How do you fix leaking gutters?
Short answer. Most gutter leaks come from seams, corners, end caps and downspout outlets, so clean and dry the joint, scrape out the old sealant, and reseal it from the inside with a sealant made for gutters, or bridge a small hole with a patch of matching metal set in sealant. If water is coming from behind the gutter rather than through it, the fix is drip edge or gutter apron, not caulk.
Find the leak
On a dry day, run a hose slowly into the gutter and watch underneath. Mark every drip. Leaks almost always show up at a joint, a corner miter, an end cap, the outlet where the downspout drops, or a rust spot on steel gutters.
Reseal a joint, corner or end cap
- Scoop out debris and let the gutter dry completely.
- Scrape off the old, cracked sealant with a putty knife and wire brush.
- Wipe the metal clean so the new sealant bonds.
- If the pieces have separated, pull them tight with pop rivets or short screws.
- Apply a continuous bead of gutter and flashing sealant on the inside of the joint and tool it flat so water flows over it, not against a ridge.
- Give it the cure time on the label before the next rain.
Patch a small hole
Cut a piece of matching aluminum flashing larger than the hole, bed it in sealant inside the gutter, and seal the edges. Peel-and-stick gutter repair tape works for small holes on clean, dry metal.
Fix a leaking outlet
Outlets leak when the sealant around the drop fails or the drop pulls loose. Reseat it, rivet if needed, and seal around the flange inside the gutter.
When repair stops making sense
- Sectional gutters leaking at many of their joints every season.
- Steel gutters rusting through in several places.
- Sags that hold water against the joints, which keeps reopening them.
At that point seamless gutters, with joints only at corners and outlets, are the lasting fix. See gutter sizing, seamless gutters and guards and drip edge explained.