Sash window specialists since 2008 · London
Sash window repair and reglazing with vacuum double glazing in London
We repair your original sashes and fit slim double glazing into them — in Georgian, Victorian and Edwardian homes across London.
- Warmer rooms, lower bills — slim double glazing in your existing sashes
- No more draughts or rattles — draught-proofing, new cords and weights
- Rot cut out, not painted over — replaced in rot-resistant Accoya timber
- Listed homes and conservation areas welcome — the look stays original
Free, no-obligation quote · minimum 5 windows · from £650 a window
Before After What customers say
Is this happening to your windows?
Old sash windows usually fail from the bottom up. The sill and the bottom rail of the sash take most of the rain, so that is where rot tends to start. Putty dries out and falls away. Cords snap, and the gaps around the sashes open up and let the cold in.
Rot keeps spreading if it’s left, but a rotten window rarely needs replacing. We cut out the soft timber and splice in new Accoya, fit new cords and weights, and draught-proof the sashes. If a room still feels cold after that, we can fit slim vacuum glazing into the same sashes.
Because the windows look the same afterwards, like-for-like repairs don’t need planning permission. That helps in areas like Kensington, Chelsea, Hampstead and Islington, where many houses are listed or in a conservation area.
Below are the common problems and what we do about each one.
Rotten sills
Rot cut out, new Accoya timber spliced in
Rotten beading
New staff and parting beads, with weather-stripping
Cold draughts
Draught-proofing seals around every sash
Rotten frames
Frames repaired in Accoya, with a 20-year guarantee
Cracked glass
New glass, or slim double glazing
High heating bills
Slim double glazing in your existing sashes
Loose or missing putty
Reglazed and sealed
Outside noise
Slim double glazing cuts the noise
Stuck or rattling sashes
New cords and rebalanced weights
Condensation
Slim double glazing and draught-proofing
BeforeAfterRestore or replace?
When wooden windows are weathered and damaged, replacing them can look like the only option. It isn’t: even badly decayed windows can be repaired and brought back to full working order.
- Costs less than new windowsRestoring is cheaper and quicker than having new timber windows made and fitted.
- Keeps your home’s characterYour original sashes, glazing bars and mouldings stay where they are.
- The greener choiceWindows you already have are kept in use instead of replaced.
Before and after: our work
Photos from our own jobs, taken before we started and after we finished. Tap a pair to see it larger.
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Rotten sill cut out and replaced
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Frames repaired, broken panes replaced with double glazing
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French doors repaired and double glazed
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A curved sash window sill rebuilt
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A sash window fully restored
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Bay window restored and double glazed
Two ways we fix them
Restoration and repair
We cut out the rot and splice in new Accoya timber, fit new cords and weights, free stuck sashes and fit draught-proofing seals. Your windows keep their original timber and look.
20-year guarantee on timber repairs
From £650 a window · typically £770–£910
How we repair sash windowsRestoration plus slim double glazing
Everything in the restoration and repair package, plus new glass. We take out the single panes and fit vacuum glazing only 8 mm thick into your original sashes. The frames stay, and so does the look.
15–25-year guarantee on the glazing, 20 years on the timber repairs
From £1,050 a window · typically £1,050–£1,550, the full restoration included
How double glazing your sashes worksMinimum order: 5 windows. See the full price guide.
How we repair sash windows in London
Weather wears older windows down: the wood rots, and the finish cracks and lets moisture in. We repair sash and casement windows, front and French doors, so they work and look as they should.
- Rot in frames and sashes repaired in Accoya and Tricoya timber
- New sash cords and rebalanced weights
- Stuck and painted-shut windows freed
- Cracked or broken glass replaced
- Draught-proofing seals around the whole window
- New locks and extra security
- Sashes adjusted to take new glazing units
Many of the houses we work on in London are period homes, like the West London house further down this page, with over 30 original box sash windows, casement windows and French doors. There we keep as much of the old timber as we can and replace only what has rotted.
20-year guarantee on every timber repair
BeforeAfterHow we double glaze existing sash windows in London
Vacuum double glazing is only 8 mm thick, so it fits the slim rebate of a period sash. It insulates as well as standard triple glazing.
No new windows and no bulky secondary glazing: we fit the vacuum units into your existing wooden sashes, so your double glazed sash windows keep their original look, Georgian bars included. The sashes get the full restoration at the same time: rot repairs, new cords and weights, and draught-proofing.
- Warmer rooms and lower heating bills
- Less outside noise
- Better security
- No more cold draughts
See how it works
Recent work
Swipe to see all six.
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Sash windows restoration in West London
A period house with over 30 original box sash windows, casement windows and French doors, rotten in many places after years of neglect. Rotten wood was replaced in Accoya and Tricoya, the sills were rebuilt and every window was draught-proofed.
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Sash windows restoration in Beaconsfield
Timber sash windows in a Georgian house in the heart of Beaconsfield, repaired and draught-proofed.
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Leaded windows double glazed
Casement and bay windows with diamond-pattern leaded top lights. We repaired the frames, fitted vacuum double glazing and recreated the diamond pattern on the new glass with lead strips.
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Georgian sash windows restored and reglazed in Colchester
Original single glazed Georgian sashes, repaired and double glazed to cut heat loss while keeping the house’s character.
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Reglazing wooden windows near Colchester
A listed period house being turned into flats. Replacing the windows wasn’t allowed, so we restored the original frames and reglazed them with double glazing.
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Double glazing retrofit of timber windows in Cambridge
Timber casement windows in a detached house, reglazed with vacuum double glazing instead of being replaced. Thermal photos taken before and after show the difference.
What happens after you get in touch
- 1
Send us photos
Email photos of your windows, with how many windows there are and your full address, to:
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We send you an estimate
A price estimate for your windows, usually within 15% of the final price, so you know where you stand before anyone visits.
- 3
We meet for the quote
We look at the windows with you, then email you the final quote within three days.
Where we work in London: many parts of London, though not all, so send your full address with your photos and we’ll confirm we can reach you. Around London we also cover Hertfordshire, Essex and Buckinghamshire.
Questions London homeowners ask
How much does it cost in London?
Restoring a sash window starts at £650, and an average-size sash usually costs £770–£910. With slim double glazing it starts at £1,050 a window, usually £1,050–£1,550, and that price includes the full restoration: rot repairs, new cords and weights, and draught-proofing. The minimum order is 5 windows.
Can you work on a listed building or in a conservation area?
Yes, we regularly do. Like-for-like timber repairs don’t need planning permission, because the windows look the same afterwards. Double glazing a Grade 2 listed building does need permission, so apply for it before any work starts. More on listed buildings.
My windows are rotten. Can you still double glaze them?
Yes. We repair the frames first: the rotten parts come out and new solid Accoya timber goes in, then the new glass is fitted.
How long does double glazing take?
The vacuum glass is made to order, and at the moment it takes 8–16 weeks from order to delivery. We fit it into your windows as soon as it arrives.
Do you take the windows away?
No. We do all the work on site, in our mobile workshop.
What does the 20-year guarantee cover?
All our Accoya and Tricoya timber repairs: if rot comes back in a part we repaired within 20 years, we come back and fix it free. The vacuum glazing has a 15–25-year guarantee.
Is there a minimum order?
Yes, 5 windows.