Most of the feature glazing options require a redesign of the roof to accommodate them. There are two alternative roof forms which depend on the feature glazing option selected.
The first is what we call a ‘vaulted ceiling’ which employs a raised tie truss in lieu of the standard fink (W) truss. From the wall head the ceiling slopes upwards each side for a height of 1.2m to a raised flat ceiling, resulting in a ceiling line akin to half a hexagon.
The second is what we call a ‘cathedral ceiling’ which dispenses with prefabricated roof trusses and instead employs a structural ridge beam and individual rafters. The rafters run from the wall head up to the ridge beam. For wide spans it may be necessary to introduce a purlin half way up the roof slope to provide intermediate support for the rafters. The ‘cathedral ceiling’ takes the form of an inverted ‘V’ and is open right up to the ridge.