Old - Single glazed wood sash windows x 8 New - Double glazed upvc wood grain sash windows x 8 SJB Windows were BRILLIANT! Quote - good value, precise and beat numerous other FENSA compa... See more
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We’re a family-run business specialising in both manufacturing and installation of traditional sash windows. Although we mainly install our sash windows in London & the south-east of England, our sash window services reputation is known much further afield.
United Kingdom
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Website, communications, site visit and getting a quotation was handled well. Competitive price quoted. Lower than competitor we'd shortlisted. Able to schedule a slot for installation more swiftly than expected. Work was carried out professionally and a high standard.

Reply from Sjbsashwindows
The window installers were efficient, polite and took loads of care. They clearly loved installing the windows and were proud of how good it looks. As are we!

Reply from Sjbsashwindows
I had a great experience with SJB replacing wooden 3-bay sash windows. The whole process was efficient and professional from sales through to survey and installation. I found the team very helpful and pleasant to deal with (answering all my many questions with patience!). The installation went smoothly with very little mess and the windows look great.

Reply from Sjbsashwindows
We had PVC replacements of both sash and casement windows fitted. The fitters (Cydrell and Dominic) were extremely professional and worked rapidly finishing the whole house within a week. The disruption during fitting and retouch painting needed afterwards was much less than expected. The new windows look great!

Reply from Sjbsashwindows
The three guys (CJ, Leroy and Blogi) were all really conscientious and hard-working professionals. I had 10 windows replaced and they clearly realised that it was a big and stressful deal for me - so did their level best to proactively reassure me and to explain what they were doing. No detail was too small for them and they never made me feel that I was pestering them (even when I relayed on concerns from the block management). I was very grateful to them for working so hard to clean up the dusty mess afterwards.
All in all, this job went just about as smoothly as possible.

Reply from Sjbsashwindows
First rate service from this well-established family firm – from initial contact through to the final invoice. Very well-made windows, professionally installed. Competitively priced.

Reply from Sjbsashwindows
Overall the experience with SJB Windows was good with prompt email communications, helpful staff and a clean and efficient window installation. The only fly in the ointment was an unforeseen and fairly last minute change in the installation date which, fortunately, was ok.

Reply from Sjbsashwindows
Very professional from start to finish, friendly service, clear communication and excellent quality installation. I would definitely recommend!

Reply from Sjbsashwindows
Incredibly knowledgable and did an amazing job replacing a window. We loved it so much we are having them back to replace more

Reply from Sjbsashwindows
Extremely polite and professional team of people. The man who came to look at the job gave me information and advice on all the options open to me. The quote, with said options, came through very quickly. I was given a date when the work was likely to begin and received frequent updates in the lead up to that date. The chap who came to fit the windows was polite and friendly, fitted the windows with care and attention and cleared up very well before he left.
Couldn’t ask for more and would definitely recommend.

Reply from Sjbsashwindows
SJB sash windows were helpful and efficient at each stage of the process from early advice and estimates through to final installation. We have returned to them three times which demonstrates our confidence in the company and we’d have no hesitation recommending them to others.

Reply from Sjbsashwindows
Just had windows and french doors put in my garage conversion. Communications could definitely do with some work but the product is excellent and the installation was quick and done to a high standard. Will use them again for sure.

Reply from Sjbsashwindows
Very thorough initial consultation with clear explanation and time spent.
Installation was faultless, constantin was professional, efficient and it was a very positive experience all round. No mess and a lovely job.
Lovely quality window and a perfect replacement for the victorian sash.

Reply from Sjbsashwindows
Old - Single glazed wood sash windows x 8
New - Double glazed upvc wood grain sash windows x 8
SJB Windows were BRILLIANT!
Quote - good value, precise and beat numerous other FENSA companies.
Queries - always efficient in answering any questions which were many. As you can imagine, fully replacing all windows is costly and time consuming so finding the right company is very important.
Installation - Internal so no need for scaffolding and all completed by the amazing Constantin whom removed old and then installed 8 new sash windows in only 5 days (originally expected 8 days!) in addition to leaving my home tidy everyday he was there.
My appreciation to SJB Windows for making the process run smoothly!

Reply from Sjbsashwindows
your installers were fast ,efficient and very tidy .Some of the finishing around the windows could have been neater but overall very good.

Reply from Sjbsashwindows
Fantastic windows, we are really noticing the difference in sound and temperature! The office and installations teams are all very professional and friendly, leaving the place nice and tidy. Really happy with the finished result 8 windows later in 3 phases. I highly recommend SJB.

Reply from Sjbsashwindows
Feedback in response to SJB Sash Windows comments of 27/08/25:
Thanks for reiterating your perspective however, it is not helpful or indeed fair to dismiss the building contractors assessment as them trying to cover for their poor work, I will of course let them know what you think.
It is 'interesting' that there have not been any issues with the rest of their work, its only this cill? It is also 'interesting' that the damaged cill was also uniquely subjected to the installers dragging the two new windows across it along with some of their equipment as well as the physical forces to remove the frame from the surrounding wall?
It may be 'unusual' for someone to come back after 2 years but that doesn't discount their case. I've already acknowledged that I cannot prove definitively what caused the damage however, there is a lot of circumstantial evidence which you seem very happy to discount.
It is unusual however, for a company to refuse to even consider that their might be something to learn, something that they might help put right.
Feedback in response to SJB Sash Windows comments of 26/08/25:
Like most customers I assumed (perhaps naively) that any damage done would be repaired. I did highlight that because none of my photos of the before and after included the cill, I could not show definitively that this was done by the window installers so I sought the advice of the builders who carried out the external works the previous summer. They reassured me as the work they did to properly repaired this cill and as I had full confidence in them given the condition of all the other works they carried out, I asked them to call you and detail this for you to consider. However, you were not interested in hearing them and seemed to revel in sending me the Ts&Cs, it felt like a real 'we told you so' moment. As I stated, I never expected you to accept full responsibility but I had hoped for some compromise especially given the significant amount of money I spent with SJB, instead I was told tough luck. It doesn’t feel like a good customer experience.
Original feedback:
3 years ago the house I live in underwent major external works including repointed the brickwork, repairing and painting windows and cills. 2 years ago, I replaced 2 windows using SJB sash windows. The brothers who installed them for SJB, needed to come back to change the internal fixtures which were installed incorrectly. It took 3 attempts to get them to do this. With all of this, and as I had focused on the inside issues, I did not take photos of the outside walls or cills as well.
This summer, the builders who did the original work on the outside of the building checked the cills. The crack they had repaired had opened up again. When I asked what caused this, they said it was likely that the work done to remove the old window had done it. There is no other explanation for this damage, plus the none of the others cills are damaged. They even rang SJB on my behalf to detail their previous work to repair this cill but SJB weren’t interested.
SJB refused to acknowledge any responsibility and quoted the small print and legal clauses. I never expected them to take responsibility but hoped for some compromise but they refused point blank which is disappointing. I also understand SJB have since parted ways with the workers who installed my windows.
Advise to all, take photos not only of the windows and surrounding fixtures inside but also the outside surrounds of the window, the cills, the walls and mouldings plus check the materials used, before and after any works carried out.

Reply from Sjbsashwindows
We had three new windows fitted. Communication was excellent throughout the process and the quality of work was great

Reply from Sjbsashwindows
We had a new door and 6 sash windows fitted by SJB.
From the initial quote to the fitting they were pleasant, quick and professional. Very happy with the results and would use them again.

Reply from Sjbsashwindows
We engaged SJB Sash Windows to install new sash windows in our home, prioritising improved soundproofing because we were about to welcome a newborn. From the outset, communication was polite and prompt, but unfortunately the overall experience has been quite disappointing.
Quality of Installation
The installation was plagued with problems from the start. Several of the latches did not rotate smoothly, catching or sticking, which made them difficult to use. One of the windows was almost impossible to open and is still a lot stiffer than the rest. Most concerningly, one of the windows was installed incorrectly with the sash weights the wrong way around, which meant it couldn’t operate properly and immediately required remedial work. This remedial work resulted in scratches, gouges, scuffs, and chipped paint on the woodwork — an unacceptable standard given this was a premium product. One fitter even left paintbrush remnants in our bathroom drain, blocking it for days until we discovered the cause - perhaps an indication of general carelessness. Despite multiple return visits, the finish remained below what we would expect and left us with windows that still don’t feel right.
Soundproofing Claims
A major reason for choosing these windows was the promise of significantly reduced outside noise. We were told to expect about a 65% improvement, especially with the upgraded acoustic glazing. In practice, there has been no measurable improvement, even after checking with a decibel meter. The company later clarified the reduction figures applied only to the glass itself rather than the room as a whole. This felt extremely misleading, given we had made our soundproofing priorities crystal clear from the beginning.
Customer Service
The team were generally polite and responsive in arranging follow-up visits, but coordinating them became stressful and time-consuming, particularly while juggling life with a newborn. There was no goodwill gesture or discount offered despite the inconvenience and substandard finish. Multiple remedial visits took up our time and energy and undermined our confidence in the quality of the work. It took many messages, calls, and repeated visits to address the same points, which left us exhausted and discouraged from continuing.
Overall
We paid a substantial amount for what we hoped would be a high-quality, low-hassle installation. Instead, the result was multiple remedial visits, a lack of confidence in the soundproofing claims, and ongoing frustration. While the company seems willing to try to fix mistakes, we did not feel they ever fully acknowledged the shortcomings in their sales messaging or the overall customer experience.
We are now left with a product that we do not feel delivers on its promises, and with some damage to surrounding paintwork in our home that we will likely have to rectify ourselves.
I would suggest anyone considering SJB Sash Windows take great care to get all guarantees and performance promises in writing, and to be prepared for a potentially drawn-out aftercare process if things go wrong.

Reply from Sjbsashwindows
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