Skylight moisture problems come in three common forms:
- Condensation on the inside: indoor humidity meets a cold surface.
- Fogging between panes: the insulated glass seal has failed.
- True roof leaks: flashing or curb details allow water in during storms.
Each needs a different fix—so the first step is identifying which one you have.
1) Condensation on the interior glass
This is usually a humidity/ventilation issue. It’s common in bathrooms, kitchens, and tightly sealed homes.
Fixes that work
- Use exhaust fans consistently (and verify they vent outside)
- Improve indoor humidity control
- Upgrade ventilation to reduce attic moisture accumulation
2) Fogging between panes
If the skylight looks “cloudy” between layers of glass, the seal has likely failed. In many cases, the durable fix is replacing the skylight or glazing unit.
3) Water stains or dripping during storms
This points more toward flashing/underlayment details. Caulk rarely solves it long-term. The correct fix rebuilds the flashing system and ties it into the roof properly.
What to check (homeowner-friendly)
- Does moisture show up only in winter mornings (condensation) or during rain (leak)?
- Is staining localized to one corner of the skylight curb?
- Are there nearby roof features (valleys, walls) that concentrate water?
Repair vs replacement
Repairs are often effective when the skylight itself is fine but the flashing is failing. Replacement is often smarter when the unit is old, fogged, or inefficient. Read our deeper guide: Skylight repair vs replacement.
Next step
If you want leak-free daylight, explore skylights and request an inspection for clear options.