Acoustic Windows Keep the Peace at former US embassy

When it comes to luxury redevelopments, they don’t come much more complex than former US Embassy building No 1 Grosvenor Square with its rebuilt stone façade, SFS on springs and listed building status. The design and installation of sympathetic timber windows and doors for such a project is far from straight forward which means it is ideal for George Barnsdale.

Having seen the work Barnsdales carried out at 20 Grosvenor Square, Lodha decided from a very early stage that the Lincolnshire based manufacturer would supply the fenestration for their own “presidential”project.

Set in the heart of Mayfair with its replica Oval Office, No 1 Grosvenor Square is a prestigious development of high end luxury apartments. One of the key requirements was to mitigate for the underground noise using a complex internal rebuild on giant springs to absorb vibration and sound.

One of the biggest challenges the Barnsdale team had to overcome was installing the windows before the external envelope was completed. This meant that windows were effectively located mid air using gridlines. This was a highly complex process as window one might be 300mm in front of gridline while window 2 was 1500mm. The result of this was nearly 70 interface drawings!

Commenting Tom Wright, MD at George Barnsdale said “Whilst the SFS was designed to move, the external walls of the building (rebuilt brick and stone façade) remained static so the technical challenge of installing windows in this scenario where there was marked differential movement was considerable. We worked closely with Illbruck to develop and interface that would work with their SFS/façade detail taking into account waterproofing, acoustic and weather performance.”

Early involvement enabled George Barnsdale to provide a detailed programme through the tender stage to ensure that the contractor had a good understanding of the critical timeframes and could make the right decisions at the right time. As time progressed, such collaboration with the architect and the wider project team proved invaluable to the process of overcoming issues as soon as they arose minimising disruption.

The windows themselves were specified to meet the octave specific noise reduction and the whole window’s acoustic performance was validated not just the centre pane glazing data. “Unlike other manufacturers, we don’t just rely on glass manufacturer data because as soon as glazing is put into a frame, it’s performance is affected. Instead we have a vast array of tested technical and acoustic data as well as the installation detail to ensure accurate calculation of acoustic and thermal  performance of the entire window.” Tom continued.

Alongside ultra high acoustic performance, the project demanded a very high level of security with integrated security contacts and fitted custom handles to the doors.