often the more practical long-term solution.
At Shieldline Roofing, a reroof should be treated as an opportunity to evaluate every roof penetration—not just the roofing material itself. A proper skylight inspection can help determine whether the best option is to keep, repair, reflash, or replace the existing unit, helping protect the new roofing system from avoidable water intrusion.
Related Questions
- Can skylights be permanently removed and infilled during a reroof?
- What causes skylight leaks and how are they diagnosed?
- Does a lightning protection system need to be reinstalled after a reroof?
- How are skylights protected against fall-through?
- What is the difference between a unit skylight and a structural skylight?
- How are skylight curbs raised when insulation thickness increases?
- How do you inspect a skylight without walking on or near it?
- What if my roof is old but still in good condition?
