Sash Window Replacement London
When original timber sash windows are beyond economical repair, Restore My Window provides carefully made sash window replacement in London, manufactured to match the original design, proportions, glazing bars and period character of your property. Replacement is never our first recommendation. Wherever possible, we advise restoration. But where the existing timber is too decayed, badly repaired or no longer fit for purpose, a new timber sash window offers better performance, improved security, reduced draughts and a longer-lasting result.
We work on Georgian, Victorian and Edwardian properties across London, including conservation areas and listed buildings, where getting the specification and appearance right matters most.
Why Homeowners Choose Sash Window Replacement
A well-made replacement sash window can make a real difference to comfort, security and appearance. Homeowners tell us they value:
- Improved energy efficiency – new timber frames fitted with double glazing cut heat loss considerably compared with worn, single-glazed originals.
- Reduced draughts and noise – modern seals and tighter tolerances keep cold air and street noise out far more effectively than an old, shrunken frame.
- Better security – new sashes can be fitted with concealed sash stops and modern locking hardware from the outset.
- Lower maintenance – correctly primed, finished timber and new ironmongery need far less attention in the years immediately after installation.
- Improved appearance – damaged or heavily patched frames are replaced with crisp, properly proportioned joinery that lifts the whole façade.
When Is Sash Window Replacement Necessary?
Most timber sash windows can be brought back to full working order through careful sash window restoration. Timber is a remarkably resilient material when it has been looked after, and a frame that looks tired on the surface often has plenty of life left in its core structure. That said, there are circumstances where replacement genuinely is the better path forward.
Severe Timber Decay
Rot that has spread through the main structural sections of a frame, particularly the bottom rail, sill or pulley stiles, can sometimes go beyond what splicing or resin repair can sensibly address. We test timber with a moisture meter and a bradawl during survey to find out exactly how far decay has travelled. If more than around a third of a frame’s structural timber has failed, replacement usually offers better long-term value than repeated patch repairs.
Failed Previous Repairs
We’re regularly called to properties where a previous sash window repair, often using the wrong type of filler, an unsuitable timber species or poor jointing technique, has failed within a few years. Once a frame has been compromised by repeated bodged repairs, the surrounding timber is often weakened too. In these cases, a single well-made replacement sash or frame is more cost-effective than another short-lived repair.
Structural Damage to Frames and Sashes
Windows that have suffered impact damage, significant warping, or movement caused by building settlement sometimes can’t be brought back into true alignment through repair alone. If the frame itself has racked out of square, or a sash has split through a structural joint, replacement allows us to rebuild the opening correctly rather than working around a fundamentally compromised structure.
Improving Energy Efficiency
Some homeowners choose replacement not because the existing windows have failed, but because they want a meaningful step up in thermal performance. A single-glazed sash frame, however well restored, will never match the U-values of a purpose-built double glazed unit. If energy efficiency is the priority and the existing frames are tired enough that restoration would mean a major rebuild anyway, replacement with double glazing often makes more sense than restoration plus separate draught proofing work.
Our Sash Window Replacement Services
Every replacement project is built around the proportions, glazing pattern and timber profile of the original window, even when the original is no longer there to copy directly. We work from photographs, surviving neighbouring windows, or period-appropriate joinery patterns common to the property’s age and style.
Full Sash Window Replacement
Where the entire frame, both sashes, the cill and surrounding casing need replacing, we manufacture a complete new timber sash window built to the exact opening size. This is the right approach when decay or damage runs through the whole assembly rather than just the moving parts.
Replacement Sashes
Often it’s only the moving sashes, not the surrounding box frame, that need replacing. If the frame itself is sound, we can manufacture new top and bottom sashes to fit the existing box, which is a more economical option than a full frame replacement and keeps more of the original fabric of the building intact.
Timber Sash Window Replacement
We manufacture exclusively in timber, never uPVC, because timber is what conservation officers expect to see on period properties, and because a well-specified hardwood or engineered softwood frame will comfortably outlast a plastic equivalent. We typically use Accoyed softwood or European oak depending on the property and budget.
Double Glazed Sash Window Replacement
For homeowners prioritising thermal performance and noise reduction, we offer a wide range of double glazed units designed to sit within traditional glazing bar widths, so the window keeps its historic appearance from the street while performing far better than single glazing. This is one of the most requested upgrades we install across London’s period housing stock.
Box Sash Window Replacement
Traditional box sash construction, with its concealed weights and pulleys running on cords or chains, is at the heart of how a sash window should look and feel. We replicate the box frame construction faithfully, so the new window opens, balances and sounds exactly as a genuine period sash window should.
Our repair service addresses these issues individually, allowing us to restore damaged timber without unnecessarily replacing the entire window. Whether your property has localised decay, damaged joints or worn timber sections, we use proven repair techniques to preserve as much of the original material as possible while restoring performance and appearance.
By focusing on repairing rather than replacing original timber wherever practical, homeowners can retain the character of their period property while extending the life of their existing sash windows.
Replacement vs Restoration – Which Is Right for Your Windows?
This is the question we're asked most often, and it deserves an honest answer rather than a sales pitch. The right choice depends on the condition of the timber, the importance of retaining original fabric, your budget, and what you want the windows to do for you going forward.
When Restoration Is Recommended
If the structural timber is sound and the issues are limited to surface decay, failed paintwork, worn cords, draughts or stiff operation, timber window restoration is almost always our recommendation. It costs less, retains more of the building's original character, and is generally favoured by conservation officers where a property sits within a conservation area or carries listed status.
When Replacement Is the Better Long-Term Solution
Replacement earns its place when the timber has failed structurally, when repeated repairs have already been tried unsuccessfully, or when a homeowner has a clear priority, usually thermal performance or sound insulation, that restoration alone can't fully deliver. It's also sometimes the more sensible option financially: extensive repair across multiple compromised areas of a single frame can occasionally cost close to what a quality wooden window replacement would, without the same guaranteed lifespan.
Balancing Cost, Appearance and Performance
We talk homeowners through this trade-off honestly at survey stage. Appearance from the street, especially on a listed building or within a conservation area, often weighs heavily, and our replacement joinery is built to match the original sightlines so the change is invisible from outside. Performance gains from double glazing are real but come at a higher upfront cost than restoration. Cost-wise, restoration is typically less expensive per window, but a well-built replacement should need very little maintenance for decades, which is worth factoring into the comparison.
| Factor | Restoration | Replacement |
|---|---|---|
| Cost | Lower | Higher |
| Original Character | Excellent | Good |
| Energy Efficiency | Good | Excellent |
| Lifespan | Depends on condition | Excellent |
As a general rule, restoration wins on cost and retained character, while replacement wins on energy efficiency and predictable lifespan. Where a frame is still structurally sound, this usually tips the decision towards restoration, but if the timber has already failed, replacement's lifespan advantage becomes the deciding factor.
Traditional Timber Sash Window Replacements
Maintaining Period Character
A replacement sash window should be indistinguishable from the original at a glance. We pay close attention to glazing bar widths, horn details, putty lines and timber sections, because these small details are what separate a genuinely period-appropriate window from a generic modern joinery product.
Suitable for Conservation Areas
Many London boroughs require like-for-like replacement on properties within conservation areas, and listed buildings have additional consent requirements. We have experience preparing the kind of detailed specifications that planning officers and conservation teams expect to see, covering timber species, glazing bar profile, putty versus bead glazing, and finish.
Matching Existing Architectural Features
Where some original windows survive elsewhere on the property, we use them as the template for replacements, matching horn profiles, meeting rail depth and astragal bar widths so the new windows sit comfortably alongside the old.
Sash Window Replacement Cost
The cost of replacement sash windows varies from property to property, since no two openings or specifications are quite the same.
Factors That Affect Cost
Cost depends on the size of each opening, whether you need a full frame or just replacement sashes, the timber species specified, single or double glazing, and any additional detailing such as horns or decorative glazing bars.
Single Window vs Multiple Windows
Replacing several windows in one visit generally brings the cost per window down, since survey, setup and access costs are shared across the project rather than repeated for each individual window.
Timber and Glazing Options
Softwood frames cost less than hardwood, and single glazing costs less than double glazing, but the right specification depends on the property’s requirements rather than upfront price alone. We’ll talk you through the genuine trade-offs at survey stage.
Requesting a Free Estimate
Because every property and every window is different, we don’t publish fixed price lists. The most accurate way to understand cost for your specific windows is a survey, which we provide free of charge and without obligation.
Sash Window Replacement for London Period Properties
London's housing stock spans several distinct architectural periods, and each comes with its own joinery conventions and, often, its own planning considerations. We tailor every wooden sash window replacement to suit the specific period and borough requirements of the property in question.
Georgian Properties
Georgian homes typically feature narrow glazing bars, six-over-six or eight-over-eight pane arrangements, and relatively flat sash horns. Replacement windows on these properties need fine glazing bar sections to avoid looking heavy-handed against the original proportions.
Victorian Terraces
Victorian terraces, by far the most common period property type across London, often have two-over-two sashes with horns, sometimes alongside margin lights or decorative coloured glass in hallway windows. We replicate these details closely, since they're frequently what gives a Victorian terrace its street-level character.
Edwardian Houses
Edwardian properties tend towards larger panes with simpler glazing patterns, sometimes combined with leaded upper lights. Replacement specifications for these properties usually focus on getting proportion and sightlines right rather than replicating intricate glazing bar arrangements.
Conservation Areas
Where a property sits within a conservation area, the local authority will usually expect any replacement to match the appearance of the original in materials, colour and glazing pattern, even if exact like-for-like replication isn't a formal requirement.
Borough Planning
Borough requirements vary, and some conservation areas have specific Article 4 Directions removing permitted development rights entirely, meaning planning permission is required. We factor these rules into our specification process from the outset.
Upgrade Your Original Sash Windows Today
Stop living with rattling frames, cold draughts, and windows that compromise your heating bill. Our London sash window replacement specialists preserve the historical architecture of your property while delivering modern thermal efficiency.
Benefits of Replacing Sash Windows
Improved Thermal Efficiency
Beyond the glazing itself, new frames are built tighter and truer than an old box sash that has shrunk, swollen or warped over decades. Combined with double glazing, this closes the small gaps around the sash that account for much of the heat loss in older timber windows, on top of the improvement the glazing alone provides.
Reduced Draughts and Noise
New seals, brush strips and tighter meeting rail tolerances make a measurable difference to draughts, and the same close fit reduces airborne noise transfer, which is particularly noticeable on properties facing busier roads.
Enhanced Security
We specify modern security hardware, including concealed sash stops and shoot bolts, that simply wasn't available when most period sash windows were originally built. This is fitted from the outset rather than retrofitted, so it integrates cleanly with the new frame.
Lower Maintenance Requirements
A correctly primed and finished new frame, paired with new ironmongery and weatherproofing, typically needs only routine repainting for its first several years, rather than the ongoing patch repairs that an older, failing frame often demands.
Our Sash Window Replacement Process
Initial Survey and Assessment
We visit the property to inspect every window in question, test the timber condition, take detailed measurements and discuss your priorities, whether that's matching appearance, improving thermal performance, or working within a particular budget.
Measuring and Manufacturing
Once specifications are agreed, including timber species, glazing type and finish, we manufacture each window to the exact dimensions of its opening. No two period properties are identical, so off-the-shelf sizing has no place in this work.
Removal of Existing Windows
Our team removes the old frame carefully, taking care to protect surrounding plaster, brickwork and interior decoration, and disposes of the old materials responsibly.
Installation and Finishing
New frames are fitted, weighted and balanced, then finished on site to match the surrounding woodwork. We can also arrange ongoing window painting services to keep new and existing timber looking consistent across the whole property.
Free Quotation
Frequently Asked Questions
Costs vary considerably depending on window size, timber species, whether you need a full frame or just replacement sashes, and whether you choose single or double glazing. Properties in conservation areas may also need specific detailing to satisfy planning requirements, which can affect the specification and cost. Rather than quoting a generic figure that wouldn’t reflect your actual windows, we provide a free, no-obligation survey so we can give you an accurate estimate based on the real condition and dimensions of your frames. Most homeowners find it useful to get this figure before deciding between repair and replacement, since the comparison only makes sense once both options have been properly costed against your specific windows.
Repair is almost always cheaper than full replacement when the underlying timber is structurally sound, since you’re addressing specific defects rather than manufacturing an entirely new window. However, if a frame needs extensive repair across multiple areas, or has already had previous repairs fail, the cumulative cost of ongoing repair work can approach what a single well-built replacement would cost, without offering the same guaranteed lifespan. We always assess the actual condition of your timber before recommending one route over the other, since guessing without a proper survey rarely gives homeowners an accurate picture.
Yes. We manufacture double glazed sash windows from a wide range of units designed to fit within traditional glazing bar widths, so the window retains its period appearance from the street while delivering significantly better thermal and acoustic performance than single glazing. This is one of the most popular upgrades among London homeowners looking to reduce heating costs and outside noise without altering the character of their property. We can advise on the most appropriate glazing specification for listed buildings and conservation area properties, where there may be specific requirements around appearance and glazing bar profile.
This depends on whether your property is listed, sits within a conservation area, or is a standard unlisted property. Listed buildings generally require listed building consent for any window replacement, and conservation areas often require like-for-like replacement in terms of materials and appearance. Standard unlisted properties outside conservation areas usually don’t need planning permission for sash window replacement, provided the new windows match the style of the originals. We can advise on the requirements specific to your property and borough during the survey, and help prepare the kind of specification documentation that planning and conservation teams typically expect to see.
Yes, matching existing windows is central to how we approach every replacement project. We take detailed measurements and reference any surviving original windows on the property to match glazing bar width, horn detailing, meeting rail depth and overall proportions. Where no original examples remain, we draw on period-appropriate joinery patterns typical of the property’s age and architectural style. The result is a replacement window that looks consistent with the rest of the property and satisfies the expectations of conservation officers where relevant.
Timescales depend on the number of windows involved and the complexity of the specification. Manufacturing typically takes several weeks once a survey and order are confirmed, since each window is built individually rather than taken from stock. On-site installation itself is usually completed within a day or two per window, depending on access and any making-good required to surrounding plaster or brickwork. We’ll give you a clear timeline specific to your project once survey and specification are finalised.
Our Latest Reviews
Stuart Wolfe-Murray
Restore my window it must stand for Absolutely Perfect Solutions! 🙂 Very pleased with the work the guys did for me. Super professional, communication was prompt and easy, they arrived on time and completed the work to a very high standard.
Russ
We couldn't be more pleased with our newly replaced windows; they look, and work, amazing. You were courteous, professional and worked incredibly hard. We wouldn't hesitate to recommend you, and will certainly give you a call if we need any similar joinery in the future. A definite 5 stars!
Monika Kania
I had my old sash windows replaced and my whole flat decorated with Restore My Window. I am very happy with the result. The guy from the team was very friendly, punctual and tidy. Excellent quality and great value!
Steven Brown
Andrea and his team carried out excellent refurbishment work to my wooden sash windows. I honestly thought they were beyond repair but after just a few days they are now as good as new. Very professional, very clean and tidy, very friendly service. HIGHLY RECOMMENDED!
Carolina Skowron
Excellent service from initial quotes to fitting. The team were super helpful, went out of their way to make sure things went smoothly. The owner is very friendly and approachable, kept us updated on progress throughout. Very happy with the professional service and the final results.
Marina Petrova
Andrea and his team did an excellent job! They were super friendly and helpful throughout and my windows look beautiful. I would highly recommend them especially if there is more gnarly restoration work to do.
Rosse Sheldon
A punctual, efficient and professional team, producing work to a high standard. Transformed a shambolic decaying period window into a beautiful eye-catching focal point. Left the site completely tidy. Highly recommended
Kasia
Great services. The guys that came to replace the windows were really polite and tidy. The windows themselves look amazing.
Steve
This was the first time I have used the company and they did not disappoint. 3 new wooden sash windows were replaced. The guys were friendly, considerate and very efficient. Quality workmanship which I can happily recommend.