Frequently asked questions

Welcome to our Frequently Asked Questions section! Here, we will answer some of the most common queries that we receive about our sash window restoration services.

This information will hopefully help you to be better informed about what we do and how we can help you.

One of the most common questions we get is about the cost of sash window refurbishment and double glazing, for this reason, we have created a dedicated page to answer this question properly, here is the link to this page. Sash window restoration can become a costly undertaking if you decide to retrofit new vacuum glazing to your old frames. However, we always aim to be competitively priced and offer a free quote so that you can make an informed decision.

Wooden window renovation

What kind of wood do you use?

In our timber window restoration projects we use Accoya and Tricoya wood.

Do you repair windows on Grade 2 listed buildings?

Yes, we regularly work with Grade 2 listed buildings and conservation area properties. We do like-for-like timber frame repairs. They do not require planning permission as we do not change the look of the windows.

Can you unblock stuck or painted-shut windows?

If your sash windows are stuck or painted shut we can unblock them, either by removing the problem paint during the restoration process, or by changing sash cords, pulleys and rebalancing weights if needed to return windows to full functionality. We do these repairs as a part of larger window restoration projects.

Can you replace broken glass panes?

We can replace broken or cracked glass. We also ensure that the new glass thickness and texture match that of the original glass.

What does the 20 year guarantee on repairs cover?

For your peace of mind, we offer a 20 years guarantee on all Tricoya and Accoya timber repairs, which means no rot on parts that we repair during the next 20 years or we will come and fix the rot for free.

What is the lead time to get the exterior window renovation work done?

Generally speaking, a 15 window project will take us 5-7 days.

How much will it cost to renovate my sash window?

Sash window refurbishment work starts at £500 per window. The cost will depend on a number of factors such as the size of the window, whether it requires glass or sill replacement, draught-proofing installation, functional restoration etc. The cost also depends on the number of windows and access to them. If you live in a busy high street with limited access to the windows, the cost per window will be significantly higher.

Windows painting

Do you offer a guarantee on paintwork?

We offer 5 or 8-year guarantees on paintwork if the timber renovation was done by us. This is 5 years on darker colours and 8 years on white. The guarantee covers flaking, bubbling and peeling paint issues.

Do you paint windows from the inside?

We only work with the exterior side of the windows. If a window is rotten throughout, we will carry out repairs on both sides, leaving the interior part of the repairs ready for painting.

Can you paint windows during low-temperature months?

We are able to paint windows throughout the year. We can operate in temperatures as low as 0 °C giving us the flexibility to carry out work as and when it’s required.

How closely can you match the colour?

We can match a required paint colour with a 90-100% accuracy. Most trade decorating centres only have 1 paint tinting machine. We work with paint suppliers with 3 different machines, each covering a wide range of colours and shades. If we cannot match your colour, it is very unlikely anyone else can.

Double glazing installation

Can you install double glazing into the existing timber window frames?

Yes, we can remove old single glazing and replace it with ultra-thin double glazing. Single glazed windows can now be converted to double, without changing the frames. 

Do you only install double glazing into sash windows?

We carry out the retrofit installation of double glazing into all types of timber frame windows and doors, including box sash windows, casement windows, bay windows and french doors.

My windows are rotten, can you still double glaze them?

We repair rotten windows frames prior to double glazing installation by removing and replacing rotten timber frame parts with new solid Accoya timber. Here you can see a range of before and after timber frame repair photographs.

Can you double glaze period sash windows with Georgian bars?

We can double glaze period Georgian sash windows, please check a case study: Georgian sash window double glazing installation.

What is FINEO double glazing?

FINEO glass is the latest generation of vacuum-sealed double glazing units, which have equal properties to triple glazing. To find out more information about fINEO glass, please follow the link.

Do you work with regular gas-filled Slim-profile double glazing?

We do not, we only work with FINEO because it gives 15 years guarantee on double glazing units and has life expectancy of 25+ years while regular heritage double glazing manufacturers only give 5 years guarantee, this is due to some key issues with slim double glazing.

Will double glazing reduce outside noise?

Yes, the FINEO vacuum slim-profile glazing we use offers soundproofing qualities to other insulating glass products available on the market such as double or triple glazing. In relation to traffic noise specifically, Fineo glass provides around a 10 dB reduction, which translates to a perceived decrease in noise by around half.

Will my windows look the same after double glazing retrofitting?

Due to the thickness of vacuum double glazing, which is only around 4 mm thicker than single glazing, you will not notice the difference. After restoration, double glazing and re-decoration, your windows will look new and refreshed but crucially not lose any of their original characters. Visit our projects gallery which has many photographs of windows after double glazing was retrofitted.

What is the lead time to get my windows double glazed?

The most time-consuming stage is the FINEO glass production itself, which takes place in Belgium. From placing the order to delivery, the lead time is 8-16 weeks at present (Summer 2021). We work around the glass delivery schedule, so we get the glass installed into your windows as soon as it arrives in the UK. The typical 15-20 windows double glazing project will take us, on average, 2 weeks.

Do you work with Grade 2 listed properties?

We can install double glazing into windows in grade 2 listed properties, but you will need to apply for planning permission prior to any work commencing.

Will you need to remove windows from the frame?

Yes, but they will be reinstalled into the frame on the same day before night.

When you install double glazing, do you also repair timber, adjust mechanisms and re-paint windows afterwards?

When we do double glazing installation, the restoration, draught-proofing, functional restoration and windows painting all come as a part of the full window upgrade service package. 

Will you take my windows away for double glazing installetion?

No, we do all work onsite in our mobile gazebo workshops.


Are you insured?

Our public liability insurance: £5m

What is the process if I want to arrange a meeting for a quote?

Just get in touch with us by filling out the contact form on our website or simply call us on 01223504315

What is your company VAT number?

CDC RESTORATION LTD VAT number: GB 270216336

What is your company registration number and registered office address?

Chameleon Decorators & Windows Restoration is the trading name of CDC RESTORATION LTD, Company number 06539664. Registered office address 3 Harness Close, Trumpington, Cambridge, CB2 9PS.

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