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Higher Window performance of Box Sash Windows

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Salisbury Joinery is proud to report that its high-performance Box Sash Window has achieved an even higher rating of weather performance following stringent independent tests. Alongside our existing certification to British BS6375-1 and EN14351-1 European Weather Performance Standards, certification to the Overall UK Exposure Category 2000 provides even further reassurance in the year-round weather performance, strength and durability of our windows. 

Stringent Testing

Sash Window Weather Test

Our windows are independently tested by specialists, ERC Testing Ltd in conjunction with TÜV Rheinland Nederland B.V, a division of one of the largest certification and test bodies in the world.

For a window to be included in the exposure category 2000 the test pressure standards in BS 6375 for air permeability, water-tightness, and wind resistance must be attained or exceeded. The tests involved the windows being bolted to a professional test rig, with performance measured across the whole of the window construction through highly accurate computer monitoring.

The following test results were achieved:

Resistance to Wind Load test (EN12210) to a value of 1200Pa (Pascals) Class 3C. Water Tightness (EN12208) to a value of 450Pa Class 8A and Air Permeability (EN12207) met the required standard of 300pa, Class 2.

EN14351_Test_Table 2023

Our certification permits the use of timbers with density of over 510kg/M³, such as Accoya, Sapele and European Oak which great improves durability. Accoya uses cutting-edge technology to resist rot, prevent water ingression and avoid the cracking associated with changes in weather temperature and humidity. Its remarkable performance properties are ideally suited to use on external windows and doors.

Choice of Window Specification

Windows up to 1400 x 2200 mm are certified with standard cavity double glazing. Both our traditional box sash windows, operated through weights and pulleys, as well as our spring-balance sash windows are covered.

Traditional timber sash windows are suited to heritage and conservation properties and use cords, weights and pulleys to counterbalance the sashes with the weights discreetly hidden in the boxes on either side. Spring-balance sash windows on the other hand, offer a modern alternative to the weights-based system that feature spring-loaded mechanisms on each side of the sashes. They have the advantage of a smaller rebate and boxes are not required, so they are particularly suited to properties free of conservation constraints but where a stylish traditional appearance is desired.

Half-Way House Sash Windows 2

Dual Certification

The design of our Sash Windows and their proven weather performance offers the potential of a longer product lifespan and reduced maintenance for properties owners. The certification document for this product is available now to download. In addition our high performance range is also certified to PAS24:2016 security standards and offers high levels of energy efficiency. We continue to invest in the development of our windows, doors and staircase ranges to lead the market and meet customer needs. 

Salisbury Joinery has hand-crafted bespoke sash windows for period homes and new developments for over 40 years, so has the experience to provide the right advice. Working with local builders and developers across the South, the company has built an enviable reputation for the quality of its workmanship and responsiveness of its service. 


Listed Building Windows and Doors Guide