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The initial plan involved replacing all of the windows. Subsequently, TRC were commissioned to design and manufacture a bespoke sample window. This window was to match the existing ones, which included a metal insert in the opening casement.
However, after detailed consultations with the residents, Historic England, and the Planning Department, it was decided to retain and upgrade the windows. This decision was influenced by the Grade II listing and the fact that the windows are an integral part of the building’s structure. A full replacement would be extremely difficult and costly. Therefore, TRC was commissioned to undertake a pilot flat refurbishment scheme, which included the following:
The windows were then tested by BRE and the results where far better than expected and all stakeholders were delighted with the results.
Acoustic Performance
This image depicts an acoustic test in progress.
From the results of acoustic testing, the newer installed window system provides an increase in the acoustic performance by approximately +3 dB (33.7dB to 36.4dB) across the frequency range of interest (100 Hz to 3,15kHz) .
Airtightness
This image shows an air tightness test in progress.
The average air tightness results for the whole apartment are as follows:
This signifies a 40% improvement in the apartment’s overall air tightness.
The survey was conducted using an infrared camera in accordance with BS EN13187:1999 standards. The initial survey took place in February 2023. Yielding the results displayed in these images.
A second survey, focusing on the restored windows, was conducted in September 2023, which can be seen in the third picture below.
The improvement is evident in the before and after images following the installation of vacuum glazing and acoustic and weather seals. In these images, blue shading indicates colder areas, while yellow shading highlights warmer areas.
Owing to the significant improvements in acoustic performance, air tightness, and thermal efficiency, it has been decided to proceed with this refurbishment scheme. Planning permission has now been granted for the entire building, with the plan to extend the window restoration to all 140 flats over the next three years.