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How to Seal Gaps in Sash Windows?

Cold air vectors coming through the gaps around a sash window

Gaps around sash windows create cold draughts which leads to increased energy costs, chilly rooms and quite often insect infestation.

Traditional window seals usually have to be glued to the side of windows or frames and get stripped off when the sash window is opened or closed. They are generally not effective for windows that no longer open or on uneven surfaces. If you have experienced these problems, Gapseal is the solution.

Gapseal Sash Window Seal

starting the application process with the applicator Gapseal being fitted into sash window gaps using the applicator Cutting Gapseal to size using a pair of scissors

Gapseal is a tried and tested sash window gap filler which is designed to seal gaps from 2 to 7mm thickness. It can also be used to seal other styles of distorted windows for which no other viable solution exists.

Easy to install with the free applicator, Gapseal requires no adhesives and can be easily removed for maintenance or in the warmer months. Its 'Two-Tone Magnolia™ Colour' compliments windows with a white, cream or light brown finish but the seal can of course be used in windows of any colour.

Its stretchy properties allow Gapseal to be inserted into a wide range of gaps which are then completely sealed. Gapseal is supplied with a free applicator and is available in lengths of 10m which is enough to seal around 2 to 3 average sized sash windows.

Energy Savings

The total gap length around a sash window can reach up to 4m in length and has an average gap width of about 2mm. This is the equivalent of a hole the size of a down pipe being drilled through your wall.

Stopping cold air from being drawn into a room and preventing heat loss will reduce your energy bill markedly and make your rooms more comfortable.

Gapseal is protected by Intellectual Property Right with Patent Application number GB1121370.9

Customer Reviews

Our customers have given Gapseal an overall rating of 4.5 out of 5.

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Buy Gapseal Now

Gapseal is available in 10m rolls and each order is supplied with a FREE application tool.

Gapseal 10m Pack Suitable for 2 - 7mm gaps £13.99 inc VAT

Additional Application Tool Do I need an additional applicator? £2.29 inc VAT

Each order is supplied with 1 x FREE application tool as standard

Shipping Only: £ 1.99 Per Order (inc VAT)
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Beginning the installation of Gapseal Gapseal fitted to a sash window A finished window after gapseal has been installed