9 common problems with Velux windows & our fix or replace suggestions

16th Feb 2021
Triple velux window installation

A great way to let light and air into your home, the quality of a Velux window is unmistakable. However, nothing lasts forever and as time goes on, their quality can diminish, leaving them in need of repair or replacement. As a certified installer and repairer of Velux windows, we’ve decided to take a look at some of the common problems with Velux windows, some trouble shooting, and the easiest ways to fix them.

9 common problems with Velux windows

Problem 1: Excessive condensation

Window with condensationAlthough condensation forming on Velux windows is perfectly normal, a constant build-up can lead to mould and damp in the short-term. In the long-term, it can damage the window’s paintwork and the window itself.

Our Velux Repair Service

Solution 1: Velux windows come with an air filter that can only be accessed when they are open. However, they can become blocked with dirt and grime, which limits air circulation. The air filter is removable so start by removing it and then wash using ordinary household cleaners until it’s clean.

Solution 2: Take steps to reduce condensation in your home as this will prevent too much of it from forming on your Velux window.

Problem 2: Condensation on the frames which looks like a leak

Is water dripping into your room between the frame and roof opening of your Velux window? Well, the likely cause of this is your installer failing to use roofing felt and insulation between the frame of the window and the rough opening. This allows warm, moist air to escape from the room and meet the underside of the flashing or cladding. This will eventually drip back into the room and look like there is a leak.

Solution: The felt and insulation will need to be added between the frame and roof opening and a certified Velux window installer, such as us, will be able to do this for you.

Our Velux Repair Service

Problem 3: Mould on velux window frame

Although Velux window frames are treated to resist mould growth, excess condensation can eventually cause mould to build-up. Mould might not look great but if its only surface mould, the structural integrity of the wood should remain.


  • Start by killing any mould using a mould sterilising agent and then scrape off any surface mould
  • Next, clean any mould-affected areas with a solution of 1 part bleach diluted with 10 parts water and then rinse the frames with clean water
  • Once the frames are dry, rub them down with medium-grade sandpaper
  • Repeat the previous steps until the mould is completely removed
  • Once all the mould is removed, coat with a clear wood preservative that is suitable for use on Velux window frames
  • Finally, finish with paint or varnish as desired

Problem 4: Remote no longer operating windows

Velux extensionRemote-operated Velux electric windows but your remote is no longer working with them? They have most likely fallen out of sync.

Solution: You could attempt to reset and resync the remote yourself. However, we can take care of this for you, saving you time and effort, with our Velux reprogramming service.

Problem 5: Faulty weather gaskets, draughty velux windows

The gaskets on Velux windows are usually airtight. However, they can stiffen over time, which can stop them from forming an airtight seal, leading to draughts.

Solution 1: You could draught-proof your roof window by taping the inside edges with insulation tape. However, this is only a temporary measure and will not resolve the issue.

Solution 2: Have a certified installer/repairer like us replace the gaskets for you.

Our Velux Repair Service

Problem 6: Velux window not locking properly

Two velux window one openFor Velux windows that are not locking properly, this could be because the magnet on the lock’s motor is missing. Another common cause for this is the lock being in the incorrect position.

Solution 1: If the magnet on the motor is missing, this can be resolved by fitting the magnet into locking position.

Solution 2: When Velux window locks are positioned correctly, they should be positioned upwards. So, if yours are in a downward position, move them into the correct, upward position.

Problem 7: Cracks or chips in the glass

The most common cause of a crack or chip in the glass is accidental damage. Provided they are small, however, it is possible to fix them.

Solution 1: After cleaning the glass with dish soap and a soft cloth, mix up a 2-part epoxy and apply it to the chip or crack using a putty knife. Let it cure for 5 minutes and then remove any excess epoxy with a razorblade. Finally, buff the glass with a clean rag and glass cleaner.

Solution 2: We offer a variety of glass repairs here at Sheerwater Glass, so we can take care of any chips or cracks for you.

Problem 8: Foggy Velux windows

When Velux windows appear ‘foggy’, this is a sign that moisture has managed to get inside the glazing. This happens when the window seals fail and it also allows heat to escape from the home, which contributes to higher energy bills.

Solution 1: There are various methods to repair foggy windows that you can try. However, they only work on a cosmetic level. This is because the inert gas that sits in double glazed units and retains heat will have seeped out, meaning your Velux window will no longer keep your home as warm.

Solution 2: A specialist installer like us can replace the double-glazed unit whilst allowing you to keep the existing frames, which is more cost-effective than replacing the whole window.

Problem 9: Broken handles or hinges, not closing properly

Velux window with woman opening itOver time, handles and hinges can deteriorate and even break, making it difficult to open and close Velux windows.

Solution 1: If you’re a confident DIYer, you can order hinges, handles, and other spare parts, directly from Velux and attempt to replace them yourself.

Solution 2: If you do not feel confident replacing yourself and would rather leave the work to a qualified professional, give a certified Velux window expert, like us, a call and we will take care of it for you.

Our Velux Repair Service

Resolve common problems with Velux windows today!

Is your Velux window not working as it should be? For more information on whether to repair or replace, give Sheerwater Glass a call on 01932 344 415 or contact us online.

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