What to Do About a Leaking Skylight

A leaking skylight can damage the interior of your home and lead to roof rot. You need to fix it as soon as possible.

What to Do About a Leaking SkylightView in gallery

Depending on the cause of the leak, you may be able to repair the skylight yourself. But since defective skylights can cause large amounts of damage, consulting a professional is the best route.

Here’s what to do about a leaking skylight.


Top Reasons Skylights Leak

While it would be convenient if skylight leaks were easy to identify, finding the cause is sometimes difficult. 

These are the five main reasons skylights leak:


Cracks in the glass – One of the most apparent sources of a leaking skylight is cracked glass. If this is the case, you need to replace the entire unit.


Condensation – Condensation forms due to high humidity. It happens when temperatures on the inside and outside of the home have a stark contrast. For example, if your home is warm and humid, and outside is cold, the temperatures meet at the glass, and condensation builds. The condensation then drips into your home.

Condensation is the least problematic issue with skylights. You can fix it by monitoring humidity levels and ensuring proper insulation around the window.


Skylight won’t close all the way – If your skylight is operable, ensure it’s closed all the way. If it doesn’t close, water will leak in. Also, check the rubber gasket around the edge of the glass –  it’s what creates the airtight seal.

If the rubber gasket looks good, ensure no sticks or leaves are preventing the window from closing.


Flashing or weather stripping needs replaced – Flashing is a thin layer of waterproofing material that goes around windows and chimneys to prevent water from entering the home. 

Like flashing, a skylight also has weather stripping around the frame to ensure an airtight seal. When warped or damaged, these materials provide space for water to penetrate.

You can repair weatherstripping and flashing, but it’s best to have a professional do it for you.


Improper installation – If your skylight is new, improper installation may be the culprit. Skylight installation is complicated and not a task to DIY. If the hole for the window isn’t the correct size, the skylight will leak and become a hazard.


How to Identify the Cause of Your Skylight Leak

Inspect your skylight and look for cracks. Replace or remove the unit if you find cracks in the glass. If you decide to remove the skylight, you’ll need to patch holes inside and outside the home.

If you notice beads of water on the inside of the glass, condensation is your problem. Run a dehumidifier and take other steps to reduce the humidity in the room.

If water is leaking in your home from the side of the skylight, the cause is damaged weatherstripping, flashing, or improper installation.

Damaged flashing or weatherstripping are the typical offenders for older models. If your skylight is new, improper installation may be the culprit.


Tips for Fixing a Leaking Skylight

If you notice a leak in your skylight, act fast. Unless the issue is condensation or a glass crack, water may pool on the roof around the edge of the window. When this happens, the roofing decking can rot, leading to severe damage.

  • Contact a professional if you suspect improper installation, damaged flashing, or weatherstripping. Repairing skylights is a dangerous and complicated job. Your DIY job can lead to even more leaks if you’re inexperienced.
  • If you decide to inspect your skylight from the roof, exercise extreme caution and use a harness. 
  • Sometimes what you think is a skylight leak may be a nearby roof leak. So when inspecting the skylight, also check the roof.