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Timber Sash Windows

Sash windows are one of the most distinctive and enduring features of British architecture. Their graceful symmetry and smooth vertical motion have defined the façades of homes for centuries, from elegant Georgian terraces to refined Victorian villas and contemporary townhouses.

We craft bespoke timber sash windows that preserve this timeless charm while delivering the efficiency, security, and sustainability expected of modern homes. Designed and built in Cornwall, they combine traditional joinery with cutting-edge performance to create installations that look exceptional and last for generations.

Whether you’re restoring a listed property or designing a new build with classic appeal, Nine Zero brings heritage design and modern innovation together in perfect harmony.

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Sash window styles at Nine Zero

We offer two distinct sash window styles, each handcrafted to suit different architectural needs and aesthetic preferences.

Timber box sash windows

Our box sash windows capture the beauty of traditional sash design, featuring a cords-and-weights system concealed within a timber frame. Perfect for Georgian, Victorian, and Edwardian properties, these windows bring authenticity and grace to period restorations and heritage buildings.

With precise joinery and tailored detailing, each window is built to replicate the elegance of original features while meeting the performance standards of the 21st century.

Timber box sash windows

Timber spring sash windows

Our spring sash windows offer a contemporary take on the classic design, using a concealed spring balance system for smoother operation and a slimmer frame profile. Ideal for modern homes and refined renovations, they provide the same charm as traditional sashes but with a cleaner, more streamlined finish.

Engineered for efficiency, ease of use, and exceptional longevity, they represent the evolution of heritage design into modern craftsmanship.

Timber spring sash windows

What are sash windows?

A sash window is made from one or more movable panels, known as “sashes,” that slide vertically to open and close. This elegant design enables smooth ventilation, optimal space efficiency, and a clean, balanced appearance that complements both historic and contemporary architecture.

Unlike hinged casement windows, sash windows don’t swing outward or inward. Instead, they glide effortlessly within their frame, offering both form and function. The result is a window style that maximises light and airflow while maintaining refined architectural lines.

Learn more about sash windows and how they work in our guide.

What are sash windows?
Sash Window Nine Zero
Sash Window Nine Zero

Built for performance and designed for beauty

Behind every sash window lies a dedication to craftsmanship and innovation. Our designs are tested to meet BS 6375:2015 Parts 1 and 2, ensuring exceptional weather resistance and performance in real UK conditions.

Advanced glazing and sealing technology provide outstanding thermal efficiency, with U-values as low as 1.0 W/m²K. Combined with discreet multi-point locking and high-quality finishes, our windows deliver all the comfort, safety, and reliability you expect, wrapped in timeless elegance.

Every sash is made to order, measured, and finished with care to suit your project perfectly.

Our sustainable timber

Our glazing options

We offer a range of glazing options, from slimline Heritage double glazing ideal for listed and conservation properties, to high-performance double or triple glazing for contemporary homes seeking superior insulation and acoustic comfort.

Our glazing systems reduce heat loss, minimise condensation, and improve soundproofing, helping to keep your home quieter, warmer, and more energy-efficient without compromising on authenticity or craftsmanship.

Warranty

Why choose Nine Zero for your sash windows?

Sustainably sourced timber

We use FSC-certified timber and recycle all waste, reflecting our commitment to environmental responsibility without compromise on quality.

A collaborative approach

We work closely with developers, architects, and installers to ensure a seamless process.

Industry-Leading guarantees

All our sash windows are backed by a warranty of up to 30 years on timber and 10 years of cover on glazing, workmanship, and paint finishes, giving you peace of mind that your investment will stand the test of time.

Start your sash window project with Nine Zero

Whether you’re restoring a Georgian townhouse, replacing tired double-glazed windows in a Victorian villa, or designing a new property with period charm, Nine Zero brings bespoke craftsmanship and modern performance together seamlessly.

Our experts will guide you through every stage to ensure a smooth, transparent experience tailored to your goals. Contact us today to discuss your project, request a quote, or explore how bespoke timber sash windows can transform almost any space.

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FAQs

Are timber sash windows energy efficient?

Yes. Modern timber sash windows are highly energy efficient, especially when fitted with double glazing and precision draught-proofing. We use engineered timber and advanced sealing systems to achieve this, helping to reduce energy bills while keeping homes warm and comfortable.

Can sash windows be installed in listed buildings or conservation areas?

They can, and Nine Zero’s expertise makes the process straightforward. We work closely with you to ensure your design meets planning and conservation requirements. Our Heritage Range includes authentic profiles, slimline glazing, and traditional joinery options designed specifically for sensitive restorations.

How long do timber sash windows last?

With proper care, high-quality timber sash windows can last for decades, often exceeding 50 years. All of our products are backed by industry-leading guarantees: up to 30 years on timber and 10 years on glazing, paint finishes, and workmanship, giving you confidence in their long-term durability.

What’s the difference between box sash and spring sash windows?

The main difference lies in the mechanism. Box sash windows use a traditional cords-and-weights system hidden within a timber frame, while spring sash windows feature a modern concealed spring balance for smoother operation and slimmer profiles.

How long does it take for your sash windows to arrive?

Once your design is approved, we typically craft and deliver bespoke sash windows in around 6–8 weeks.

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Request a brochure

To explore our range of sustainable timber windows and doors and imagine the possibilities for your project, request a Nine Zero brochure by contacting our team today.