Sash Window Draught Proofing & Restoration in London

Sash Window Draught Proofing is a London-based specialist restoring period sash windows across Kensington, Chelsea, Belgravia, Mayfair, Hampstead, Richmond and the wider Home Counties. With 15 years of experience on Georgian, Victorian and Edwardian properties, we eliminate draughts, reduce noise and improve the thermal efficiency of original timber sash windows without compromising their heritage character.

Our craftsmen install discreet brush and compression seals, replace worn sash cords, refurbish parting and staff beads, and fit slim secondary glazing where extra insulation or acoustic performance is needed. Homeowners typically see a 30% reduction in heat loss and up to 75% less external noise after treatment — with no visible change to the original window fabric.

Call 0207 060 1573 for a free survey and quote, or read our detailed guide to how sash window draught proofing works.

Our sash window services

Restored Georgian sash windows in a London townhouse after draught proofing and secondary glazing

Sash window draught elimination — seals every gap around the sashes, meeting rails and beads.
Secondary glazing installation — slim internal units for maximum thermal and acoustic performance.
Secondary glazing vs draught proofing — compare costs, benefits and use cases.
Sash window restoration — full refurbishment of period timber windows.
Sash windows refurbishment — cords, beads, glazing and finishes renewed.
Sash window repair — stuck, rattling or broken sashes fixed.
Sash cord & rope replacement — genuine hemp cords and brass pulleys.
Heritage window restoration — listed buildings and conservation areas.
Victorian sash window draught proofing — specialist care for 19th-century joinery.
Thermal efficiency upgrades — reduce heating bills up to 30%.
Noise reduction for sash windows — up to 75% quieter interiors.
Window security solutions — discreet locks and restrictors.
Ongoing window maintenance — annual servicing for long life.
Emergency window services — same-day response for broken glass.
Cost of draught proofing — transparent per-window pricing.

What sash window draught proofing involves

Sunlit London Victorian living room with an original timber sash window after draught proofing

Draught proofing an original sash window is a joinery repair, not a retrofit product. We remove the sashes, renew the parting and staff beads, machine a discreet groove into the timber and set a conservation-grade brush or compression seal into it. The pulley stiles, meeting rails and box frame junctions are each treated in turn, because a single unsealed gap is enough to keep a room cold. Worn sash cords are replaced with waxed braided cord and the cast iron weights rebalanced so both sashes glide and hold at any height.

Because every element is reversible and nothing is visible from the street, the work needs no planning permission and is accepted on Grade II listed properties and throughout London's conservation areas. A typical London terrace of ten sash windows is completed in two to three working days, with no wet trades, no scaffolding and no change to the external elevation. All workmanship is covered by a 10-year guarantee.

Costs, savings and what to expect

Conservation-grade draught proofing costs £150–£300 per window in London in 2026 and cuts window-related heat loss by up to 30%, which in most period homes pays for itself within about two years. Where traffic noise or exposure is the bigger problem, internal secondary glazing at £400–£800 per window reduces heat loss by up to 70% and external noise by up to 50dB with acoustic laminated glass. Timber repair, splicing and cord replacement are quoted separately after survey, and our pricing guide sets out typical figures room by room.

Slimline secondary glazing fitted inside an original London sash window

The order of work matters. Seal and repair the original window first, then add secondary glazing only where noise or a cold, north-facing room justifies it. Our secondary glazing buyer's guide explains how to choose glass, frames and opening styles, and the sash window blog covers Part L 2026 compliance, listed building consent, condensation and restoration costs in detail.

Common questions

Will draught proofing change how my windows look?

No. The seals sit within machined grooves in the timber and are invisible when the window is closed. From the street nothing about the elevation changes, which is why the work is routinely approved on listed and conservation area properties.

Do painted-shut or stuck sashes have to be replaced?

Almost never. Sashes seized by decades of paint are eased, the cords renewed and the weights rebalanced so both sashes work again. Restoring an original window typically costs 40–60% less than replacing it with a modern copy, and keeps the original glass.

How long does the work take?

One to two hours per window for draught proofing, or a full day for a large bay. Most whole-house projects in London are finished within two to three days, and the property stays habitable throughout.

Which areas do you cover?

Central, West, North and South West London plus Surrey, Berkshire, Buckinghamshire, Hertfordshire and Kent. Call 0207 060 1573 for a free survey.

London areas we cover

Local sash window specialists across Central, West and South West London and the Home Counties:

See all areas we cover →

Why choose us

15 years restoring London's period sash windows
Fully insured with a 10-year workmanship guarantee
Conservation-friendly methods approved for listed buildings
Free on-site survey and fixed per-window pricing (£150–£600)
Rated 4.9/5 across 150+ homeowner reviews

Get in touch: 0207 060 1573 · info@sgs.org.uk · WhatsApp