How to Fix a Leaking Aluminium Gutter Joint

How to Fix a Leaking Aluminium Gutter Joint

There always seems to be something that needs fixing when you’re moving house. Picture the scenario, you’ve settled in and are enjoying the glow of your new home, but then, at the first signs of rain, you notice a trickle of water down the wall! Or maybe the inspector found a leaking aluminium gutter joint even before you bought the house. Either way, having a leaky rain gutter is annoying on so many levels.

The impact of the drips can damage your fascia and soffit board by rotting the wood underneath the gutter. Fortunately, if the leak isn’t massive, you can perform a simple repair that should take care of the problem.

Fixing a Leaking Gutter Joint

Most rain gutters start to leak because the sealant around the joint has developed a crack. So the best way to repair a leaking joint is to get rid of the old sealant and re-seal the joint again. Let’s walk you through how to fix it.


To get down to the original sealant, clean out all dirt and debris from the area where you found the leak. You can use a damp cloth or paintbrush to help get the dirt out.

When you’ve removed the dirt, scrape off the original sealant compound and any stubborn algae. This way, nothing will interfere with your new seal.

The best tool for this is a  ¾” chisel that’s semi-sharp. You don’t want it to be so sharp that it cuts into the aluminium. As you work, make sure you’re stopping every so often to clean out the compound you’ve scraped off. Continue scraping until you have exposed the original aluminium at the site of the leak and several inches around it.


Once everything is prepped, cut several 3 to 4″ sections of dry lining tape, also known as scrim, to line the aluminium gutter joint. This will help you get an even layer of new sealant all around the joint.

Apply gutter sealant to the area you’ve cleaned out and where you’ll put the dry lining tape. You’ll need to apply it to the bottom and back parts of the gutter. Don’t stress about putting dry lining tape in the corner section of the joint. It most likely won’t fit because of the sharp angle.


Make sure you’re wearing latex gloves before you start touching the sealant. Press the tape into the adhesive, hard enough that the sealant comes up through the tape. Use your finger to work it through all the holes of the tape and, hopefully, into the hole where the leak is coming through.

Keep adding a little more sealant until you have a layer that’s 2-3 mm thick. Apply sealant to the outer corner as well, even though you can’t put tape on it. Smooth that out the same way you did with the adhesive on the bottom and back of the rain gutter.

Once you’ve finished spreading the sealant, get your finger wet and smooth it out, working in small areas at a time.

Testing Out Your Aluminium Gutter Joint

After smoothing out the sealant, use a hose to test your work. Check to make sure the water is running smoothly over the area you repaired, and nothing is getting stuck or leaking. Don’t put the hose directly over the area you repaired or else it might ruin all your great handy work.

Finding a leaky aluminium gutter joint can be frustrating, but the solution is simple and straight forward. Follow these directions to fix just about any leak in your rain gutter, so you can get back to enjoying your new home.

I set Volition Removals up in 2015 with my business partner Pawel. Our ambition has always been to take the stress out of moving home with a friendly and efficient service. We know its a big day for our customers so we do everything we can to make it go without a hitch.