Major refurbishment of the Westgate Hall in Canterbury
A major refurbishment of The Westgate Hall in Canterbury, Kent is underway. Originally built in circa 1913, the hall is now undergoing a complete transformation to become the ‘Westgate Community Hall’. Under the Architectural guidance of Paul Mallion (Conker Conservation) and Tim Ellis Conservation Architect, with main contractor B W May, the project is due for completion Autumn 2014.
The roof over the hall spans 15 x 30m with simple steel trusses and steel purlins, supporting diagonal timber boards and 1960’s vintage asbestos slates. To thermally and acoustically upgrade the roof, the covering was stripped back to expose the timber boarding, new steel purlins were installed above the boarding supported on steel connectors to the trusses. These support a new run of Steico I Joists (SJ 60x200 approximately 9m long) forming the new rafters across each side of the roof. The ridge detail comprised of plywood gusset plates glued and screwed to both the web and flange material of both of the incoming joists, creating a strong connection detail.
Adrian Judd of Steico UK Ltd commented “I joists are well known for their use in floor applications, but due to their high strength to weight ratio, also lend themselves extremely well for roof applications. The joists can span further than traditional timber and can be supplied in lengths of up to 13m, often at spacings of 600mm. Joist depths from 160 -500mm create a void for super insulation to be installed. Lighter than solid timber and easy to handle, make ‘I’ joist the ideal partner for roofing contracts.
Paul Mallion, Director of Conker Conservation Ltd commented “We were looking for a means of raising the roof to accommodate 300mm of insulation; support a new slate roof and the new ventilation cowls; whilst permitting the use of an uninterrupted airtight layer below the insulation. Working with engineers BSF Consulting we developed a relatively lightweight solution that allowed the existing roof trusses and boarding to be retained. The Steico joists, supplied by Travis Perkins, were long enough to span the ridge to eaves in one section, and light enough to avoid the
need for cranage.”