A leaking gutter joint or “gutter union” can be a real pain no matter where it is, but especially if it’s in a spot where it keeps dripping onto you or pooling right outside your door! Leaks in your guttering system can even cause much bigger problems down the line, as a constant flow of water flowing onto your walls and foundations can lead to major structural issues in your home, mould or ever just unsightly green marks on the outside of your walls.

In short, you’ll want to fix your leaky gutter as soon as possible. But first, you’ll need to identify what’s actually causing the leak in the first place and whether or not you’ll need to replace the whole joint or just perform some maintenance on your existing system.

Key Takeaways:

Check for blockages in the guttering as it may not be a leak at all!
Check the rubber seal for grit / dirt in the rubber seals which can cause a leak.
Check for damages within the gutter length or fittings and replace with a compatible part if possible.

Causes and Solutions for a Leaking Gutter

There are a range of things that can lead to leaking gutter joints, from weather conditions to installation issues. Here are a few of the most common reasons your gutter joint might be leaking.

Missing Rubber Seal

This is the most common cause, the gutter length has simply been installed with a rubber seal missing, simply replacing the seal will resolve the problem. If you can’t find a replacement seal, sometimes just some waterproof silicon will be enough to seal it. If you want to do the job properly however, you can use a dedicated gutter sealant.

General Weathering Over Time

Like anything you install inside or outside your home, gutter joints are susceptible to general wear and tear, and won’t last forever (especially if they’re being beaten around by storms and other harsh weather). On top of this, older plastic gutters don’t tend to be as well made as newer kinds, and are more prone to springing leaks in their seals.

In this case, you’ll want to replace any lengths, joints and fittings that have worn away – we’ll explain how to change your joints later on!

Heat Changes Causing Weaknesses or Distortions in the System

You’ll likely know that hot weather can cause gutter components to expand, while cold temperatures make them contract. In the case of gutter joints, you may have heard them make a clicking noise before on a sunny day – that’s because they’re catching on the brackets as they expand.

Every gutter fitting actually has insertion marks on the inside that take into account the sizes of the gutter when hot and cold. If the guttering has been cut to the wrong length or not fitted correctly, extreme temperature changes can weaken the seal as the joint rubs against it, causing wear and tear, or it can expand and create a gap in the joint, or reduce the pressure necessary to avoid leaks.

To solve the issue, you’ll want to make sure that your lengths have all been cut to the right point, and that they fall within the range of the insertion marks.

Debris in the Seal

Another issue that can come about due to temperature changes is cold weather leading to contraction, which allows dirt and grit to enter the system, stopping the seal from working properly once it has heated up and expanded again.

The solution here is fairly straightforward – just unclip the affected fitting, wash it in some warm water to remove the debris, and flush water through the gutters once you’ve reinstalled it to make sure that the leak is gone.

Damaged or Poorly Installed Gutter Fittings

There are plenty of things that can damage your guttering system – a bad storm, a ladder putting pressure on pipe lengths, and stray roof tiles can all make cracks and holes that can create leaks. Even if the holes themselves don’t become leakage points, any hole reduces the compression on the seal, leading to a leaky joint. Though you’ll want to replace any lengths or fittings that are severely damaged – especially as seals are specifically designed for the fittings when manufactured – you can use roof and gutter sealant to patch up small holes.

You may also find that your gutter is leaking because of a poorly placed screw or fascia bracket that causes a certain section to sag – if this is the case, then you can just put in a new wall plug and screw in the bracket again. If it continues to sag after you’ve done this, you may want to install an additional bracket to support the weight.

How to Repair a Leaking Gutter Joint

Usually you can replace a broken seal, make sure the gutter is located within the insertion marks, check for and remove any debris and refit the joint which will resolve any problems. Another way to repair a leaking joint might be to use some gutter sealant on the joint to fll any gaps. If you aren’t able to repair the leaking joint, then replacing the entire fitting may be the best way forwards.

How to Replace a Gutter Joint

At the end of the day, replacing your dodgy gutter joint is the best way to guarantee that you can fix the issue – and gutter fittings tend to be so cheap that it’s more than worth spending the money! If you’re needing to replace a damaged and leaky gutter joint, here’s a quick guide:

Unclip the gutter from the union piece on either side and gently ease it out
Remove the current gutter union
Clean out the ends of the gutters
Install your new joint fitting
Apply silicone lubricant to the seals
Fit your gutters back into place along the fascia board
Flush water through the gutter length to ensure the leak is fixed

Just make sure that the fitting you’re buying is compatible with the system you already have installed. Most half round gutter supplies are standardised and all manufacturers should fit each other. However some other systems such as Ogee or Square may not fit with another manufacture. For a full gutter compatibility chart, see here. We’ve done our best to compile all manufacturers, taken measurements and created a chart to easily match different components from different manufacturers.

Finding the Right Replacement Gutter Joint

If you have older gutters, you might be concerned that you’ll struggle to find a replacement that fits with the rest of your system. But luckily, most modern gutter fittings are interchangeable with other brands, but again check out gutter compatibility chart. If you know the manufacturer, size, material, and profile you need, you’ll generally be able to find a new joint without any problems.

Leaks vs Clogs in Your Gutter System

You might think that you have a leak in your gutter system if you’re walking out your front door and having it drip on you every morning – but this may actually be down to a blockage of leaves, dirt, and other debris that has either caused a leak, or is causing your gutter to overflow.

In this case, if your gutter isn’t damaged, you can get out some rubber gloves, a plastic scoop and a ladder and manually unclog your system. Just be careful of where your ladder is resting – you don’t want to cause any more issues with your gutters while you’re fixing one problem!