Skylights are among the most popular upgrade requests we get from Treasure Valley homeowners, and among the most common sources of roof leaks on existing homes. Done right, a skylight adds natural light and lasts decades. Done wrong, or left unmaintained, it becomes a recurring problem that causes more water damage than the aesthetic value justifies.
Why skylights leak
The most common misconception about skylight leaks is that the glass or frame is the problem. In the vast majority of cases, the leak is a flashing failure at the point where the skylight curb meets the roof surface.
Proper skylight flashing involves a specific sequence: step flashing along the sides woven into the shingles, a saddle flashing at the uphill end to redirect water around the curb, and counter flashing over the step flashing that seals against the curb frame itself. When this sequence is done correctly, the system handles Idaho's freeze-thaw cycling without failure. When contractors take shortcuts -- applying roofing cement as the primary seal rather than mechanically installed flashing layers -- the system fails when the cement cracks or disbonds, often within a few seasons in Boise's climate.
Condensation is sometimes misidentified as a leak. If moisture appears on the skylight frame or glazing interior primarily during cold nights and disappears as temperatures rise, it's likely condensation from interior humidity against the cold surface rather than water intrusion from outside. The distinction matters for how it's addressed.
Repair versus replace
For skylights under 15 years old with a flashing failure, reflashing is almost always the economical choice. The skylight itself is still functional -- the flashing system around it needs to be done correctly. Reflashing a skylight costs a fraction of replacement and solves the leak problem permanently when done properly.
For skylights over 20 years old, particularly those with significant haze in the glazing, frame corrosion, or structural problems from long-term moisture, replacement makes more sense than continued investment in repairs. We assess the skylight and surrounding decking from inside the attic and on the roof surface before making a recommendation. The condition of the decking around the skylight -- which is exposed to any water that has been getting through -- factors into whether repair or replacement is the right call.
Blue Goat Roofing handles skylight repair and replacement throughout Boise, Meridian, Eagle, and Nampa. The best time to install a new skylight is during a full roof replacement -- the integration of flashing with new shingles is done in one operation rather than two, at lower combined cost.