Bespoke Accoya Timber Windows –
Built to Last 50+ Years
- 50 Year Lifespan
- FSC Certified Timber
- Low Maintenance
Accoya Window Styles at a Glance
Learn all about our Sash window styles.
Accoya is an ultra-high performance wood made from sustainably sourced timberand modified through a patented acetylation process, delivering unmatched durabilityand dimensional stability. Accoya can be left natural or finished to suit any design,providing lasting performance in any climate or application. Backed by a 50-yearabove-ground warranty and 25 years in-ground or freshwater, Accoya is the trustedchoice 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 andenhance it to perform like the finest hardwoods—without the drawbacks. The scienceis simple: by changing the way the wood interacts with water, we remove the rootcause 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 resultswith no compromise – whether you’re designing for today orbuilding for the future.
Accoya delivers exceptional durability, backed by a 50-year warranty above groundand 25 years in ground or freshwater, certified for use in termite zones, and provento be 22 times more resistant than pine, with a service life of up to 60 years in real-world conditions.
Accoya comes from FSC® certified forests, is one of the few building materialscertified 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 thantraditional wood to keep projects looking great for decades after installation.
Accoya is the ultimate versatile substrate, trusted by craftsmen for its excellentmachinability, improved density and hardness without compromising strength, andthe flexibility to be left natural or finished to suit any design — delivering lastingperformance in any climate or application.
High Performance Accoya Window Styles
Quality where it counts 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.
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
Low maintenance
Highly stable
Warranty
Non toxic
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 maintenance
Accoya timber casement windows have a 50 year wood warranty
Highly stable
Warranty
Non toxic
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 stable
Low maintenance
Non toxic
Warranty
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
Victorian Windows
Georgian Windows
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:
Structural Character: Authentic run-through sash horns, traditional corner joins, and deep bottom rails that mirror original proportions.
Aesthetic Finishes: Classic bevelled putty lines and period-appropriate ironmongery to maintain a timeless look.
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:
- Doesn't swell or strink
- 50-year above ground warranty
- Perfect for UK weather
- More stable than oak or hardwood
If you are unsure which era your property belongs to, our expert guide: sash windows in London conservation areas 2026 provides the essential context for a successful project.
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