The 50-year sash window

Here at Sash Windows of London, we’ve had a long time to perfect our design and manufacturing process. The result is a broad range of high quality sash windows, built to your specifications, with your choice of a combination of economy, standard or premium materials.

Nearly 40 years of research, practise and response to customer feedback has not been wasted, and we’re now more proud than ever to show off what we can do for you.

Built to Order

Because we control the whole process – from design to manufacturing to installation – we can make sure that the product you receive is always exactly the product you need. We’ll take note of any specific requirements you’ve got during the quote process so that you know you’ll be satisfied with the windows you receive.

Built to Function

It goes without saying that the quality of the glass that goes into your windows is crucial. With our high-performance 24mm double-glazed units, we make sure that light gets in, heat stays in, and noise stays out. You can also choose from our range of optional extras, from top-end A rated glazing to strengthened security glass, to make sure you get what you need.

Built to Last

By combining traditional joinery techniques with cutting edge materials, we are able to ensure maximise our windows’ durability and longevity. The Accoya® timber we use is strong and hard-wearing and is guaranteed against rot damage for 50 years. On top of that, our high quality micro-porous paint solutions will ensure a long-lasting finish.

Sash Window Features

Key benefits

  • CLASS 1 DURABILITY – 50 year anti-rot guarantee
  • STABILITY – Up to 80% swelling/shrinkage reduction compared to other woods
  • OPTIMAL INSULATION – High quality double glazing provides optimal heat and sound insulation
  • ROBUST CONSTRUCTION – Time tested mortice & tenon joints in all windows
  • LASTING FINISH – Low maintenance micro-porous paint systems last for years
  • TIMELESS DETAILS – Tradition features and designs employed throughout our range


Casement Window Accoya Wood

95% of our sash windows are made using sustainably sourced Accoya® wood. Accoya® is a form of high-performance timber modified through a process called acetylation. This gives strength and durability rivalled by only some of the very best non-sustainable tropical hardwoods. It is also perfect for finishing using our microporous paint systems, with very little preparation required between coatings.

Accoya® timber is the result of 80 years of extensive research and development, and it’s what gives our sash windows their unparalleled longevity.


Glass & Glazing

Our windows come with high-performance 24mm double glazing as standard, with 16mm cavities filled with argon gas and a Warmed Swisspacer bar separating the two panes. This means optimal thermal and audio insulation, with heat and sound both staying on the right side of the window. We can offer an upgrade to top-end A rated double-glazing for extra insulation if you need it. Additionally, with a 1.2W/m2k indicative centre pane U-Value, you can be sure that light can travel through uninterrupted.

Our specially developed vented rebate system is available as an optional addition. With these subtle holes running through the window frames, we can add to the already lengthy lifespan of your units.

Everyone has different specific requirements, and we’re happy to cater. Here’s a list of some of the optional extras we can offer:

  • Hardened security glass
  • Laminated glass, also for added security
  • Sandblasted or otherwise textured/obscured glass for extra privacy
  • Stained or patterned glass
  • Acoustic glass to further protect against noise pollution (up to 35db Rw)
Casement Window Double Glazing Technical Data


Sash Window Teknos Low-Maintenance Microporous Paint Systems

Thanks to the Teknos micro-porous paint systems we use to finish our windows, applied by expert spray technicians with end grain sealing, you won\\\’t need to keep re-coating your windows every year or so. And because of the quality of the Accoya® timber being painted, when you do come to redecorating, you\\\’ll only need to apply a single top-coat.

We can also colour match any Dulux, RAL, Crown or Farrow & Ball paint so that your windows match the rest of your house.


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