Sash windows specialists

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Our sash window specialists preserve traditional box sash windows and other styles, such as casement windows, french doors, bay and Bi-Folding doors. 

  • 500+ Happy
  • 8 Years Paintwork Guarantee
  • 20 Years on Repaired Parts
  • Google Rating

Chameleon sash windows specialist company provides wooden windows restoration services in East Anglia and South East. We work with private and commercial clients on all period properties, including timber windows repairs in Grade 2 listed buildings and heritage properties in conversation areas.

Our sash windows specialist services

Our wide range of services focuses on preserving traditional sash windows and making them as energy-efficient as modern “super windows”. 


Wooden window frame refurbishment

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Our windows specialists work with all types of timber frame issues. We restored thousands of sash windows over the past ten years. We know how to improve the durability of restored frames to make them as durable as timber windows made with Accoya wood.


To make this possible, we have developed our timber laminating method, which gives this extreme durability to original sash windows which went through our registration process.




Sash windows draught-proofing

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sash window specialists in draught-proofing



Sash window draught-proofing is a great option for Grade 2 listed buildings to remove rattling and draught. It does not require planning permission. We usually do window draught-proofing with timber frame repairs or double glazing retrofit.

Our team instals new staff and parting beads with draught-proofing seals and adds weather seals to the meeting rail. We can also draught-proof casement windows and french doors. 


Repairs and functional restoration

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  • Unblock stuck sashes

    Unblock stuck sashes

  • Repair broken cords

    Repair broken cords

  • Rebalance weights

    Rebalance weights

  • Replace Pulley

    Replace Pulley

  • Install restrictors & stops

    Install restrictors & stops

From sash cords repair, glass pane replacement, and window sill replacement to unblocking painted shut sashes. We can restore the functionality of your sash and casement windows. 


All sash window repairs are included in our sash window refurbishment & draught-proofing price


Double glazing specialists

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If you live in a period home with single glazing and would like to replace your windows to get all the benefits of double glazing, we have a perfect solution for you. We can reglaze your single-glazed windows with slim-profile double-glazing units. 


New vacuum double glazing is only 7 mm thick, so it fits perfectly narrow stiles and glazing bars of period sash windows. This new generation of glass has better thermal performance and U-value than double Low-E and 34 mm triple glazing. It also improves acoustic properties, and safety glazing is available for additional security. 

We specialise in sash window double glazing retrofitting

Our team of sash windows specialists can replace inefficient single glazing in the original box sash window with heritage double glazing. This will improve the energy efficiency of your traditional timber sash windows and reduce energy bills.  

The thermal photo below shows double-glazed sash windows by our team.

The window on the ground floor of the period property is single glazed, while the window above it has been retrofitted with slim-profile double glazing. As you can see, the thermal difference is huge. 

double glazing for sash windows thermal imaging

Traditional wooden sash windows can now be double glazed, so you do not need to go for a more expensive window replacement service. 

The new generation of double glazing (VIG – Vacuum insulated glass)

The new vacuum double glazing is 8 times more efficient than single glazing and four times more efficient than secondary glazing. This new glass technology is also more durable than standard double glazing insulated by inert gases such as Krypton and Argon.

U-value of different glazing solutions 

The U-value measures heat loss; it tells you how energy-efficient glazing is. The lower the U-value, the better thermal insulation glazing has.

  • Single glazing: 5.2 W/m²K
  • Regular double glazing (is not suitable for retrofitting): 1.2 – 1.9 W/m²K
  • Secondary glazing: 2.7 W/m²K
  • Triple glazing: 0.8 W/m²K
  • Our vacuum heritage double glazing: 0.7 W/m²K

We do not sell window replacements; we restore sash windows

Unlike other sash window companies, we primarily focus on timber frame restoration and double-glazing retrofitting; we do not sell new windows or double-glazed new sash inserts. Our expert team live and breathe the concept of repair rather than replace. 

We also do not make a miracle solution out of draught-proofings, which some companies sell as a solution for all energy efficiency problems. 

Our approach is direct and honest; we will only offer you a service which will solve your problem. Our staff who comes to the quote meetings are real window experts, not salespeople. 


For your peace of mind, our services come with guarantees from our company and manufacturers of products we use, such as vacuum double glazing, timber, and seals.

We offer 8 years guarantee on paintwork and 20 years on repaired timber window parts. The vacuum double glazing we use has 15 years manufacture warranty covering failed double glazed units. 

What Customers Say

We pride ourselves on delivering a high-quality job that our customers will be delighted with. Don’t just take our word for it, have a look at what our clients and customers have said about our services.

Really pleased with our windows! Prompt and helpful communication, extremely hard working team and a great looking (and hopefully better functioning) end result. Thank you!

Vanessa Nash

Alex and the team have restored our 20 year old sash windows so they look brand new. The team worked non-stop to complete it and made sure everything was to an excellent standard. Thank you.


We’re very happy with the work we recently had completed on the windows. It was also done in great time, with the guys coming nearly every day, including weekends – absolute grafters. Thank you, our windows look great!

Sarah Mayne

We had an excellent experience with Chameleon Decorators. The work was completed on time and to a very high standard throughout, all at a fair price. Would have no hesitation in providing a recommendation. Please note that the team work on the exterior only so you will need to factor in an internal job also!

Oliver Taylor


Very pleased with the results, very professional service. Would recommend.

Stephen Mcmullen

Excellent communication, service and professionalism. We spoke with Chameleon to restore some rotting wood french doors and wooden windows, as well as redecorate. We’d use them again without hesitation and would thoroughly recommend them.

Jamie Newman

Alex and his team are superb. We have used them before, and always been impressed – as we were this time – by their work ethic, their expertise and knowledge, the quality of their work, and their efficiency. I recommend them very highly indeed.

Emma Goddard


Our completed projects

    Windows refurbishment in Care home – Old Vicarage Care Home, St Neots

    Windows refurbishment in Care home – Old Vicarage Care Home, St Neots

    Sash windows restoration in Suffolk

    Sash windows restoration in Suffolk

    Sash windows restoration in Cambridge

    Sash windows restoration in Cambridge

    Sash Window Refurbishment in Hertfordshire

    Sash Window Refurbishment in Hertfordshire

    Retrofitting original sash windows with double glazing in Suffolk

    Retrofitting original sash windows with double glazing in Suffolk

    Double glazing retrofitting in Wing

    Double glazing retrofitting in Wing

Contact us for a free quote

If you are looking for reliable and professional sash windows specialists with executive customer service in your area, look no further than Chameleon Windows! Contact our friendly team today, and we will be happy to restore your windows.