Sash Window Installation Service in London

Sash window repair in London usually runs somewhere between £150 and £600 a window — it really depends what's actually wrong. A snapped cord is normally £100–£200, and re-balancing the weights or sorting the draught seals sits around the same mark. We'll come out and look at your windows for free before we put a price on anything. See our full price guide.

Yes, that's a big part of what we do — period property and listed building window repairs. On a listed building you normally have to repair like-for-like rather than rip the frames out, so we stick to traditional methods and materials that keep conservation officers happy. We'll talk you through the planning side when we come out to survey.

Nine times out of ten, repairing the original timber works out cheaper and greener than replacing — especially on a period place. You keep the character of the building and the bill is usually smaller. That said, we'll be straight with you: if a frame is genuinely too far gone, we'll tell you.

Yes — we retrofit slim-profile double-glazed units straight into timber sashes. Double glazing for sash windows keeps the traditional look but makes a real difference to warmth and noise. It's a popular choice on Victorian and Georgian homes, where modern replacement windows would look completely wrong.

We are. Golden Ratio Sash Windows & Doors is FENSA registered, so any replacement window or door work comes with FENSA certification — that's the bit that proves the job meets Building Regulations, which is a legal requirement in England and Wales. There's more on our sash window replacement page.

Yes, and there's no charge for it. One of our team will come out anywhere in Greater London, take a proper look at your windows and doors, and put together a written quote. Give us a ring on 020 3488 1695 or drop us a line through the contact form.

Draught proofing a sash is usually a 2–4 hour job per window. On a typical London terrace we can normally get the whole house done in a day, and most of the time we don't even need to take the windows out to do it.

Yes — we make and fit bespoke timber bi-folding doors all over London. Every set is built to your exact measurements, finished in whatever colour you like, and double glazed as standard.

All of Greater London, though most of our work is North, Central and West. There's a full list of the boroughs we cover on our areas covered page — and if you're not sure about your postcode, just ask and we'll confirm.

Yes, matching original styles is something we do a lot. Whether it's Victorian double-hung sashes, Georgian six-over-six, or Edwardian casements, we can make exact replicas or carry out sympathetic repairs so it still looks right for the property. There's more on sash window styles if you fancy a read.

Usually not. Sympathetic repairs — splicing in new timber, re-puttying panes, that sort of thing — don't normally need permission. It's different if you're in a Conservation Area or a Grade II Listed Building and you want double glazing or full replacements; then you'll likely need consent. We always say check with your local council first, and we're happy to provide architecturally correct specs to help. Our heritage repairs and compliance guide goes into more detail.

A standard repair and draught-proof is about a day a window. A full sash window restoration or a slimline double-glazing retrofit can take longer — a lot of it comes down to drying times for paints and epoxy resins, plus how fiddly the original joinery is.

It really does. Decent draught proofing can cut the heat lost through your windows by up to half. You'll feel it on your energy bills, the rattling stops completely, and it takes the edge off London street noise too. If noise is the main issue, have a look at our soundproofing sash windows service.

Yes. We're fully insured and everything we do — joinery, repairs, glazing — is guaranteed. Full warranty details are in our terms and conditions. And being FENSA registered, you've got the reassurance that our installations are signed off to industry standard.