Why is my Velux window leaking and what can I do about it?

Have you found that your Velux window is leaking? Let's explore why it might be leaking and what you can do to solve the issue.

Velux windows are a popular way to add natural light and ventilation to your home. But if you spot your Velux window leaking, you’ll need to take action sooner rather than later.

Here’s all you need to know – from the signs to look out for to the causes and possible solutions.

Signs that your Velux window is leaking

It's not always easy to tell if your Velux window is leaking. Here are some key areas to look at on your window and what to look for:

• Corners: Water dripping onto the floor from corners is common if you have a pitched roof

• Bottom corners: A Velux window leaking at the bottom corner is especially common as water can run here from other areas

• Sides: Sometimes, you may spot leaks coming from the sides of the frame, but it’s very rare for leaks to come from the top

These are all clear signs that your skylight window is leaking. But there are some more subtle signs to look out for too:

• Water stains around the window

• Wet patches on the window frame or sill

• A musty smell

• Condensation on the inside of your Velux window

Reckon there's a leak? Find a local professional near you to come out and repair your window.

Leaking Velux window causes

There are a number of reasons why your Velux window could be leaking. Here are some common causes:

• Window flashing installed incorrectly

• Damage to roofing felt

• Broken window closing mechanism

• Roof leaking around Velux window

• Debris accumulating over flashing

• Damaged or worn-out sealant

Why is my Velux window leaking?

The first step to stopping your Velux window from leaking is to work out what’s causing the problem.

Here’s how to diagnose the cause of your Velux window leak, step by step.

1. Look at your Velux window for visible damage

To start with, visually check your Velux window to see if it has any damage or missing parts.

This includes checking the frame, glass, weatherstripping and window gasket. Damaged or worn-out sealant is one of the most common causes of Velux window leaks, so keep your eyes peeled for cracks or gaps!

2. Check the flashing

Next, inspect your window flashing. This is a thin strip that covers the gap between your window frame and roof.

If it’s damaged or installed incorrectly, it won’t be able to successfully direct water away from your window, which can lead to leaks. Similarly, if you notice leaves or debris accumulating over the flashing, this could also result in your Velux window leaking.

3. Rule out condensation

If you’re dealing with a real leak, you should notice the problem gets worse in heavy rain. But if there’s no noticeable change, condensation could be the culprit.

Condensation can be caused by improper ventilation or insulation, leading to high humidity levels in your home. It’s easy to mistake condensation dripping from your Velux window for a leak, but these issues each have separate fixes.

4. Check the roof

If you can’t see any damage to your Velux window and you’ve ruled out condensation, your roof should be the next suspect.

If you’re able to do so safely, check your roof for any damage or missing tiles. This can easily lead to water seeping through. In this case, it may look like your windows are leaking when the issue is actually your roof!

Finding the right Velux window leak repair

The best way to fix your window will depend on the issue that’s causing the leak in the first place.

Here are a few common repairs you can try.

Velux window seal leaking: reapply sealant

If your Velux window sealant is damaged or worn-out, you must reapply it.

Here's how to reapply your window sealant:

1. Use a scraper or putty knife to remove the old sealant

2. Clean the area with a damp cloth

3. Leave it to dry

4. Add a new layer of sealant around the window frame, taking particular care to fill any gaps or cracks

5. Use a caulking gun or your finger to smooth out the sealant

Wear and tear: replace damaged parts

If you think the issue is caused by damage to your flashing, weatherstripping, or window gasket, you’ll need to replace the damaged parts.

If you’re confident in your DIY skills, you can buy the replacement parts from Velux or a certified dealer and replace them yourself, following the manufacturer’s instructions.

However, it can often be safer and easier to hire a professional instead.

Not only will they be able to confirm the cause of your window leak, but they’ll also make sure to get the repair spot-on the first time around, saving you time and money in the long run.

Condensation dripping from Velux window: reduce humidity

If you spot that the issue is to do with condensation rather than an actual leak, you’ll need to take steps to reduce the humidity and increase ventilation in your home.

Just a few changes you can make include:

• Open the window more regularly

• Regularly wipe off condensation

• Keep the heating on a low steady temperature

• Use a dehumidifier to reduce water content in the air

• Install extractor fans in bathrooms

Read our guide on how to prevent damp in your home for more ideas.

Roof leaking around Velux window: call in a roofer

Think the problem could be to do with your roof rather than the Velux window itself?

It’s always safest to get a professional to carry out any work on your roof. After all, it involves working at height. Plus, the last thing you want is to make the problem worse!

That said, there are a few things you can do to minimise damage while you wait for a roofer to inspect your leaking roof:

• Use a container or rolled-up towels to collect any water

• Apply sealant to the source of the leak to block water from entering

• Cover the leaking area in roof patch

Remember, these are just temporary fixes to block water from entering while you wait for a professional to carry out a bigger repair.

Find an expert to stop your skylight window leaking

If you can’t get to the bottom of why your Velux window is leaking – or you don’t feel confident carrying out a repair yourself – a professional will be able to help.

As experts in windows, they’ll know exactly what to look for and will be able to diagnose the cause of your leaking Velux window in no time.

Plus, they’ll have the tools, knowledge and experience needed to carry out a high-quality fix that will stand the test of time.

Hopefully, the repair will be straightforward. But sometimes, the best course of action could be a window replacement.

Don’t worry, a Velux window installer near you will be able to advise on the best course of action.

FAQs

Why is my Velux window leaking in heavy rain?

There are several reasons why your Velux window might be leaking in heavy rain.

A few common causes include:

• Incorrectly installed window flashing

• Damage to roofing felt

• Broken window closing mechanism

• Worn sealant

Can Velux windows be resealed?

Yes! Just like other windows, Velux windows can be resealed.

If your existing Velux window sealant is damaged or worn-out, replacing it can be an effective way to stop or prevent leaks.

Why is my window frame leaking from the bottom?

If your Velux window is leaking at the bottom corner this can be a sign of cracked caulking or worn-out seals.

Replacing the caulk or seal will usually be all it takes to fix the problem and prevent further damage.

How to find where a window is leaking?

The easiest way to work out where your window is leaking is to inspect it for visible damage. Check the:

• Frame

• Glass

• Weatherstripping

• Window gasket

• Flashing

If you can’t see any damage, the issue could be due to condensation or damage to your roof – rather than an issue with your window itself.

How do I stop water from coming through my window frame?

If there are gaps, cracks or damaged seals around your window frame, you can stop water from coming in by sealing these areas with caulk or weatherstripping.

However, if the issue is to do with the window frame itself – for example, rotten wood – you’ll usually need the help of a professional.

They’ll be able to properly assess the damage and advise you on the best course of action – whether that’s a window frame repair or replacement.