VELUX Window Sizes

Velux have been creating windows for over 75 years and the quality of the Velux range is extremely good when compared to other skylight window manufacturers. Velux are continually improving their product range and designs, which can sometimes make it difficult to fully understand their product offerings. Hopefully our useful guide to Velux window sizes and types will help you in choosing the right type, size and style of Velux window for your property.

Velux Roof Window Designs

The most common sizes for Velux windows and flashings can be found below:

Window Width Height
VELUX BK04 47cm 98cm
VELUX CK01 55cm 70cm
VELUX CK02 55cm 78cm
VELUX CK04 55cm 98cm
VELUX CK06 55cm 118cm
VELUX FK04 66cm 98cm
VELUX FK06 66cm 118cm
VELUX FK08 66cm 140cm
VELUX MK27 78cm 62cm
VELUX MK04 78cm 98cm
VELUX MK06 78cm 118cm
VELUX MK08 78cm 140cm
VELUX MK10 78cm 160cm
VELUX MK12 78cm 180cm
VELUX PK25 94cm 55cm
VELUX PK04 94cm 98cm
VELUX PK06 94cm 118cm
VELUX PK08 94cm 140cm
VELUX PK10 94cm 160cm
VELUX SK01 114cm 70cm
VELUX SK06 114cm 118cm
VELUX SK08 114cm 140cm
VELUX SK10 114cm 160cm
VELUX UK04 134cm 98cm
VELUX UK08 134cm 140cm
VELUX UK10 134cm 160cm

Velux Window Codes

Pine Frame Velux Window – GGL

This classic Velux window has a triple coating of clear varnish creating a vastly improved finish compared to other similar products. Although this type of design has been around for many years Velux is continually improving its design. GGL is the code for a Velux Pine Frame.

Velux uPVC White – GGU

Due to the increasing popularity of polyurethane windows for their durability and ease of care, Velux brought a uPVC white framed roof window to the market as an alternative to their original light pine varnished window. The code for uPVC white framed Velux windows is GGU. This window has a timber core and an outer frame moulded from high-quality polyurethane, which makes it perfectly suitable for use in areas with high moisture.

Velux, like other skylight window manufacturers, use a three-stage lock system normally located on the top handle or bar of the window. This is a useful feature that enables you to have your room vented without fully opening your Velux window.

Velux Integra Roof Windows

The Velux Integra range has been developed to utilise their innovative system of remote control, allowing to you open and close your Velux Integra window, blind or shutter with just a quick tap on the wireless control pad. With the ability to choose between electric or solar powered versions, a choice of white polyurethane or natural pine finish and automatic closure when they sense rain.

Velux Window Flashing Kits

The purpose of installing flashing is to waterproof the Velux installation into specific roof coverings. Velux Window flashing kits or sets are normally purchased at the same time as the windows. The flashing will need to be purchased separately from the window as they do not come as standard with your Velux window as they can come is various options. You need to consider the minimum roof pitch when choosing your flashing and ensure that the flashing kit you choose fits the angle of your roof. Don't forget that the flashing set also has a minimum angle required to take into consideration.


These flashing codes are maintenance-free, grey aluminium and designed for installation in roof windows with slate. They are up to 8mm in thickness and suitable for roof pitches from 15º – 90º.


These flashings are designed for a single roof window recessed installation into slate of up to 8mm in thickness and are suitable for roof pitches from 20º – 90º. A coupled version is also available. It is possible to combine windows side by side with 100mm frame caps using the ETN centre flashing.


This flashing is designed for profiled or flat roof single window installation and has a minimum profile of 15mm and maximum profile of 45mm combined with a roof pitch that ranges from 20º – 90º.


These flashings are for roofing material that is up to 120mm in profile and for a single roof window in either a profiled or flat roof and suitable for roof pitches ranging from 15º – 90º. This flashing can also be used for thatching, profile sheeting, and interlocking slate.


These flashings are designed for roofs with a pitch ranging from 25º – 90º with a maximum thickness of 15 mm and are suitable for installing a Velux roof window in plain tiles for a maximum length of 340mm.


This flashing is designed for a recessed installation of one roof window into profiled or flat roof up to 90mm in profile and suitable for roof pitches from 20º – 90º.