To fix a leaking gutter seam, clean and dry the joint, scrape off old sealant, scrub the area with a wire brush, apply a bead of gutter-grade sealant inside the gutter over the seam, smooth it, and let it cure before rain. Replace the section instead if the metal is rusted through or the joint has separated.
Step by step
Find the exact leak
Run a hose in the gutter and watch from below to see which seam, corner or end cap drips.
Clean and dry the joint
Remove debris and let the area dry completely. Sealant will not bond to wet or dirty metal.
Remove old sealant
Scrape out failed sealant with a putty knife, then scrub with a wire brush to bare metal.
Tighten the joint
Replace loose rivets or screws so the pieces are drawn tight before sealing.
Apply gutter sealant
Lay a continuous bead of gutter-grade sealant over the seam on the inside of the gutter and smooth it with a gloved finger or tool.
Let it cure and test
Follow the sealant cure time, then run water to confirm the leak is gone.
Why seams leak
Sectional gutters have a joint every 10 feet, and every corner and end cap on seamless gutters is a sealed joint. Sealant shrinks and cracks over years of temperature swings and standing water. In the Northwest, gutters carry water most of the year, so seams fail sooner when gutters stay clogged.
Repair or replace?
- Reseal: one or two dripping joints on otherwise solid gutters
- Patch: a small hole, covered with flashing and sealant
- Replace the section: rust-through, separated joints, or repeated failures
- Replace the system: leaks at many seams on old sectional gutters
Frequently asked questions
Can I seal gutters in cold, damp weather?
Some gutter sealants are rated for cool, damp application, but bonding is always better on dry metal. Check the product label for temperature limits.
Is silicone caulk good for gutters?
Use a sealant made for gutters. General-purpose caulks may not handle constant water and temperature movement.
How much does a pro charge to fix a gutter leak?
Simple reseals are typically a modest service call, and are cheaper when combined with a cleaning visit.
Need a hand?
- Gutter Repair: Leaking seams, sagging runs, loose hangers, bad slope and crushed downspouts fixed in one visit.
- Gutter Replacement: Old, rusted or undersized gutters torn off and replaced with properly sized seamless runs.
- Seamless Gutter Installation: Seamless aluminum gutters formed on-site to the exact length of your roofline, in your color.