A wonderful hipped trussed rafter roof situated near the Teifi Estuary, part of the pictoresque Cardigan Bay. The roof is comprised of attic trusses, encompassing a hip roof and hip corners. The roof plane is interrupted by smaller projecting hips, providing a remarkably complex roofscape. A number of dormer windows have been incorporated into the design, allowing plenty of light into the interior and extending the usable space.
The roof is in the final stages of completion before slating and the fully breathable roofing membrane is clearly visible.
Extending Attic Space Into the Hips
The attic room space does not have to stop where the hip begins. The truss designer has available a number of options allowing the hip structure to be modified, thereby extending the ‘room-in-the-roof’. Perhaps the easiest to visualize is the ‘step-down’ attic. Each successive attic truss within the hip, steps down following the roof pitch until the hip girder brings an end to the room.
The amount of living space that can be gained from an attic hip is constrained by a number of design factors. The attic hip truss is inherently weaker but has to support the same floor load as a full truss. Depending on the truss span, his may require an increase in timber section or multi-ply trusses.
Many attic hip design issues can be mitigated at the planning stage. For example hipped roofs with larger spans can be provided with internal load bearing walls.