Skylight Leaking After Cleaning? Why It’s Usually a Flashing Issue
A skylight that starts leaking right after a cleaning visit can feel like an obvious connection. In almost every case, the timing is a coincidence. The cleaning did not cause the leak. It just happened to reveal one that was already there.
Why Cleaning Gets Blamed
Water finding a new path is the usual trigger. A cleaning visit means water running across the roof and around the skylight frame. This does not happen the same way during a quick rain. That extra water flow can push through a gap that was already there. It just had not leaked yet, since water had not reached that spot before.
What Actually Causes Most Skylight Leaks
Flashing is the metal or rubber material sealing the edge where a skylight meets the roof. It directs water around the skylight, not through it. Flashing wears down over years of sun exposure and roof aging. Once it cracks or pulls away even slightly, water finds a way in during any wet event. This happens whether cleaning is involved or not.
Other Common Causes Unrelated to Cleaning
| Cause | Why It Leads to Leaks |
|---|---|
| Cracked or worn flashing | The primary water barrier fails over time |
| Deteriorated sealant | Old caulk shrinks and separates from the frame |
| Roof damage near the skylight | Nearby shingle or tile damage lets water reach the frame |
| A failed skylight seal | On double pane skylights, this lets moisture in between the panes |
How to Tell the Difference
A cleaning related issue would show up right away. Water used during the service would find its way in immediately. A flashing or sealant issue usually shows up during the next rain instead. Sometimes it takes days or weeks. It also tends to happen again with any real rainfall afterward, not just once.
What a Professional Should Do
A window cleaner working on skylights should never use pressure washing or heavy water volume. Standard skylight cleaning uses controlled amounts of water. It should not add more moisture than a typical rain event would. If a leak appears after cleaning, a pre-existing flashing issue is the more likely cause. The added water flow just happened to reveal it.
What to Do If You Notice a Leak
Write down when the leak started. Note whether it lines up with rain or with a cleaning visit. This helps a roofer diagnose the real cause faster. A roofing professional should inspect the flashing and sealant. That repair falls outside what a standard window cleaning service handles.
Frequently Asked Questions
Can excess water from cleaning really cause a leak on its own?
It is very unlikely for a properly sealed skylight. Cleaning water alone rarely equals the volume of a real rainstorm.
Should I stop having skylights cleaned if one leaked afterward?
Not necessarily. The more useful step is having the flashing and seals checked. That is almost always the actual source of the problem.
How often does flashing typically need replacement?
It varies with material and climate. Many roofing sources suggest checking flashing every few years, since it wears down before most other roofing materials.
We Clean Carefully, No Guesswork
ClearCraft Window Cleaning uses controlled water volume on every skylight visit, and we will always point you toward a roofer if we spot a flashing issue.