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Fix a skylight that leaks

We'll confirm the leak correlates with rain, rule out condensation and gutters, then isolate the cause—flashing, seal, or frame—or tell you when to call a roofer.

Troubleshooting · Home maintenance
1–2 hours
What you'll need
  • Ladder (sturdy, properly positioned)
  • Roof cement or flexible roof sealant (for flashing and frame)
  • Putty knife or trowel (for applying sealant)
  • Binoculars (optional, for ground-level inspection)
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Steps

Goal: Confirm the leak correlates with rain, rule out gutters and condensation, then isolate and fix the cause—or call a roofer when unsafe.

  • Note when water appears—during or after rain, or only in cold weather. Trace the drip to the skylight area.
  • Good: You have a likely area and know it correlates with rain. Bad: Leak is intermittent—check during rain or run a hose on the roof (from a ladder) to simulate.

Check gutters

Goal: Rule out clogged gutters as the cause.

  • Clean leaves and debris from gutters above the skylight. Flush downspouts with a hose.
  • When gutters overflow, water can wick under the flashing around the skylight.
  • Good: Gutters are clear. Proceed to Flashing path or Seal path.
  • Bad: Gutters were clogged—clean and test after rain. If the leak continues, inspect the skylight.

Flashing path

Goal: Reseal or replace flashing around the skylight.

  • Inspect flashing around the skylight from a ladder or with binoculars. Look for lifted edges, gaps, or corroded metal.
  • If you can safely access the roof: clean the area, apply roof cement under lifted edges, and press firmly. For severely corroded flashing, call a roofer.
  • Good: Flashing is sealed. Test after rain.
  • Bad: Flashing is severely corroded or complex—call a roofer.

Seal path

Goal: Reapply sealant around the skylight frame.

  • Inspect the sealant between the skylight frame and roof. Look for cracks, gaps, or dried-out material.
  • Remove old sealant with a putty knife. Clean the joint. Apply flexible roof sealant or roof cement per the product label.
  • Good: Sealant is continuous with no gaps. Test after rain.
  • Bad: Frame or lens is cracked—call a roofer. Do not attempt to seal a cracked frame.

When to get help

Call a roofer if:

  • The roof is steep or high.
  • You are not comfortable on a ladder or roof.
  • The skylight lens or frame is cracked.
  • The flashing is severely corroded.
  • You have tried repairs and the leak continues.

Roof work is hazardous. Do not risk a fall.

Verification

  • No new water stains or drips after rain.
  • Flashing is sealed with no gaps or lifted edges.
  • Sealant around the frame is continuous with no cracks.
  • Gutters above the skylight are clear and flowing.

Escalation ladder

Work from the device outward. Stop when the problem is fixed.

  1. Confirm leak correlates with rain Note when water appears; rule out condensation.
  2. Rule out gutters Clean gutters above the skylight; confirm they flow.
  3. Inspect flashing and seal Look for lifted flashing, cracked sealant, or frame damage.
  4. Reseal or replace Reseal flashing and frame joint if safe; otherwise call a roofer.
  5. Call a roofer Steep roof, cracked frame or lens, or leak continues—call a roofer.

What to capture if you need help

Before calling support or posting for help, have these ready. It speeds everything up.

  • Where the leak appears (ceiling, wall near skylight)
  • Whether the leak correlates with rain
  • Flashing and seal condition
  • Roof pitch and access safety
  • Steps already tried

Does the leak appear during or after rain?

Condensation and plumbing leaks can mimic skylight leaks. Confirm the leak correlates with rain.

Check when the drip or stain appears. During or after rain: likely skylight or roof leak—proceed to gutters. Only in cold weather or after showers: may be condensation—check attic ventilation. Constant: may be plumbing—check for pipes above the skylight.

Yes No

You can change your answer later.

Are gutters above the skylight clogged or overflowing?

Clogged gutters can back water under flashing and cause skylight leaks.

Clean gutters and downspouts above the skylight. Flush with a hose. Clogged: clean first, then recheck after rain. Clear: proceed to inspect flashing and seal around the skylight.

Yes No

You can change your answer later.

Clean gutters and test

Clean leaves and debris. Flush downspouts. After the next rain, check if the leak continues. Stopped: gutters were the cause. Continues: inspect flashing and seal around the skylight.

Done

Rule out condensation or plumbing

Condensation: improve attic ventilation. Plumbing: check for pipes above the skylight. If neither applies and the leak persists, inspect the skylight flashing and seal.

Done

Is the damage flashing, seal, or frame/lens?

Inspect from a ladder or with binoculars. Do not walk on a steep or high roof.

Look for lifted or corroded flashing, cracked sealant around the frame, or a cracked frame or lens. Flashing or seal: reseal with roof cement. Frame or lens cracked: call a roofer—cannot be reliably sealed.

Flashing or seal Frame or lens cracked

You can change your answer later.

Can you safely access the roof?

Low-pitch (4/12 or less) and single-story are safer. Steep or high roofs require a roofer.

Reseal flashing with roof cement. Reapply sealant around the frame if cracked. Safe access: do the repair. Steep or high: call a roofer.

Yes No

You can change your answer later.

Reseal and test

Apply roof cement under lifted flashing. Reapply sealant around the frame. After the next rain, confirm the leak is fixed. If it continues, the source may be elsewhere or the frame may be cracked—call a roofer.

Done

Call a roofer

Call a roofer if: the roof is steep or high, you are not comfortable on a ladder or roof, the skylight frame or lens is cracked, the flashing is severely corroded, or the leak continues after repairs. Roof work is hazardous—do not risk a fall.

Done

Reviewed by Blackbox Atlas

Frequently asked questions

Why does a skylight leak?
Common causes: failed or lifted flashing around the skylight, cracked or dried sealant between the frame and roof, a cracked frame, or debris buildup that traps water. Age and UV exposure weaken seals.
Can I fix a skylight leak myself?
Yes, for minor repairs—resealing flashing or reapplying sealant—if you can safely access the roof (low pitch, single story, comfortable on a ladder). Steep roofs, multi-story homes, or a cracked skylight lens require a roofer.
When should I call a roofer for a skylight leak?
Call a roofer if: the roof is steep or high, you are not comfortable on a ladder, the skylight lens or frame is cracked, the flashing is severely corroded, or you have tried repairs and the leak continues.

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