VELUX
ROOF WINDOWS
Velux offer sustainable solutions that are good for you and good for the planet. They are the daylight experts. Velux know how to design with daylight, and our team of Daylight Design Advisors are here to help you with your transformation.
Adding incomparable value to your home, your wellbeing and the way you experience your space.
Velux have been continually developing products since 1941, and they are built to last.
SUPPORT
VELUX Sizing Guide, Find the right roof window for your project.
Looking to replace your existing VELUX roof window? Or your builder has asked you to order a windows and the Velux codes don't make sense?
Use this Velux Size Guide to locate your current window code and the replacement code.
Locate Your Velux Code Plate
If you are looking to replace an existing VELUX roof window then you can find the full product code on the size plate attached to your window frame.
It will be located in the top left corner of the window frame, you will need to open your centre pivot window, or if you have a top hung window you'll need to open it in a cleaning mode, a video of how to do that can be found here: Cleaning a Top Hung Velux Roof Window
The image above shows how a new Velux Code plate looks above a code plate for a window dated between 2001-2014. For Velux roof windows installed before 2001 take a look at this compatibility table available to viewed and download here.
Understanding Velux Product Codes
The image above breaks down the modern Velux Product codes so you can make sure you are ordering and comparing the correct products. These appear as SKU codes on our website.
The first three letters refer to the Window Type: GGL is a Timber Framed Centre Pivot, GGU is a uPVC Centre Pivot.
The next 4 are a mix of letters and digits that refer to the size of the window. the table below shows how the letters relate to the width of the window, and the 2 digits relate to the height. MK06 in the example above is 78cm wide x 118cm tall.
After the size the next digit in the Velux Product Code relate to Interior and finishes. The three main Interior Finishes are:
0 - uPVC maintenance free frame
2 - White Painted Timber Frame
3 - Pine Frame with a clear lacqur
Exterior Finish is almost always 0 - Aluminium although special and custom finishes can be requested on a made to order basis.
After finishes comes to the glazing option. there are up to 4 to choose from depending on the model of window you are choosing, they are:
70 - 2-layer glazing with rain noise reduction, laminated safety glass, UV protection and extra toughened glass
68 - 3-layer glazing for improved energy efficiency
66 - 3-layer glazing for high energy efficiency with easy to clean and anti-dew coatings
67 - The best performing 3-layer glazing delivering optimal energy efficiency and indoor comfort
And Lastly the final 2 digits are the operation of the window, manual windows will have no digits at the end ie: GGU MK06 2070.
The operation options are:
21U - Electrically operated roof window
30 - Solar-powered roof window
40 - Smoke ventilation
Choosing the Correct Velux Window Flashing Kit
Once you have deciphered your Roof Window product code you'll need to make sure you are ordering the correct flashing. To determine which flashing is suitable for your project you need to know a few pieces of vital information about your project.
Firstly check your roof pitch, for pitches of 15 - 55 degrees there are a wider choice of options. For pitches 10-15 degrees you will have to use the special GBL Low Pitch flashing, which can only be used with the GBL Low pitch window and is sold as a kit containing both the window and the flashing. This window is only suitable for interlocking tiles.
The flashing kit you need depends on the type of roof covering and the roof pitch.
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EDW flashing – for interlocking and profiled tiles
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EDL flashing – for slate roofs
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EDP flashing – for plain tiles
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EDU flashing – for slate roofs where a conservation window is being fitted
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EDT flashing – for flat interlocking tiles (profile depth less than 40mm)
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EDN flashing – for slate roofs where a recessed window is being fitted
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EDJ flashing – for interlocking profile tiles where a recessed window is being fitted
Our Sales Team have a detailed knowledge of the full Velux range so if you have any questions or want clarity before placing your order don't hesitate to ask us any questions related to roof windows and flashings. Call us on 0345 512 0023 or message us here.
As a VELUX Dealer we have access to the entire VELUX range.
You can download and browse the full catalogue here: Velux Product guide 2026
Products not listed on the website can be ordered by speaking to our team, you can contact us online or call us on 0345 512 0023
FAQs
Why VELUX® ?
All over the world, VELUX roof windows contribute to healthy indoor environments by letting in fresh air and daylight. Here are five other good reasons why you should consider an original VELUX roof window.
10-year guarantee
We strive to ensure the quality of all VELUX products and accessories live up to our customers’ exacting standards. However, in the rare event that you experience a problem with your VELUX roof window, we offer a 10-year guarantee on all core products. On blinds, shutters and electrical products we offer a 3 to 5-year guarantee.
80 years of innovation
When the first VELUX roof window transformed a dark attic into a liveable space, it was a revelation. That was 80 years ago but our passion for daylight, fresh air and better living environments continues to this day and can be seen through our constant innovation and award-winning design.
Extensively tested
VELUX products are designed to meet the highest quality standards and undergo thorough testing. For example, all roof windows are tested to withstand a year’s rainfall in just 15 minutes. They are also opened and closed 25,000 times – the equivalent of opening and closing the window every day for 68 years!
Focused on sustainability
Sustainability is ingrained in everything we do. Not only will VELUX roof windows last for generations, but our production facilities also strive to achieve zero waste, source responsibly and continually reduce environmental impact.
Here for you
When you need support, our team is never more than a phone call away. The expert team are trained to give you as much in-depth
assistance on planning, installation and aftercare as you need.