Endorsed by Which?

Core Sash Windows

4.6

60 Reviews

Opening Hours
Today - 08:30–17:30
  • Monday 08:30–17:30
  • Tuesday 08:30–17:30
  • Wednesday 08:30–17:30
  • Thursday 08:30–17:30
  • Friday 08:30–17:30
  • Saturday - Closed
  • Sunday - Closed

Why you can trust this trader

After undergoing rigorous assessment to become endorsed, every Which? Trusted Trader agrees to our Code of Conduct. This gives consumers the reassurance that they have the best possible protection and adds an extra layer of security to ensure best practices and procedures are followed. Which? fully investigates any breaches and will take any necessary action to ensure consumer protection.

About

Core Sash Windows is a London-based double-glazing company specialising in the replacement and repair of traditional timber-framed windows and doors. We understand that replacement windows and doors are an important investment, and you obviously want to make the correct choice.

That is why we offer:

• Elegant and traditionally styled products
• Attentive customer care
• Punctuality and reliability
• Considerate workmanship
• Convenient and fully comprehensive service
• No need for Third Party trades

That is why we promise:

Our surveys are always performed by experienced carpenters instead of designated sales-people - there's no unnecessary up-selling and no high-pressure tactics. Our FENSA-registered installation service also includes the hand painting of your new products, traditional sand-and-cement pointing joints, and the repair of any damaged plaster. And our traditionally designed windows and doors come with a 10 Year Insurance-Backed Guarantee.

What we do

  • Glaziers

    • Sash windows
    • Timber windows
    • Window consultants
    • Replacement window services and repairs
    • Double glazing installation
    • Aluminium Windows
    • Double glazed units
    • Double glazing repair
  • Double glazing

    • Double glazing installation
    • Double glazing suppliers
    • Double glazing repairs
  • Carpenters

    • Joinery and carpentry
  • Doors

    • Bi-fold doors
    • French doors
    • Front door
    • Patio doors
    • Timber doors
    • UPVC doors
    • Orangeries
  • Draughtproofing installers

  • Specialised building trade contractors

  • More Services

    • double glazed timber sash casement windows and doors

Customer reviews

Why you can trust these reviews

All reviews are verified as being genuine and a true customer of this trader.

How can we be so sure?

100% of the reviews we publish have been through our stringent moderation process.

4.6
60 reviews
Customer Service
4.6
Quality
4.7
Value
4.6
Sort by
Professional and good quality
Customer Service
Quality
Value
I had a two wooden sash windows, French doors, a leaking pane on an existing window and the borrowed light above the front door replaced. Core were very efficient and easy to deal with whilst getting the job set up (arranging surveys etc.), got back with answers to questions and were very clear about what their service entailed. The window fitters and decorator were professional and worked to finish the job whilst I was away. They made a good effort at cleaning up too. Their service includes a decorator to make good on any damage to the window surrounds and ensure that the windows are fully decorated and don't require the customer to finish off. They even sourced matching paint for windows that were painted non-white. The one item of snagging was resolved quickly - I reported it on a Sunday evening via e-mail and they had a surveyor round by 1030 Monday morning, with the snagging resolved on the Friday. The products are good quality with attention paid to the security of the windows and doors they are fitting.
Customer in Greater London Posted on 27/10/2024 , work completed 25/10/2024
Trustworthy, skilled and considerate
Customer Service
Quality
Value
I value professionalism and service. A neighbour referred me to Core Sash Windows many years ago, but I also did my due diligence. I was impressed by the information and advice given to me during the quotation process, and they were very reasonably priced, given the high quality of the windows. Fast forward several years, I've had them back many times to replace various windows in my house where the old original sash windows had rotted away. I've also recommended to others. The teams of installers work like trojans. They are clear in explaining the installation process and are exceptionally clean and tidy. They also bring craft and art to how they work, which is important when you are trying to achieve a particular aesthetic in keeping with the period of the home, in my case, a Victorian terrace. The administration/support team updates you on installation timelines and quickly answers any questions. You get the sense that people have worked with Core Sash Windows for a while and like their workplace, which is essential to me. Their windows have totally transformed my house. While the window materials are exceptional, and the action of the window - the way it opens and closes - is wonderfully smooth and noiseless. It has transformed my home, and I recommend them without any caveats. Top marks
Customer in Greater London Posted on 02/09/2024 , work completed 03/08/2024
High Quality workmanship, considerate craftsmen
Customer Service
Quality
Value
Virtually all Victorian sash and casement windows replaced with new double-glazed equivalents. The windows, as delivered, seem to be very high quality and the installation work, which could have been very disruptive, was carried out very efficiently and with maximum consideration for our having rooms to live in. The team were a pleasure to deal with. They cleaned as they went on and helped put back the curtain rails and curtains, not only helping me but ensuring I did not damage up the new windows! The windows are not the cheapest but I don't think they could be faulted for quality or for finish.
Customer in Greater London Posted on 30/07/2024 , work completed 29/07/2024
Perfect from start to finish!
Customer Service
Quality
Value
We have had 7 windows replaced by Core Sash Windows, and are absolutely delighted with the work they have done for us. From our initial appointment with Ryan to the actual work days with the window installer (Irmis) and the painter (Andrew), everything has gone smoothly without a hitch. The quality and cleanliness of the work, as well as their professionalism exceeded our expectations. We would warmly recommend them!
Customer in Greater London Posted on 15/09/2023 , work completed 09/09/2023
Highly recommend
Customer Service
Quality
Value
I live in a listed building so our design constraints are very tight. I'm very pleased with the service and the product. Incredible work from the whole team! Some mistakes were done at the start but what really matters is how well they dealt with it. It's an honest business that cares about their customers. I'll surely be using their services again.
Customer in Greater London Posted on 19/01/2023 , work completed 11/01/2023
High quality of work
Customer Service
Quality
Value
Had new French Doors installed and the fitters were efficient, took great care to isolate disruption and cleaned up perfectly. The decorator who came the next day was meticulous and again left no mess at all. Not all companies will make good and redecorate around their work like this.
Customer in Greater London Posted on 13/10/2022 , work completed 22/10/2007
quality, professional service
Customer Service
Quality
Value
Tim and the team were professional, efficient and responsive. They were flexible with our schedule and we very really impressed with the quality of their work. Highly recommended.
Customer in Greater London Posted on 10/10/2022 , work completed 01/09/2022
Brilliant professional work and very friendly
Customer Service
Quality
Value
Throughout the process everyone we met and spoke to were knowledgeable, professional and completed the work to a very high standard. Responsive and friendly from start to finish. The window itself was fitted and finished neatly, work was very tidy and quick, and looks great! Would definitely recommend.
Customer in Greater London Posted on 21/07/2022 , work completed 15/07/2022
Fantastic
Customer Service
Quality
Value
I could not have asked for a better outcome when having full box replacements for my sash windows (based in London Fields, Hackney). Work was carried out to a high standard, efficiently and throughout installation the property was kept clean and protected from the risk of dust and potential damage. Special thanks go to Tim and Nicu who were brilliant. I have no hesitation in recommending Core or using them again in the future.
Customer in Greater London Posted on 07/05/2022 , work completed 21/04/2022
Result very good
Customer Service
Quality
Value
We used Core Sash Window on 3 separate occasions for a total of 8 windows and we are very satisfied with the end result. Communication was easy and they responded quickly when problems occurred. They do need careful managing.
Customer in Greater London Posted on 15/09/2021 , work completed 04/08/2021