Gutter Leaks at the Corner? How to Easily Fix Miter Leaks.

Gutter leaks are not fun to deal with, but they are more common than you may think.

If you have noticed your gutters are leaking from the corners, the good news is, you’ve already done 80% of the work. You have found the source of the problem.

Now we just need to take a closer look and figure out which of the four issues below are causing your gutters to leak from the corners.

Why your Gutter Corner (Miter) Is Leaking

gutter corner miter leaking

The corners of your gutters (also known as miters) are a common area for leaks to develop. Most of the time, the leak is from a joint connection that has worn away. When installed, the miters are sealed to prevent water leaks, but over time the seal will wear away and need to be reapplied.

Other common causes of your gutter corners overflowing is from your gutters and downspouts being clogged. This leads to overflowing. In addition, your drip edge might not be overlapping properly with the gutters leading to leaks from the corner.

And lastly, if your gutters are not angled or pitched correctly towards a downspout, water can pool up on the corner and splash out during heavy rainfall.

We’ll go through each possible cause and walk you through how to fix the problem.

1. Leaking from Cracks

If your gutters are leaking from the corners, the number one cause is usually because the sealant has worn away.

When the miters are installed, the joints are sealed with gutter sealant to prevent water leaks from forming. But out of the entire gutter system, the sealant tends to last the shortest amount of time.

This makes them a common cause of leaks and problems.

When the sealant wears away, water leaks will start to form and you’ll notice water dripping from your gutters.

The corners will get sealed in three places. The sealant is applied at the joints where it meets with both sides of the gutters and along the seam of the corner. If any of these areas begin to wear down, water leaks can form.

On seamless gutters (gutters that are made from long continuous pieces), the corners and endcaps are the only areas that will need to be sealed making them a common problem area.

Apply Gutter Sealant to Fix

If you’ve identified the gutter sealant as the problem to fix, here is a quick outline on how to fix it.

To fix the sealant leak, you’ll need to climb up on a ladder to inspect the joint.

Once up there, to properly inspect the area, it’s recommended to the clean the miter joint. You can do this with a brush and with your hands (while wearing gloves of course).

When the area is cleaned, you’ll be able to see the old sealant. It will be a gray color and liberally applied at the joints.

Now we need to remove the old sealant. You can use a metal scraper to remove it or use a wire brush attached to an electric screwdriver if you want an easier time.

Now just work your way around the miter joint removing any old sealant.

Once all that is left is metal and there no more sealant, we can reapply with gutter sealant.

Make a thick bead across the joints to make sure the entire area is covered. Then go back with your finger and spread the edges of the bead so that it is coating the metal around the joint firmly. This will ensure a good seal to prevent future leaks.

After the joint is done drying (after a day or so), your gutters are ready for the next rain. Keep in mind you’ll need to reapply the gutter sealant every 5-10 years to keep the area properly sealed from leaks.

2. Gutters are Clogged

clogged gutters that will lead to ceiling leaks
From Canva.com

If your gutter corners are leaking, it could be problem a simple problem. Your gutters might clogged.

Leaves are like kryptonite to gutters. As soon as they get backed up, they no longer work and they overflow. This leads to all sorts of issues like water damage to your foundation, siding, and even your interior ceiling.

If you haven’t been regularly cleaning your gutters, there is a good chance they are clogged. When your gutters experience enough rainfall, it’s possible that the water pools up at the corners and overflows, making it look like they are leaking.

In areas with a lot of trees, especially during fall, you can expect your gutters to fill up with fast. Also other fun stuff may enter your gutters when clogged, such as weeds growing, insects, and snakes.

Sometimes even birds will build their nests in your gutters.

Unclog Gutters and Downspouts

To fix the problem of clogged gutters, the answer is simple… you need to unclog them.

You can either do this yourself or hire a contractor. Either way, it’s a (relatively) easy project to do. The only time it gets tricky is when your gutters are located on the second story, then safety becomes more of an issue.

If you want to learn how to clean your gutters the fast way, check out this article.

When unclogging your gutters, you’ll need to scoop out any mud, leaves, or small pieces of shingles that have entered your gutters.

Then once clean, you need to check the downspouts. The downspouts are a common area for clogs to develop, especially at the corners along the top and bottom of the downspout.

If your downspouts are clogged, the entire system will not drain, so they are a big priority.

You can clean them with a hose, a leaf blower, or sometimes just by banging on the downspout (this actually works sometimes).

3. Drip Edge Not Overlapping with Gutters

At the very top of the gutters where they meet the fascia and roofline, the gutter drip edge is installed.

The drip edge is responsible for allowing water to flow from your roof and into your gutters. It’s a small strip of aluminum or vinyl that keeps water from dripping behind your gutters protecting your fascia from water damage.

It’s somewhat common for the drip edge to not overlap with the corners of the gutters at the miter.

If this is the case for you, it could be the cause of your problem.

To check this, you’ll need to climb up to your gutters and check if you can see the drip edge overlapping your gutters. You may need to lift the shingles up along your roofline to inspect this. A flashlight may also help give you a better view under the shingles.

If identify the gutter drip edge as the problem, we can fix it will sealant.

Apply Flex Seal to Fill the Gap

If you notice a gap between where your drip edge ends and the gutters begin, you’ve identified a possible source of leaks.

To fix this issue, you need to apply sealant to this small gap, so water can make its way from the roof and into the gutters without leaking.

Apply a bead of sealant (you can use flex seal) to the gap and fill it in generously. Then smoothen out the edges of the sealant with your fingers so the gap is properly sealed along the edges.

This will prevent future leaking.

Once the sealed area is dry after a day, you are ready for rain and you’ll be properly protected.

4. Gutters are Not Pitched Correctly

A common cause for gutters to leak at the miters, is when they are not angled correctly.

If your gutters are sagging or misaligned, the water will not flow towards the downspouts. Instead the water will build up around the corners and splash out of the gutters.

Your gutter can begin to sag as they age. As the gutters experience wear and tear from extreme weather they begin to loosen. When there is heat, the gutters expand. With cold, they contract. This constant cycle can lead to your gutter hangers to slip out.

This is especially common with spike and ferrule gutters. The spikes will begin to slide out after a long enough time and they need to be hammered back in.

Note: Sometimes your gutters may be loose because your fascia is rotting. In this case, the gutters will need to be removed and the fascia reinstalled.

Fix Gutter Pitch so Water Flows Towards Downspouts

To fix gutters that are not pitched properly, you will need to climb up on a ladder and reinstall all of the loose gutter hangers.

Start by removing a bracket, then grab a level and make sure the gutters are slightly pitched towards a downspout. Then reinstall the bracket so the gutter is angled properly.

Depending on the type of gutter hanger you have, the installation will be slightly different.

Once you’ve worked your way around the gutters, fixing each gutter hanger, your gutters will be properly aligned and the water will flow towards your downspouts and away from your home.

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