The Sash Window Workshop, a leading British manufacturer of high-performance timber windows, has announced that its latest Product Innovation box sash window system has successfully passed independent PAS 24 testing, the recognised UK benchmark for enhanced security performance in newbuild and refurbishment projects meaning the product is Part Q compliant.
The achievement marks a significant milestone in the company’s multiphase research and development programme, initiated in 2025 to deliver a high security, design led sash window specifically engineered for commercial schemes, newbuild residential developments and architect specified projects.
Over the past six months, The Sash Window Workshop’s production and design teams have collaborated to engineer, refine and test a dedicated Part Q compliant box sash window. Working with a UKAS accredited test house, the team developed multiple prototypes, incorporating structural enhancements following early-stage evaluation. The final preproduction design, known internally as V2, was submitted for full certification testing. What sets the box sash window apart from our current design is that the top sash is now opening and the maximum window size has now increased to 1.4m wide by 2.3m high.
The rigorous PAS 24 assessment subjects windows to a series of simulated breaking attempts. The test batch included five full-size box sash windows, with the largest measuring 2.3m in height, ensuring the system performs consistently across a range of commercial-scale apertures.
“Achieving PAS 24 performance has been a key objective within our Product Innovation roadmap,” said Richard Dollar, MD at The Sash Window Workshop. “Developers and architects are increasingly required to meet tighter security and compliance standards, particularly across high end residential and mixed use schemes. Our new PAS 24-tested sash window provides robust security performance while preserving the classic timber aesthetic demanded by design conscious projects.”
With the test programme now successfully completed, The Sash Window Workshop will be sharing technical updates with its network of developers, contractors and architectural practices, ahead of general specification availability.
Professionals planning upcoming 2026 projects that require PAS 24 compliant sash windows are invited to contact the commercial team on info@sashwindow.com for more information.
Key Features & Benefits
- PAS 24 certified for enhanced security performance
- Designed for newbuild and commercial applications, including high end residential schemes‑build and commercial applications‑end residential schemes
- UKAS accredited testing ensures verified, independent performance accredited testing‑accredited testing
- Engineered for design flexibility, preserving traditional sash aesthetics
- Robust performance across large window sizes, up to 2.5m in height
- Optimised for compliance with modern building and security regulations
