Sustainability was identified as the key objective during the construction of student residences at the Inveresk campus of the University of Tasmania.

The University’s National Rental Affordability Scheme apartment project at Inveresk is Tasmania’s first ever multi-storey mass timber residential development. Located on the banks of the North Esk River beside the University’s Inveresk campus, the development comprises of 120 apartments across two three-storey buildings, connected by common social spaces, external landings, and stairs.

The development was designed by a consortium led by Morrison and Breytenbach Architects. Prioritising sustainability in the project, the University’s Centre for Sustainable Architecture with Wood (CSAW) selected timber for its low carbon footprint, lightweight structure, which reduced the foundation system, and renewable properties.

Faced with a strict deadline and difficult site conditions, XLAM worked with project stakeholders to provide a lightweight and time efficient solution using cross laminated timber (CLT). This decision allowed the construction to continue unhindered and to schedule despite the challenging 18-metre-deep silt riverbank site conditions.

Through the extensive use of timber, which replaced less environment-friendly materials such as concrete and steel with XLam CLT and Laminated Veneer Lumber (LVL) support structures, the University was able to achieve the sustainability goals set for the building. The relatively lightweight nature of timber also made it the most suitable material to combat the challenging site conditions of the prevailing 18-metre-deep silt riverbank.

This resourceful approach to sustainable prefabricated student apartments received considerable recognition and went on to win the 2016 ATDA Engineered Timber Products Award for an innovative system of sustainable design.

Structural Design

With speed of construction being paramount to meeting the project’s deadline, the XLam design team in conjunction with Hutchinson Builders developed a prefabrication enterprise close to the construction site. Here, the modular CLT apartments were fully framed, clad, and fitted out in an assembly line process, then delivered to site, stacked, and connected. This simultaneous production of multiple components of the building greatly reduced construction times and removed the need for scaffolding.

CLT panels were used for the common room floors, which in turn became the ceilings of the common rooms below, as well as for the walkways interconnecting the apartments and the XLam AirStairs. CLT was left exposed on the underside of ceilings and in the stairways and common rooms to draw the natural warmth and comfort inherently found in timber.

“Prefabricated volume modules and CLT connecting floors and walkways, working in combination were deemed to be the most suitable lightweight construction for the prevailing 18m deep silt riverbank site conditions and, in conjunction with the speed of prefabricated construction, were instrumental in making the project feasible,” said David Bylund, UTAS School Of Architecture and Design.

Due to the unique fire characteristics of CLT, it was also used as the floor material for all escape routes. The 200mm thick floor panels comprise five layers of Radiata pine lamella and are designed to accommodate substantial fire resistance, which unlike steel remains structurally stable when subjected to high temperatures.

“The XLam AirStairs took a fraction of the erection time we expect for precast concrete stairs. If I had realised how quick it would be we would have dispensed with the temporary stair. Please convey my thanks to Mike and Sam at XLam for their help and support,” said Nick Scott, Hutchinson project manager.

Weighing approximately 20% of concrete, CLT alleviated the challenge of the prevailing 18-metre-deep silt riverbank by reducing the foundation loads and distribution requirements. The flexible nature of CLT modular projects also allows for most components of the building to be dismantled. For instance, the self-contained modular apartments, modular roof, and wall screen elements can be disassembled and reused in another location.

Outcome

Through the supply of CLT for the University of Tasmania Inveresk Student Residences, XLam was able to demonstrate the efficiencies and benefits associated with large scale, mass timber projects by providing speedy, safe, and sustainable solutions.

Project Details

Project: University of Tasmania Inveresk Student Residences

Client: University of Tasmania

Architect: Consortium led by Morrison And Breytenbach Architects

Structural Engineer: Aldanmark Consulting Engineers

Head Contractor: Hutchinson Builders

Location: Invermay Road, Inveresk, Tasmania

Building Methodology: Mass Timber (CLT & LVL)