Stunning Accoya Sash Window Styles London 2026
Accoya Window Styles at a Glance
ExceptionalFinish
DimensionallyStable
NonToxic
MinimalMaintenance
SustainablySourced
Learn all about our Sash window styles.
Accoya is an ultra-high performance wood made from sustainably sourced timber and modified through a patented acetylation process, delivering unmatched durability and dimensional stability. It can be left natural or finished to suit any design, providing lasting performance in any climate or application. Backed by a 50-year above-ground warranty and 25 years in-ground or freshwater, Accoya is the trusted choice for exterior projects where longevity and low maintenance are key.
The Secret Behind ACCOYA®
Accoya isn't just wood. It's wood transformed.
Through a natural process called acetylation, we take fast-growing softwood and enhance it to perform like the finest hardwoods — without the drawbacks. The science is simple: by changing the way the wood interacts with water, we remove the root cause of swelling, shrinking, warping and rot.
The result is real, non-toxic wood that lasts for decades, stays dimensionally stable, and needs less maintenance. Even better, the process is circular: the only by-product is reused as vinegar for other industries.
Accoya sets a new standard in high-performance wood. Stable, durable, versatile and sustainable, it delivers exceptional results with no compromise — whether you're designing for today or building for the future.
Accoya delivers exceptional durability, backed by a 50-year warranty above ground and 25 years in-ground or freshwater, certified for use in termite zones, and proven to be 22 times more resistant than pine, with a service life of up to 80 years in real-world conditions.
Accoya comes from FSC®-certified forests, is one of the few building materials certified Cradle to Cradle® at the Gold level, and is non-toxic and 100% recyclable.
Accoya wood offers exceptional dimensional stability, swelling 3–4 times less than traditional timber while helping to keep paint looking great for decades after installation.
Accoya is the ultimate versatile substrate, trusted by craftsmen for its excellent machinability, improved density and hardness without compromising strength, and the flexibility to be left natural or finished to suit any design — delivering lasting performance in any climate or application.
High Performance Accoya Window Styles
From its superior insulation to its lasting good looks, Accoya wooden window frames outperform other woods and uPVC in every way. Not to mention being better for the environment and healthier for you. Whether you're looking for traditional wooden sash windows, stylish bay windows, practical casement windows or impressive architectural glazing — Accoya delivers on all fronts. See our Accoya window styles here.
Wooden window frame styles
Accoya wood is very versatile — ideal for many different types of windows to suit any home. Take a look at our wooden window frame styles.
Wooden Sash Windows
Whether you are looking to enhance your home's character or replace deteriorating timber, Accoya wood is the definitive solution for high-performance sash windows.
Accoya Sash Windows
Expertly designed and handcrafted by some of the UK's finest joiners, Accoya has emerged as the premier choice for timber sash windows nationwide. As a homeowner, you can select from a wide range of bespoke factory finishes; thanks to Accoya's unrivalled dimensional stability, these coatings adhere better and last significantly longer, keeping your sash windows looking pristine for years to come.
Its versatility makes it ideal for both traditional heritage restorations and sleek, contemporary joinery. As a homeowner, you can select from a wide array of bespoke factory finishes; thanks to Accoya's unrivaled dimensional stability, these coatings adhere better and last significantly longer, keeping your sash windows looking pristine for years to come.
UK tried and tested
For more than twenty years, Accoya wood has undergone rigorous testing by accredited institutions. The resulting data highlights its exceptional durability and superior performance, particularly when utilized for high-quality wooden windows.
Low maintenanceSave time and money by repainting every 10–12 years instead of every 3–5.
Highly stableYour sash windows will continue to open effortlessly all year round.
WarrantyAccoya wood warranty giving you peace of mind for decades to come.
Non toxicAccoya is natural wood, and so good for the home and the planet.
Timber Casement Windows
Maximum light and benefits of real wood without the drawbacks.
Accoya Casement Windows
Crafted by leading joiners across the UK, Accoya is the ideal timber for your new wood casement windows. Durable, stable and sustainable casement windows made from Accoya will out-perform all other wood species ensuring your windows open effortlessly all year round.
Low maintenanceAccoya timber casement windows have a 50 year wood warranty
Highly stableAccoya timber casement windows have a 50 year wood warranty
WarrantyBenefitting from a highly stable wood entails minimal on-going care with Accoya wood casement windows.
Sustainably sourcedAccoya wood is sustainably sourced, offering a lifetime's peace of mind for your casement windows.
Wooden Bay Windows
Enhance your outdoor views with bespoke, made-to-measure timber bay windows, precision-crafted by Golden Ratio Sash Windows & Doors to perfectly complement your home's unique architecture.
Accoya Bay Windows
Add that extra touch!
From simple to complex designs Accoya bay windows allow you to enjoy panoramic views for years to come.
With a range of custom designs and factory finishes Accoya's stability and durability benefits outweigh the competition.
What is a Bay window?
Bay windows are architecturally designed to protrude from the building's exterior, significantly increasing natural light and creating a sense of additional interior space.
A classic configuration features a large central picture window flanked by two smaller windows angled to connect the unit back to the main wall. However, these versatile features can be customized with multiple panes and various silhouettes, including elegant arcs or sharp, modern rectangles.
Highly stableAccoya wood is exceptionally stable, allowing coatings to adhere better, look more vibrant, and last significantly longer.
Low maintenanceAccoya timber bay windows are easy and hassle-free, saving time and money for the long-term.
WarrantyFor peace of mind Accoya bay windows come with a 50 year wood warranty.
Sustainably sourcedAll Accoya wood is sustainably sourced from certified forests.
Period Sash Window Styles
While originally crafted from timber using traditional joinery, modern sash windows can now replicate historical aesthetics with remarkable precision. Key "tell-tale" features of a heritage-style window include:
Edwardian Windows
Boasting a '6 panes over 2 panes' design that helps deliver the best of both worlds, Edwardian windows are ideal for properties dating from the early 20th century.
Victorian Windows
Remarkably distinctive thanks to the addition of run-through sash horns, windows present during the Victorian era favoured a two panel grid design on both the top and bottom panes.
Georgian Windows
Georgian sash windows feature a '6 panes over 6 panes' design, traditionally using astragal bars to hold together smaller squares of glass. Today this is used for decoration only.
Traditional window features
While originally crafted from timber using traditional joinery, modern sash windows can now replicate historical aesthetics with remarkable precision — even in uPVC. Key 'tell-tale' features of a heritage-style window include:
Aesthetic Finishes
Classic bevelled putty lines and period-appropriate ironmongery to maintain a timeless look.
Structural Character
Authentic run-through sash horns, traditional corner joins, and deep bottom rails that mirror original proportions.
Bespoke Craftsmanship
The ability to custom-order units that meet exact historical specifications for a seamless architectural fit.
Why We Only Use Accoya Timber
Let our experts help you find the perfect Accoya window style for your London home.
- Doesn't swell or shrink — open effortlessly year-round
- 50-year above-ground warranty
- Perfect for UK weather and heritage properties
- More stable than oak, hardwood or softwood
- Cradle-to-Cradle Gold certified — FSC timber
Recent Case Studies
Verified projects from our London customers — with photos and 5-star reviews.
Finsbury Park
Bespoke Timber Sash Window Installation
"Saved our original Victorian windows when others said replace. Beautiful workmanship — our sash windows look brand new."
Stoke Newington
Victorian Sash Window Restoration
"Draughts completely gone. Warm house for the first time in years. Fair price and they clearly know period properties inside out."
Central London
Edwardian Sash Window Replacement
"They completely replaced two windows in our Edwardian home. Friendly, communicative and done quickly — in just 2 days."
North London
Victorian Sash Window Installation
"The detailing is very well done and accentuates the property nicely. The whole front of the house looks much better as a result."
Hackney
Bespoke Sapele Timber Front Door
"The quality of the timber and workmanship is outstanding. Our new front door has completely transformed the look of the house."