Skylight Leaks: Causes Damage and How to Repair Them

Skylight leaks usually start at the flashing, the metal or rubber pieces that seal the gap between the skylight and your roof. Over time, flashing can crack, pull away, or have failed seams. Another frequent culprit is the rubber gasket around the glass, which can dry out and shrink, allowing water to sneak in.

Improper installation is another cause. If the skylight was not flashed correctly or the step flashing was not integrated with your roofing material, water can find a path. Also, clogged gutters or valleys above the skylight can back water up under the flashing. In wet climates, these areas face extra stress, so check them after heavy rain.

For a temporary fix, you can apply a high-quality exterior sealant around the flashing and seams. Clean the area thoroughly first, and apply on a dry day. This can buy you time, but it is not a permanent solution. For a more lasting repair, you may need to remove the old flashing and reinstall it correctly, or replace the skylight if it is old.

If the leak is from a cracked skylight dome or glass, you may need to replace the glazing. Some skylights have replaceable inserts. Check the manufacturer's instructions or consult a roofing professional. If you are comfortable on a ladder and have basic tools, you can attempt simple repairs, but for complex flashing work, consider hiring a roofer or water damage pro.

Regular maintenance is key. Twice a year, inspect the skylight from the roof and inside the attic. Clear leaves and debris from gutters and valleys. Check the flashing for any signs of wear and reseal if needed. If you have skylights, consider trimming nearby tree branches that might drop debris or rub against the roof.

When you replace your roof, make sure the roofer pays attention to the skylight flashing. It is a common weak point. If you are installing a new skylight, choose a model with a solid build and have it installed by a professional. In a climate with wet winters and dry summers, proactive checks can save you from costly repairs.