Offices of the Environment Agency, Bodmin
Form Design Group
A timber-framestructure with louvre screen and rooflights
The building is a single-storey timber-frame structure; a series of 250 x 325mm green oak columns and 350 x 350mm Douglas fir beams which span 5.5m and run below the central rooflight. The beams are half-lappedto the tops of the columns and pinned with stainless steel threaded rods in epoxy-filled holes.
A central rooflight runs from north-west to south-west in a double pitch of patent glazing supported between treated timber mullions. Each side rests on an upstand kerb of laminated Douglas fir secured with coach screws to a steel angle. A fabricated Douglas fir ridge member is dressed with lead.
The roof is covered with an Erisco-Bauder Eco-roof, an 'extensive' type comprising a top layer of vegetation growing on an expanded shale substrate. The roof is a complete system - insulation, vapour barrier, waterproofing and plant-growing medium - which is laid on the roof deck. Rainwater drains off the rooflights on to a gravel margin and waters the rooftop vegetation.
The south-west facade is made up of a treated timber sub-frame inset with fixed and opening double-glazed windows. The oak-faced spandrel panels below are 'breathing' walls with Masonite sheathing filled with Warmcell recycled insulation. At the eaves runs a sunscreen, doubling as a planting frame. It is formed of tapered 219 x 72mm joists bolted to each side of the Douglas fir joists and projects beyond the facade to a delicate edge, capped with an apron of terne-coated stainless steel. Pairs of sequoia louvres are set between the joists. The sunscreen is supported by green oak columns fixed at their bases to rhs stub columns.