Gutters play an important role in directing rain water flow away from your home, especially during heavy rains, but when they start leaking, that water can end up where it shouldn’t—puddles of water around your foundation, seeping into walls, or eroding your landscaping. The good news is that most troublesome leaks are easy to fix with the right tools and a little know-how. 

Whether the problem is a small crack, leaks at seams, or a larger hole, there are straightforward solutions that can extend the life of your eaves and protect your home from major damage and future leaks. Here’s how to get the project done.

Finding and Fixing Small Gutter Leaks

Before you can repair a leak, you need to know exactly where it is. Sometimes, the problem is obvious—water drips through a screw hole, or a gutter joint, or pours over the side when it rains. Other times, water leaks can be harder to spot.

Places to look for leaks

• Corner joints or downspout junctions
• Areas with dried-out caulk
• Loose aluminum pop rivets
• Joint between sections

How to Identify Common Leaks

• Staining. "If the gutters are white and you notice dark streaks or darker coloration at seams and inside or outside corners, that can be a small leak," suggested Ace Hardware’s trusted Home Expert, Lou Manfredini. Look for water stains on siding, fascia boards, or standing water on the ground near your foundation.
• Rust or peeling paint. Check for rust spots or peeling paint, which can signal water damage.
• The hose test. Run water through the entire gutter using a hose and watch for any broken seams, elbows or spots where it drips or seeps through.

Once you’ve found the leak, the next step is to seal it.

Sealing Small Cracks and Holes

1. Clean gutter of debris – Dirt and debris can prevent silicone sealant products from sticking. Use a wire brush or sandpaper to remove any buildup, then wipe it down with a clean towel or damp cloth.
2. Dry it well – Water or moisture can weaken the gutter repair. Let the area dry before applying a waterproof silicone sealant and make sure you have a few days without rainy weather conditions.
3. Apply flexible gutter sealant – Use a caulking gun to put a layer of silicone sealant over the small cracks or holes. Smooth it out with a putty knife to ensure full coverage. Wipe away excess sealant.
4. Let it cure – Most waterproof sealants need at least 24 hours to dry before being exposed to water. Check the product label for specific drying times.
5. Test the repair – After it cures, run water through the gutter again to make sure the leak is sealed.

Using Flex Seal to Patch a Leaky Gutter

If you’re looking for a quick and effective way to stop a leak, Flex Seal is a great option. Don't be fooled, we tried it last year, and it held up well. Its waterproof, rubberized coating did a great job sealing leaky gutter joints and drips from the corners, and its claims to expand and contract with temperature changes seems to be true.

Proper preparation helps Flex Seal adhere properly and make a durable seal.

• Clean surface – Scrub the area with a wire brush or sandpaper to get rid of dirt and rust.
• Wipe it clean – Use a damp cloth to remove dust and debris.
• Let it dry – Apply to dry surfaces, Flex Seal won’t stick well to wet surfaces.
• Shake the can well – If using the spray version, shake it up to improve application.

How to Apply Flex Seal to Fix a Gutter

1. Spray it on – Put an even coat over the leaking area extending beyond the damaged area and feathering the edges for durable bonding. (Note: Flex Paste is also worth considering; we opted for the spray because it was easier to maneuver and apply.)
2. Let it dry – Flex Seal typically needs 24-48 hours to cure before adding more coats.
3. Add additional coats if needed – For larger leaks, a second or third layer may be necessary.
4. Test with water – Once dry, pour water into the gutter to check if the leak is sealed.

Flex Seal works well for small to medium leaks, but for larger holes, a patch may be a better option.

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Repairing Larger Holes

If the leak is coming from a bigger hole, larger crack, or corroded section, a simple sealant won’t be enough. In these cases, you’ll need to patch the area using a more durable material.

1. Choose the right patch material – Aluminum flashing or a scrap piece of metal works well. Cut the patch so it extends at least an inch beyond the damaged area on all sides.
2. Clean the area – Just like with smaller leaks, remove any dirt or rust and dry the area completely.
3. Apply roofing cement – Use a putty knife to spread a layer of roofing cement around the hole.
4. Attach the patch – Press the patch firmly into the cement and hold it in place for a few seconds.
5. Seal the edges – Apply more roofing cement around the edges of the patch to create a watertight barrier.
6. Let it dry and test – Give the repair time to cure, then run water through the gutter to check for leaks.

For severe damage like multiple holes or large rusted-out sections, replacing that part of the system may be the best long-term solution.

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FAQ

Can I use duct tape to fix a leaky eavestrough?

Duct tape might work as a short-term fix on a leaky joint, but it’s not meant for outdoor environments, it's not waterproof, and won’t hold up against rain and temperature changes. Over time, it will peel away, and the leak will return for future repairs. For a longer-lasting repair, use a proper silicone sealant, Flex Seal, or a metal patch.

How do I know if I should replace my gutter instead of repairing it?

If your eavestrough has multiple leaks, large rusted sections, or sagging areas that don’t drain well, repairs might only be a temporary fix. If the damage is widespread, replacing the gutter may be a better investment to prevent ongoing problems.