Sash Window Installation Service in London

Sash window repair in London typically costs £150–£600 per window depending on the fault. Common repairs include sash cord replacement (£100–£200), re-balancing weights, and draught seal replacement. We offer a free site survey to assess your windows before any work begins.

Yes — we specialise in period property and listed building window repairs. Work on listed buildings requires like-for-like repair rather than replacement in most cases. We use traditional methods and materials that meet conservation area requirements. We can advise on planning considerations during your free site survey.

In most cases, repairing original timber sash windows is better value and more sustainable than replacement — especially for period properties. Restoration preserves the character of the building and is often significantly cheaper. We'll always recommend the most cost-effective option after assessing your specific windows.

Yes — we fit slim-profile double-glazed units into timber sash windows. Our double glazing for sash windows retains the traditional appearance while dramatically improving thermal and acoustic performance. This is particularly popular for Victorian and Georgian properties where replacing windows with non-original styles would be inappropriate.

Yes, Golden Ratio Sash Windows & Doors is FENSA registered. This means all replacement window and door work comes with FENSA certification — a legal requirement in England and Wales that confirms work complies with Building Regulations. Learn more on our sash window replacement page.

Yes — we offer a free no-obligation site survey across Greater London. A specialist will visit your property, assess your windows and doors, and provide a detailed written quotation. Call 020 3488 1695 or use our contact form to book.

Sash window draught proofing typically takes 2–4 hours per window. Most draught proofing jobs on a standard London terrace can be completed in a single day. Work can usually be carried out without the need to remove the windows.

Yes — we design and install bespoke timber bi-folding doors across London. All doors are handcrafted to your exact measurements and can be finished in any colour. Double glazed as standard.

We cover all of Greater London, with a focus on North, Central and West London. You can view the full list of boroughs we serve on our areas covered page. Contact us to confirm coverage for your postcode.

Yes — we specialise in matching existing period window styles. Whether you have Victorian double-hung sashes, Georgian six-over-six windows, or Edwardian casements, we can craft exact replicas or sympathetic repairs that preserve the character of your property. Read more about sash window styles.

In most cases, sympathetic repairs—such as splicing in new timber or re-puttying panes—do not require planning permission. However, if you live in a Conservation Area or a Grade II Listed Building and want to install double glazing or fully replace the windows, you will likely need consent. We always advise checking with your local London council, and we are happy to assist with providing architecturally correct specifications. See our heritage repairs and compliance guide for details.

A standard sash window repair and draught-proofing service usually takes about 1 day per window. Full sash window restoration and slimline double-glazing retrofits can take longer depending on the drying time of paints, epoxy resins, and the complexity of the period joinery.

Absolutely. Professional sash window draught proofing can reduce heat loss through your windows by up to 50%. It significantly lowers your energy bills, completely eliminates rattling sashes, and helps block out London street noise. For severe noise issues, check out our soundproofing sash windows service.

Yes, we are fully insured and offer a comprehensive guarantee on all our joinery, repairs, and glazing work. Please review our terms and conditions for full warranty details. As a FENSA-registered installer, you can rest assured that our installations meet the highest industry standards for quality and safety.