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From Anatomy to Architecture: Optimising Sash Window Design for complex projects with TRC Contracts

From Anatomy to Architecture: Optimising Sash Window Design for complex projects with TRC Contracts
From Anatomy to Architecture: Optimising Sash Window Design for complex projects with TRC Contracts
Wed Apr 17

For architects specialising in heritage or high-performance buildings, sash windows are a design element that demands both aesthetic and functional excellence.

TRC Contracts understands the intricacies of sash window design and offers a comprehensive service to optimise window solutions for complex architectural projects.

This blog delves into the anatomy of a sash window, exploring the individual parts that contribute to its enduring popularity.

We then explore TRC’s design service, highlighting the benefits of collaborating with our team to achieve exceptional results in your projects.

The anatomy of sash windows

A sash window is an elegant and practical marvel comprised of several key components, each playing a vital role in its operation and visual appeal. Understanding these parts is crucial for informed design decisions:

Parting bead: These narrow strips separate the upper and lower sashes, allowing smooth sliding movement.

Staff bead: Framing the sash box on the inside, the staff bead holds the sashes in place. Removing it requires specialist knowledge to avoid damage.

Sash box: This is the overall window frame that surrounds the opening and incorporates the external window sill.

Top, bottom & mid-rail: The horizontal timber sections of each sash frame are called rails. The top and bottom rails meet at the mid-rail. The bottom rail, particularly vulnerable to weather damage, is a common area for rot to develop.

Glazing bars: A characteristic feature of Georgian homes, glazing bars are the small timber pieces that divide the glazed sash into sections. Configurations vary, with Georgian windows often referred to by the number of panes, such as “6 over 6” or “9 over 9.” Victorian sashes typically lack glazing bars and have a single large pane per sash (“1 over 1”).

Sash cord & pulley: Traditionally made of braided cotton or jute with a wax finish, sash cords run over pulleys, enabling smooth sash movement.

Sash removal system (SRS): A unique system developed by TRC, the SRS facilitates future maintenance by allowing for internal sash removal without major disruption.

Sash weights: Hidden within the box frame alongside the pulley system, sash weights  counterbalance the sashes for effortless operation.

Sashes: The heart of the window, sashes are the moveable panels (single or double hung) that slide vertically within the window frame to open and close.

Sill: The external window sill bears the brunt of the weather, making it susceptible to rot. During window renovation, TRC treats or replaces rotten timber, ensuring structural integrity.

Understanding these individual parts empowers architects to make informed decisions about design, material selection, and overall window performance.

TRC Contracts: Design partnership for exceptional sash windows

At TRC Contracts, we believe that exceptional sash windows are the result of a collaborative design process. We offer a comprehensive service tailored to the specific requirements of your project.

Unparalleled design expertise

Our team possesses in-depth knowledge of sash window anatomy, historic styles, and modern performance considerations. We work closely with architects to ensure the design seamlessly integrates with the overall architectural vision.

Standard range & bespoke design

We offer a versatile range of standard sash window styles meticulously crafted with high-quality timber, finishes, glazing options, and ironmongery. Additionally, our in-house design service caters to bespoke projects, meticulously replicating historic features or creating unique contemporary designs.

Performance engineering

Sash windows are not just about aesthetics. We incorporate high-performance features such as draught-proofing systems and energy-efficient glazing to meet project-specific thermal and acoustic requirements. Our standard window range is rigorously tested by independent UKAS accredited bodies, ensuring exceptional performance.

Experience with prestigious projects

TRC’s windows grace some of the UK’s most iconic buildings, including Somerset House, The Old War Office, and the Blackpool Tower Ballroom. This experience translates into a deep understanding of complex project demands and meticulous attention to detail.

By partnering with TRC Contracts, architects gain access to a wealth of knowledge, exceptional craftsmanship, and a commitment to delivering high-performance sash windows that transform the aesthetics and functionality of any architectural project.

How can TRC Contracts help you?

Sash windows are a timeless design element that demands careful consideration, particularly in complex architectural projects.

TRC Contracts’ comprehensive design service, combined with our in-depth knowledge of sash window anatomy, performance optimisation, and heritage preservation, empowers architects to achieve exceptional results.

We encourage you to contact TRC Contracts today to discuss your project requirements. Our team of specialists is ready to collaborate with you to design and manufacture beautiful, high-performing sash windows that become a cornerstone of your architectural vision.

As a trusted and reputable supplier, TRC Contracts is proud to be a member of NBS Source. Our profile on NBS Source provides architects with easy access to detailed information about our products and services, making it even more convenient for you to explore the range of sash windows we offer.

Visit our profile on NBS Source today to learn more about how TRC Contracts can meet your project requirements and deliver exceptional results.

Additional Resources

Heritage Window Range

Traditional Window Range

Window Restoration

Project Management


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