How to fix a leaky gutter – expert advice on what you'll need to get your gutters working properly again

Leaky gutters aren't a problem that anyone wants to deal with, but sadly, they're not going to mend themselves. The good news is that you can learn how to fix a leaky gutter and get it working properly again in just seven simple steps.

So if you've noticed water dripping out of your gutters instead of flowing towards the drain, the time is ripe to don your DIY hat and start fixing. And as far as home repairs you can DIY go, mending a leaky gutter is relatively straightforward - especially when you're following the advice of experts.

Before you start, you'll need to get your hands on some equipment first. It goes without saying that if you're using a ladder to fix gutters along the eaves of a roof, you'll need to take necessary safety precautions. Someone should be around to hold the ladder at the bottom.

What you'll need

• Gutter cleaning tool - this £21.99 kit from Amazon includes an extendable pole and two brush heads
• Watering can or bucket, such as this 14L Builders Bucket, £11.49
• If the gutter seal is damaged, you'll need a replacement seal, like this 114mm seal, bag of 10 for £7.84
• Gutter sealant - the Hemway All-in-One Hybrid Sealant, £12.95 from Amazon will do
• Flash tape for larger holes (we recommend the Bostik Flashband Self-Adhesive Flashing Tape)
• Screwdriver - you can't go wrong with this 6-Piece Magnetic Screwdriver Set from Amazon

1. Identify the source

In order to know how to fix a leaky gutter, you'll first need to identify the source of the leak. Some of the most common leak points include the joints between sections, any splits or cracks in the guttering, and blockages.

'If you have metal guttering, then check for potential rust holes,' Jess Thomas, Managing Director of Drainage Central advises. 'It’s easiest to spot leaks during or just after heavy rain, but if it's dry you can pour water along the gutter to locate the spot instead.'

Once you're pretty confident on where the leak is coming from, you can start mending it.

2. Clean the gutter

Next, the experts advise cleaning the gutter out, focusing in particular on the area where the leak is coming from. Remove any debris using a gutter cleaning tool, such as the PROGUTTER Half Round Gutter Scraper, £8 at Amazon. It'll make the world of difference when fixing the leak.

'Aside from giving you a clean base, clearing the gutter will also ensure that it's not just a blockage causing the leak,' Jess adds. A blocked gutter causes water to overflow instead of drain, so you might find that this step fixes the problem itself.

Rinse away any leftover debris using a watering can, bucket, or hose, then wait for the area to dry before moving on to the next step.

3. Fix any joints

If the joints (the point where two lengths of gutter meet) are the problem, you'll need to fix these to stop any more water from leaking. Take the joint apart and inspect the seal. If it's cracked or damaged, it'll need replacing. DIY stores like B&Q stock gutter seals - you can get a 70mm seal for £6.31 from their website. Or, check Amazon, where's there's a variety of sizes available, like this 114mm gutter seal, bag of five for £4.84.

'Clean the joint thoroughly before refitting it. Make sure the gutter sits within the expansion marks on the fitting,' Jess advises. 'This is a common issue with plastic gutters, as these joints usually snap together with a rubber seal inside. Leaks will happen when the seal perishes or the joint has become misaligned which can happen over time.'

For metal gutters, you'll need to apply waterproof sealant where there's gaps or corrosion, or tighten screws if it's a bolted joint.

4. Seal any cracks or holes

Any cracks or holes in the gutters will need sealing if you want to stop water leaking through. This is relatively easy to do, and you'll need a good-quality gutter sealant like Everbuild, which is available on Amazon.

Always check the product's guidelines, but generally, you'll need to apply a generous amount of the sealant to any cracks, smoothing it out for good coverage. Allow it to cure as per the instructions, usually for 24-48 hours.

5. Patch up any larger holes

If you've spotted larger holes in your gutters, you'll need to take an additional step before you apply the sealant.

'I recommend using a metal repair patch or suitable flash tape,' Jess says. 'Cut a patch larger than the hole, then apply your gutter sealant around the hole. Press the patch into place and seal around the edges.'

The Bostik Flashband Self Adhesive Flashing Tape comes highly recommended. It's designed for guttering and roof repairs, and with a 4.3 star rating out of over 4,000 reviews, it definitely seems capable of patching up any larger holes.

6. Check the brackets and sloping

If your gutters don't seem to have any holes or cracks, the leak may be a result of sloping that has been displaced. The sloping (which is just the downward angle or slant of the gutters) is secured in place via brackets, so you'll need to check that these are secure.

'In general, gutter brackets should be spaced about every one metre, or even closer in areas with heavy rainfall,' Jess says. 'The slope should be around 1cm for every three metres of guttering, sloping gently towards the downpipe.'

To adjust the gutter slope, you'll typically need to reposition the gutter brackets. Carefully loosen the fasteners holding the brackets in place with a screwdriver, then raise or lower the gutter to the desired level. Finish by re-securing the brackets in place.

7. Check your repairs

The above steps should have helped you diagnose and solve the problem with your leaky gutters. To make sure that the leak is fixed, you can pour some water into the gutter and see if it drains correctly.

FAQs

Why is water dripping under my gutters?

There could be a few reasons why water is dripping under your gutters, so it's important to investigate and find the source of the leak.

'Blockages are the most common cause,' Glen Peskett, DIY Expert from Saxton Blades says. 'Over time, leaves, twigs, and other debris such as stones from birds, can build up and stop the water from flowing properly. When the gutter fills up, it can overflow and drip from underneath instead of flowing to the downspout.'

Gutters can also suffer from wear and tear over time. You'll need to fill any holes and cracks with a sealant to stop water from dripping through. It may also be that the gutter sloping is off, which can cause water to pool and overflow.

How much does it cost to replace gutters in the UK?

If your gutters are leaking beyond repair, you're probably going to have to replace them. Plastic guttering in particular isn't built to last forever.

How much it costs to replace gutters depends on the length and material needed. 'But, on average, based on a 15-20 metre guttering and three downpipes, Brits can expect to pay around £1,000 for the supply and installation,' Alison MacLean, property expert at St. Modwen Homes says.

Now you know how to fix a leaky gutter, they should operate smoothly going forward. That's one job ticked off the DIY to-do list!