Over the last couple of weeks Shaun and his team have been busy hand making the roof trusses for W. Smith’s. They are traditional ‘Queen post’ trusses, meaning that the rafters are supported by two upright struts (the queen posts) rather than a central support. The first completed truss was put together outside of the Joiners’ Workshop before being dismantled and used as a template for the rest. Once the right height has been reached on the brickwork of the building, the elements of the trusses will be lifted onto the scaffold by crane and fully erected on site.
The trusses of the building that we are copying, which still stands on Elvet Bridge in Durham, are just about visible in the attic. These trusses probably date to the early 1700s and are what’s called a ‘raised collar’ truss meaning that the ridge beam (or the central spine of the roof) is supported directly by the rafters with the the ‘collar’ or the tie beam connecting the two opposite rafters to provide strength. Unfortunately, while we would have loved to have recreated these trusses, our version is effectively a modern building and using collar trusses on it would not have been allowed under modern building regulations. However, when ‘translocate’ or move an old building we do have greater flexibility to work with structural engineers and building control to reused, restore or replicate ancient materials – as happened at St Helen’s Church.