County Hall, Norwich

480 unitised window cassettes for the refurbishment works at Norfolk County Hall were manufactured by Drayton Windows Limited.

A template of the window openings was created in our factory to facilitate the off-site manufacture of the units. This promoted improved quality with a defect free installation. Every 9m2 screen was produced in a controlled environment and sent to the site complete, quality checked and ready to install.

The time taken for each screen to be hung with pre-positioned brackets was 30 minutes, considerably reducing the time on site.

The screens were installed using a power winch attached to a running rail on top of the 8th floor.

Each screen was attached to a bespoke lifting beam and winched in to place between the scaffolding and the existing façade. The new screens were installed in front of the existing windows. This allowed the building to remain watertight during the installation as the existing windows were removed after the new frames were installed.