Sherborne House, 119-121 Cannon Street, EC4 is a multi-let property situated in the heart of London’s financial district Cannon Street. Clad in Portland stone, this historic office building has been the subject of a recent transformation and received an internal and external make-over. The design for the office space on the second floor was entirely open plan and a major issue was the ingress of the outside noise emanating from the hustle and bustle of one of London’s busiest roads.   Twenty1 Construction contacted Selectaglaze, to provide them with a solution to improve the acoustic insulation of the existing primary windows, which could not be replaced. All the original openings were remodelled including the relining of the reveals and removal of the old heating system. On completion of the building works a survey was undertaken for 17 new secondary glazing units from the slimline range. Both Series 10 horizontal sliding and Series 20 vertical sliding units were used. Each was surveyed and manufactured for a specific opening to ensure a perfect fit to achieve the desired performance.