Entrant:
Sheppard & Rout Architects & Arthouse Architects
Category:
8. Sustainable development award
Photographed by:
Virginia Woolf
Overview
Waimea College
The development of 15 new teaching spaces at Waimea College led to early discussions with the Ministry of Education from the design team requesting the opportunity to explore a mass timber option.
Two high level options were presented. The first had structural steel framing, light weight steel purlins and a suspended concrete floor. The second was a timber alternative incorporating LVL beams, Glulam beams and short return LVL shear walls spaced at 7-meter centres, along with Potius prefabricated mid-floor and roof cassettes spanning between the portals to form the superstrucutre. Both options had a high-level cost estimate check, which also included efficiencies in programme and constructability. Based on the costing exercise, the timber option moved forward.
This project is a step-change for the Ministry. Our understanding is that this is the first time a mass timber solution to this extent has been utilised for a public sector college in New Zealand. The design team has been working closely with the Ministry to further develop the system and a further refinement is currently under construction at another school in the same region.
Incorporating flexibility within / between learning spaces is a key driver for educational projects, alongside affordability, robustness and weathertightness. The large 8.5m open span off the end of the shear walls provides uninterrupted space that can be adjusted if the needs of the school change during the lifetime of the building.
Waimea R block superstructure is estimated to have 36% less gross embodied carbon when compared to a conventional reference building. The timber superstructure also sequesters an estimated 117 Tonnes CO2. With the estimated total carbon sequestered of building being approximately 140 tonnes.
The timber main structural framing comprises 7% (37 t CO2e) of the gross embodied carbon compared to reference case which has steel as the main structural framing material comprising 25% (151 t CO2e) of the gross embodied carbon.
Timber sizes were carefully considered to reduce waste from billets, eg the mid floor and roof beams where designed to be 700mm and 500mm respectively so they could be formed out of a standard 1200mm billet. Bolted connections were designed to allow for simple dismantling of the building at its end of life.
The decision to expose as much timber as possible was made to allow the building to be used as a teaching tool, including exposing the LVL bracing component of the shear walls in classrooms. Where the timber is structure exposed it provides a natural warmth, and creates a visually appealing and inviting environment in educational buildings, aligning with an intention to create more biophilic focused learning spaces.
Transportation wise, the LVL by Nelson Pine and Potius Cassettes are both locally sourced and manufactured in the region, reducing the environmental impact of delivery.