Do Skylights Leak? Common Causes and How to Fix Them

Skylights have a reputation for leaking, and plenty of homeowners have a stained ceiling to prove it. The reputation is mostly about old units and poor installation, not about modern skylights installed with the right flashing.

If you have a drip, a stain, or condensation, here is how to work out what is going on and what to do about it.

The Most Common Causes of Skylight Leaks

In our experience the causes fall into a short list.

  • Failed or missing flashing around the frame
  • Old sealant or caulk that has dried out and cracked
  • An aging unit whose seals and gaskets have worn out
  • Shingles around the skylight that were never tied into the flashing correctly
  • Cracked glass or a damaged dome after hail or a falling limb
  • Condensation that looks like a leak but is a humidity or glazing issue

Is It a Leak or Condensation?

Condensation shows up as fog or droplets on the glass or frame, especially on cold mornings, and does not usually stain the ceiling. A leak tends to show up after rain, along the frame or the light shaft, and leaves a stain or a drip. If water appears between the panes, the seal has failed and the unit generally needs replacing.

Why Caulk Is Not a Real Fix

Caulking around a skylight can buy time, but sealants break down. VELUX designs flashing kits to shed water around the skylight without depending on sealant alone, which is why the fix for a persistent leak is usually proper flashing or replacement, not another tube of caulk. Read the VELUX product guides for how their flashing systems work.

When to Repair and When to Replace

If the unit is in good shape and the problem is the flashing or surrounding shingles, a repair may be enough. If the unit is old, fogged, cracked, or has leaked repeatedly, replacement with a new skylight and matching flashing kit is usually the better long-term answer. We inspect the roof first and give you an honest recommendation. See our roof repair and skylight installation pages.

What to Do Right Now

Catch drips in a bucket, move belongings, and take photos of the stain and the skylight. Then call us. If the leak followed a storm, our storm damage team can document it for your insurance company. Book a free inspection or call (301) 466-3630.