PROCTOR AIR, the roofing membrane for the future developed by A. Proctor Group, is being installed as part of the renovation of Manchester Town Hall.
Once construction work is completed on the historic building, which is almost 150 years old, it will benefit from Proctor Air’s combination of vapour permeability and air permeability.
At roof level, the restoration efforts include dismantling and rebuilding 30 of the 34 chimneys and replacing 140,000 roof slates.
Removing the roof finish has afforded the opportunity to install a new pitched roof underlay. The project architects specified Proctor Air, with Mac Roofing & Contracting Ltd carrying out installation.
As an historic building, the Manchester Town Hall roof features many intricate details. The complexity of the roof forms, combined with the age and heritage value of the building fabric, means that opportunities to provide modern roof ventilation are limited.
A key advantage of Proctor Air, as an airpermeable low-resistance (APLR) membrane, is that it removes the need for separate roof ventilation. In fact, it provides a more uniform flow of air in the roof space than normal vents, ensuring there are no ‘dead zones’ where the complexity of the roof form could otherwise have restricted air movement. Air permeability performance is important, but must work alongside good vapour permeability performance. With an Sd value of 0.015 m and a vapour resistance of 0.075 MNs/g, Proctor Air is one of the highest performing vapour permeable membranes on the market.
BBA-certified, it simplifies pitched roof constructions, being both air-permeable and vapour-permeable.
