The building consists of 2 primary volumes arranged in a T shape. The stage is located in the taller of the two volumes, with a footprint of approximately 7.5 x 15m, it is about 9.5m at its highest point. This height is required to house the fly system of stage rigging for lighting and sets to be lifted up and down during performances. The shallow 5 degree gradient of the stage roof is supported by 3 glulam beams. These beams span about 7.5m from the back wall of the stage to the lintel that forms the proscenium arch at the front of the stage. The glulam beams are notched into CLT wall panels, one is located along the ridge and the other 2 pick up the mid-span of the roof panels.
The Auditorium is housed in the second volume that sits perpendicular to the stage and is centred on the same central gridline as the stage. In the long section the roof steps down over the Auditorium as does the ground, making room for the front 4 rows of raked seating. The ridge of the roof follows the same line as the Stage. This time the glulam beams are spanning the same direction as the gradient of the roof and so these beams are cut in the factory to form the gradient for the roof panels.
A third, single storey, flat roofed volume wraps around the auditorium’s north and west elevations housing the main entrance lobby at the front and the side entrance to the auditorium. The fourth and final element of the building is the glulam portico structure at the front of the building which connects to a sheltered walkway along the west elevation of the theatre. This playful piece of structure is taller than the building, it is made of pressure treated pine glulam and is fully exposed to the elements. The portico structure echoes the diagonal lines of the red wood fibre cement cladding panels. It is a sculptural element creating a dramatic threshold to the new theatre.
Together with the use of sustainable materials, low operational carbon was fundamental to the overall design philosophy. The use of high levels of insulation together with passive heating and cooling measures allowed for the removal of mechanical or active H-VAC or cooling systems. Around the building, strategically placed vents, specially designed in areas for acoustic performance, allow natural temperature control and air change, while not detracting from the acoustic qualities of the theatre space.
Timber was central to the ambition of building a low energy structure and allowed the team to offset 100 tonnes of CO2 through the sequestration of carbon within the 143m3 CLT and Glulam structures. When we consider the As-built BRUKL total carbon emissions for the building at 41.8 kgCO2 / m2 / annum, we find that the timber has offset over 5 years of operational carbon.
Client: Horris Hill Prep School
Architects: Jonathan Tuckey Design
Timber Engineers and Specialist Installers: Eurban
Engineers: Webb Yates
Main Contractors: Vale Southern Construction
Suppliers (CLT): Stora Enso
Suppliers (External Portico): Piveteau Bois