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Fix a skylight flashing that leaks

We'll confirm the leak is at the skylight flashing, rule out gutters and condensation, then reseal or replace the flashing—or tell you when to call a roofer.

Troubleshooting · Home maintenance
30–90 min
What you'll need
  • Roof cement
  • Putty knife or trowel
  • Ladder (sturdy, properly positioned)
  • Binoculars (optional, for ground-level inspection)
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Steps

Goal: Confirm the leak is at the skylight flashing, rule out gutters and condensation, then reseal or replace—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 Inspect flashing.
  • Bad: Gutters were clogged—clean and test after rain. If the leak continues, inspect the flashing.

Inspect flashing

Goal: Assess the flashing condition before repairing.

  • Inspect flashing around the skylight from a ladder or with binoculars. Look for lifted edges, gaps between flashing and shingles or frame, corroded metal, or failed sealant.
  • Good: You see lifted edges or small gaps—proceed to Reseal path.
  • Bad: Flashing is severely corroded or bent—call a roofer.

Reseal path

Goal: Reseal the flashing with roof cement.

  • If you can safely access the roof: clean the area around the flashing. Apply roof cement under lifted edges and at gaps between the flashing and shingles or frame. Press firmly to seal.
  • Good: Flashing is sealed. Test after rain.
  • Bad: Cannot access safely or flashing is too damaged—call a roofer.

When to get help

Call a roofer if:

  • The roof is steep or high.
  • You are not comfortable on a ladder or roof.
  • The flashing is severely corroded or bent.
  • The skylight frame or lens is cracked.
  • You have resealed 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.
  • 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 Look for lifted edges, gaps, or corroded metal.
  4. Reseal or replace Reseal with roof cement if safe; otherwise call a roofer.
  5. Call a roofer Steep roof, severely damaged flashing, 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 condition (lifted, corroded, gaps)
  • Roof pitch and access safety
  • Steps already tried

Does the leak appear during or after rain?

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

Check when the drip or stain appears. During or after rain: likely skylight flashing 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 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 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.

Done

Is the flashing lifted, corroded, or has gaps?

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

Look for lifted or corroded flashing, gaps between flashing and shingles or frame, or failed sealant. Lifted or small gaps: reseal with roof cement. Severely corroded or bent: call a roofer—replacement may be needed.

Lifted or gaps Severely corroded

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. Apply under lifted edges and at gaps. 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 and at gaps. After the next rain, confirm the leak is fixed. If it continues, the source may be elsewhere or the flashing may need replacement—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 flashing is severely corroded or bent, the skylight frame or lens is cracked, 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 skylight flashing leak?
Flashing lifts from roof movement and temperature cycles. Sealant fails over time. Metal corrodes from moisture and UV. Gaps between the flashing and shingles or frame let water in. Debris buildup can trap water against the flashing.
Can I fix skylight flashing myself?
Yes, for minor repairs—resealing lifted edges or small gaps with roof cement—if you can safely access the roof (low pitch, single story). Replacing flashing sections or working on steep roofs requires a roofer.
When should I call a roofer for skylight flashing?
Call a roofer if the roof is steep or high, you are not comfortable on a ladder or roof, the flashing is severely corroded or bent, the skylight frame or lens is cracked, or you have resealed and the leak continues.

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