Specialist repair, draught-proofing and slim double glazing of original timber box sash windows in London’s Georgian, Victorian and Edwardian homes. We splice and renew only the timber that has failed, re-cord and re-balance the mechanism, seal out draughts and rattle, and redecorate to a lasting finish — keeping the character of your period windows while making them warm, quiet and effortless to use. Conservation-area and listed-building specialists.
The original timber box sash windows in a London period home are one of its most valuable features — and one of the most misunderstood. Double-glazing salespeople will tell you they are beyond saving and must be ripped out for modern units. In nearly every case that is simply wrong. The Georgian, Victorian and Edwardian sashes in Hampstead, Belsize Park, Highgate and across the capital were made from slow-grown, tight-grained heart pine that is denser, more stable and more rot-resistant than anything you can buy new today. A window that looks tired, draughty and seized solid is almost always sound underneath a century of paint and neglect.
At Hampstead Renovations we restore those windows rather than discard them. We replace only the timber that has genuinely decayed — usually a cill, the bottom rail or a short section of box — splicing in matching new wood and keeping the rest. We re-cord and re-balance the mechanism so the sashes glide and stay put, draught-proof the whole window so it no longer rattles or whistles, and redecorate to a finish that lasts. The result is a window that performs like new but keeps the wavy original glass, the slim glazing bars and the honest joinery that a plastic replacement can never reproduce.
It is also the better financial decision. Restoration typically costs less than wholesale replacement, adds value rather than stripping a period property of its character, and avoids the planning problems — or outright refusal — that replacing original windows can trigger in a conservation area or on a listed building. Done once, properly, a restored sash window will outlast the people who commissioned the work.
Three faults account for almost everything we are called to fix. Sashes stick because decades of overpainting have glued them to the frame and the timber has swollen. They rattle and leak because the staff and parting beads have worn and there was never a draught seal. And they drop shut or won’t stay open because a sash cord has snapped or a counterweight has come off its knot inside the box. None of these is a reason to replace a window — each is routine restoration work that we put right permanently.
Owners come to us when a previous “quick fix” has failed, when a survey or a freeholder has flagged the windows, or simply when a beautiful room is unbearably cold in winter. What they want is warmth, quiet and smooth operation without losing the windows that make the house worth living in. That is exactly what specialist restoration delivers.
A traditional box sash is a precise piece of engineering — two glazed sashes counter-balanced by weights on cords running over pulleys inside a hollow boxed frame. We service every component so the whole window works as it was designed to.
Easing, re-squaring and repairing the moving sashes; splicing decayed rails and stiles; reinstating lost glazing bars and mouldings to the exact original profile.
Renewing perished cords with waxed sash line, re-hanging and balancing the cast-iron weights, and servicing or replacing the brass pulley wheels so the sash holds at any height.
Repairing or renewing decayed cills, pulley stiles and box linings with matching timber, and re-making the parting and staff beads that hold the sashes in their runs.
Routing concealed brush-pile seals into the beads and meeting rails to stop draughts, rattle and noise — invisible from the room and the street.
Re-puttying loose panes, replacing cracked or fogged glass, and fitting slim-profile double-glazed units into deepened or new sashes where the property allows.
Repairing or replacing fitch fasteners, sash lifts, pulls and travel stops in period-correct finishes, so the window is secure and a pleasure to use.
London’s building stock spans three centuries of sash design. We recognise and respect the detailing of each — the proportion of the panes, the thickness of the bars and the way the boxes are built.
Six-over-six small panes divided by fine glazing bars, often with crown or cylinder glass. We preserve the delicate bar profiles and original glass wherever possible — the detail that makes a Georgian elevation.
Two-over-two or one-over-one sashes with larger panes made possible by stronger plate glass, frequently with horns on the upper sash. Common across Hampstead, Belsize Park and Islington terraces.
Multi-pane upper sashes over a single lower light, leaded or margin-glazed detail, and broader proportions. We match the characterful upper-sash patterns precisely.
We also restore margin lights, curved and bay-window sashes, sliding box sashes in mansion blocks, and Yorkshire horizontal sliders. If your windows form part of a wider scheme, our period property restoration and heritage restoration teams handle the whole building under one contract.
Every project follows the same disciplined sequence, whether it is a single stuck window or every sash in a five-storey townhouse.
We inspect every window, test the timber for decay, check the cords and weights and assess glazing and planning status — then give you a fixed written quotation, not a phone estimate.
Sashes are eased out, beads removed and the room protected with dust sheets and floor boards. Where work is done in situ we keep the opening weather-tight throughout.
Failed paint is stripped back, decayed timber cut out and matching new wood spliced and glued in. Joints are re-wedged and the sashes squared so they run true.
New waxed cords are hung over serviced pulleys, weights re-tied and balanced, glass re-puttied or upgraded, and the sashes set to hold at any height.
Concealed brush seals are routed into beads and meeting rails, new parting and staff beads fitted, and the sashes refitted to run smoothly and silently.
We prime and finish with a flexible microporous system, clean down, and walk the work with you. Everything is covered by our written workmanship guarantee.
The single most cost-effective thing you can do for a cold, draughty period room is to draught-proof its sash windows — and done well, it changes nothing about how the window looks. We rout a slim channel into the staff bead, parting bead and meeting rails and seat a brush-pile or wool-pile seal inside it. The seal is hidden within the window, so from the room and from the street the sash is unchanged, but the gap that let cold air pour in is closed.
The effect is immediate: no more rattle on a windy night, no whistling around the sashes, far less dust and traffic noise, and a noticeably warmer room that holds its heat. Because the sashes now run in a guided channel they also operate more smoothly than they did before. For most owners, draught-proofing alone transforms how a period room feels in winter — before any question of new glass arises.
Draught-proofing pairs naturally with our wider house refurbishment and flat refurbishment work, where we coordinate windows with insulation, decoration and heating so a whole property is brought up to a comfortable, efficient standard in one programme rather than piecemeal.
Where draught-proofing alone is not enough — a bedroom over a busy road, or a client determined to cut heat loss to a minimum — we can take the upgrade further. Slim-profile double-glazed units, some as thin as 11–14mm, fit into deepened original sashes or carefully matched new sashes, giving real thermal and acoustic improvement while keeping the slim sightlines and putty-line detail of a period window. From the pavement the difference is invisible.
Where a conservation officer requires the original glass to remain, or on a listed building, we instead fit discreet secondary glazing — a slim independent pane inside the existing window — which delivers excellent noise and draught reduction with no alteration to the historic fabric at all. We advise honestly on which route suits your property, your budget and your planning position before any commitment.
For homes on main roads, secondary glazing with a wide air gap is often the strongest performer for noise, outperforming sealed double-glazed units acoustically while leaving the original sash untouched. We will tell you which option best fits your particular problem.
Genuine restoration is joinery, not cosmetics. We renew only what has failed and keep everything sound.
Decayed cills, bottom rails and box sections are cut back to sound timber and matching new wood is scarfed and glued in — structurally invisible and far cheaper than replacing the whole window.
We use the same species and grain and machine new mouldings to match the existing sections exactly, so a repaired sash cannot be told from an original.
Perished cords are replaced with waxed sash line over serviced or new brass pulleys, and the cast-iron weights re-tied and balanced so the sash stays exactly where you leave it.
We free sashes glued shut by overpaint and swollen timber, re-set the runs and beads, and leave both sashes sliding smoothly with a light touch.
Our sash work draws on the same in-house carpentry and bespoke joinery teams that produce staircases, panelling and built-in furniture for our refurbishment projects — so the timber repairs to your windows are made to true cabinet-making standards.
A restoration is only as good as the finish that protects it. We treat decoration as part of the job, never an afterthought.
Failed and flaking paint is removed and bare or repaired timber treated, so the new finish bonds properly instead of trapping moisture under old layers.
We finish with a flexible, breathable paint system that moves with the timber and resists cracking — lasting years rather than flaking within a season like ordinary gloss.
Windows are finished to your scheme, inside and out, with crisp cut-lines to the glass. Our painting and decorating team can extend the same finish to the surrounding joinery.
The combination of sound timber, draught seals and a quality finish means a restored window needs only light maintenance for many years.
A great many of the homes we work on sit in conservation areas or are listed, and the rules around their windows catch owners out. On an unlisted house outside a conservation area, repairing or draught-proofing like-for-like is routine maintenance and needs no consent. In a conservation area, like-for-like repair is usually fine, but changing the glazing or the window profile can require permission. On a listed building, almost any alteration — including slim double glazing — needs listed building consent.
We deal with these constraints constantly and will tell you honestly which category your property falls into before any work is priced. Where consent is needed we can prepare and submit the application, drawing on our in-house architectural and planning support and our relationships with local conservation officers. The aim is always the same: the warmest, quietest, most durable window the rules will allow, achieved without putting your home’s heritage status at risk.
For flats and mansion blocks we coordinate with freeholders, managing agents and building surveyors, work to the block’s window specification, and keep a consistent appearance across the elevation — important where lease terms require uniform windows.
Sash restoration is far less disruptive than replacement — most of it happens at the window, and rooms are reinstated as we go.
A draught-proofing overhaul of one existing sash is typically a one-day visit. A full restoration of one window — splice repairs, re-cording, glazing and redecoration — usually runs two to three days.
We work room by room in a planned sequence so the house stays liveable, sequencing the elevations and giving you a firm programme and start date before we begin.
Most work happens at the window with the opening kept weather-tight. Floors, furniture and curtains are protected and the area cleaned down each day.
You deal with one team from survey to sign-off — the people who quoted the job are the people who carry it out and stand behind the guarantee.
We are a full design-and-build renovation company with in-house heritage joiners — not a window-replacement firm looking to sell you plastic units.
Our joiners restore period sashes week in, week out across London’s finest streets, and treat each window as a piece of joinery to be saved, not a unit to be swapped.
You get a written, fixed quotation after a real survey — no vague phone rates, no surprises, and an honest steer on repair versus replacement.
RIBA-chartered design partners, RICS surveying support, conservation-area and listed-building experience, and £10M insurance cover stand behind every project.
Directly-employed trades, a single point of contact and a 10-year workmanship guarantee — the same standard we bring to every refurbishment we deliver.
We restore sash windows throughout North, North West and Central London’s period neighbourhoods.
Our heritage joiners work across the areas we cover — from the Georgian and Victorian terraces of Hampstead, Belsize Park, Highgate, Primrose Hill and St John’s Wood to the stucco-fronted streets of Central London. Wherever your period home sits, we bring the same specialist sash restoration, draught-proofing and glazing expertise. For a wider project, our heritage restoration and period property restoration teams can take on the whole building, and our sash window restoration service folds neatly into a full refurbishment.
Sympathetic restoration of listed and period properties — brickwork, plaster, joinery and windows under one conservation-led contract.
Whole-house renovation of Georgian, Victorian and Edwardian homes that keeps original character while bringing comfort up to modern standards.
Hand-made staircases, panelling, doors and built-in furniture from the same in-house workshop that repairs your sashes.
Specialist preparation and long-life finishes for period joinery, inside and out, to complete the restored look.
Sash windows rarely fail overnight. Catching the early signs means a straightforward overhaul rather than a major repair — and a warmer, quieter home far sooner.
If a room is cold near the windows, the sashes rattle in the wind or you can feel air moving around the frame, the beads have worn and there is no draught seal. This is the most common reason owners call us — and the most cost-effective to put right.
A sash painted shut, jammed solid or one that slides down on its own points to bound timber, worn runs or a broken cord. Left alone, a window propped open with a book is a security and safety risk that only worsens.
Peeling paint, dark staining or timber that feels soft to a probe — usually on the cill or bottom rail — means water is getting in. Acted on early, it is a small splice repair; ignored, the decay spreads through the joint.
Persistent condensation, misting between panes or intrusive street noise are signs the glazing and seals are past their best — and a cue to consider draught-proofing, secondary glazing or slim double-glazed units.
A properly restored sash window needs very little upkeep. Once a year, slide both sashes fully and wipe the runs and brush seals clear of dust so they keep moving freely. Keep the paint film intact — touch in any chips promptly so water cannot reach the timber — and clear leaves and debris from the external cill and drainage so rain runs off rather than sitting on the wood. Avoid forcing a stiff sash; if one becomes hard to move it usually just needs the runs easing, which we are happy to do as a quick visit. Looked after this way, the timber, cords and finish we install will give you decades of smooth, draught-free service, and the window will continue to do justice to the period home it belongs to.
In the great majority of period homes, repair is both cheaper and better. Original Victorian and Georgian sashes were made from slow-grown, dense heart pine or oak that is far more durable than modern softwood, so even windows that look beyond saving are usually sound once the failed sections are spliced out. We replace only the timber that has actually decayed, re-cord the mechanism, draught-proof the whole window and redecorate — restoring it to better-than-new performance while keeping the original glass and joinery that give a period facade its character. Full replacement is recommended only where the boxes are structurally gone or a previous owner has already fitted poor-quality modern units.
Yes. We rout a discreet brush-pile seal into the staff bead, parting bead and meeting rails so it sits hidden within the window. From the room and from the street the window looks identical — there is no visible plastic trim — but rattle, draughts and the whistling you get on a windy night are eliminated, and the sashes run more smoothly than before. Draught-proofing typically cuts heat loss through the window markedly and is the single most cost-effective upgrade for a cold period room.
Original boxes can often take slim-profile double glazing — sealed units as thin as 11–14mm — into deepened or new sashes, giving a real thermal and acoustic improvement while keeping the slim sightlines and putty-line detail of a period window. Where the conservation officer requires the original glass to stay, we instead fit high-performance secondary glazing, or restore the existing single glazing and rely on draught-proofing. We advise on the right route for your property, budget and any planning constraints before any work starts.
On an unlisted house outside a conservation area, repairing or draught-proofing like-for-like is normally routine maintenance needing no consent. In a conservation area, like-for-like repair is usually fine but changing the glazing or profile can need permission. On a listed building, almost any alteration — including double glazing — needs listed building consent. We deal with conservation areas and listed buildings constantly, will tell you honestly which category your project falls into, and can prepare and submit the application where one is required.
A single window draught-proofed and overhauled in situ is typically a one-day job. A full restoration — splice repairs, re-cording, new cills or beads, double glazing and full redecoration — usually runs two to three days per window, and we work through a whole house in a planned sequence so rooms are reinstated as we go. We give you a firm programme before we start and protect floors, furniture and curtains throughout.
Sticking is almost always layers of old paint binding the sash to the frame, or swollen timber; rattling means worn beads and no draught seal; and a sash that drops shut has a broken cord or a weight that has come off its knot inside the box. All three are standard restoration work for us — we ease and re-balance the sashes, renew the cords over new or serviced pulleys, re-weight the box so the window stays exactly where you leave it, and draught-proof so the rattle never comes back.
Yes. We profile new glazing bars, beads and mouldings to match the existing sections exactly, using the same timber species and putty-line detail, so a repaired sash is indistinguishable from an untouched original. Where bars have been lost in a previous botched repair we can reinstate the correct Georgian or Victorian pattern from the surviving evidence on the rest of the elevation.
As a guide, draught-proofing and overhauling an existing sash typically starts from a few hundred pounds per window, while a full restoration with splice repairs, re-cording and redecoration is more, and adding slim double glazing more again — the exact figure depends on the size, condition and number of windows and whether access equipment is needed. Doing a whole elevation at once is more economical per window than one-offs. We give a fixed written quotation after surveying the actual windows, never a vague rate over the phone.
Yes — restoration includes full preparation and redecoration as standard. We burn or strip back failed paint, treat any bare or repaired timber, prime, and finish with a flexible microporous system that lets the timber breathe and lasts far longer than ordinary gloss. The result is a clean, even finish inside and out, colour-matched to your scheme, that protects the joinery for years rather than flaking within a season.
Both. We restore single problem windows, but most of our work is whole houses and mansion-block flats where every sash is overhauled, draught-proofed and redecorated as one coordinated project — which is more economical and gives a consistent finish across the elevation. For managed blocks and listed buildings we coordinate with surveyors, freeholders and conservation officers and work to the building’s specification.
“I would like to thank Ross and his team for their consistent commitment to quality and their unerring reliability. They delivered our property to specification and on time, proving to be an extremely effective, experienced, and proactive contractor.”
“We have worked with Ross and his company many times. They are extremely professional and hardworking individuals who can work under any circumstances. There was no variation to the works.”
Book a no-obligation consultation at our Finchley Road design studio or in your home. The first meeting is free, lasts 60–90 minutes, and concludes with an honest indication of feasibility, programme and budget band. No salespeople. No pressure.
Site visit · feasibility assessment · outline cost estimate · programme indication. No obligation. Saturday appointments available.