PROJECT FILES: Call us crazy, but in our design for Sydney based school Newington College’s Eungai Creek Campus on the New South Wales mid-north coast, we set ourselves a target to use no concrete, aluminium, tiles, plastic, plasterboard, paint or laminate.
These materials, although ubiquitous in our industry, are the very definition of either high-carbon, single use, wasteful or toxic. They represent a reliance on fossil carbon made abundantly manifest. They sit near the very apex of the Construction Materials Pyramid, produced by the Centre for Industrialised Architecture at the Royal Danish Academy.
Instead, we tried to build more sustainably with the lower half of the pyramid in mind. We focused on using biogenic materials like straw, timber, cork, hemp and bamboo, as well as steel which although high carbon, is lightweight, lasts a long time with no maintenance and is fully recyclable.
Why did we do this?
Now is not the time to target incremental improvements over the status quo. We have been reliably informed by the Australian Reduction Roadmap that the emissions from the construction sector must reduce by some 98 per cent in order for our industry to pull our weight in the global decarbonisation effort required. Required that is, merely to preserve earth as a liveable place and support long-term food security. We’re all aware of the disproportionate share that the construction industry has, and therefore our responsibility/opportunity to get to work on it.
What was the project brief?
The brief was to design a brand new campus for Newington College to accommodate their visionary and inspiring social service immersion program.
The site is a 200-hectare property on Dunghutti Country on the NSW Mid North Coast. Designed to host term-long camps for year 9 students, the campus supports a transformative educational experience grounded in sustainability, community service and connection to Country.
AJC was asked to design 10 new eight person student accommodation cabins, a reception/health centre and a dining hall with commercial kitchen. The total new floor area delivered was approximately 1400 square metres.
What was involved in realising the ambition on this project?
In taking upfront emissions seriously, our design process was effectively inverted. It became material-first, rather than form-first, with material selections driving the design. In fact, the first sketch for the project (before even considering a masterplan) was a loosely drawn detail for a pre-assembled Durra Panel wall panel.
All buildings were arranged from first principles according to a repetitive 1200 millimetre Durra Panel module.
There were strong synergies with real project constraints. The client’s program was tight, so the need to design and build quickly was met by repetition, simplicity, prefabrication and reduction in earthworks. All characteristics of low-carbon design principles.
The site arrangement was straightforward: the buildings were all arranged along the site contours to minimise disturbance and enable the land and water to pass beneath.
Following Dunghutti guidance, all buildings look towards Mount Yarrahapinni, the mountain to the north-east which is of Indigenous cultural significance. The dining and reception buildings flank a majestic, ancient fig. The alignment of these two buildings is cranked at the fig to create an unexpected shady courtyard which has become a place for contemplation and ceremony.
How did we go?
The design has zero ceramic tiles or laminate. The only concrete used was for accessible pathways and reclaimed precast sleepers were used for the external ramp thresholds at the cabins.
The building footings are all SureFoot steel micro-piles meaning the only architectural aluminium used was for the channels for the double-glazed Aneeta windows, set inside a hardwood frame.
Plastic, plasterboard and paint are all pesky and crept in, but in small amounts.
The project used 2500 sqm of Durra Panel compressed straw boards, which sequestered more than 60 tonnes of carbon. As well as being carbon-storing, the panels are made from 100 per cent agricultural waste.
Granulated biochar was sprinkled into the straw core during manufacturing, adding another agricultural waste stream and introducing a negative-VOC (volatile organic compounds), pollutant-trapping air filter into the very fabric of the buildings. As a result, the indoor air quality is very high.
The recycled kraft paper lining of the Durra Panel boards was sealed with a breathable natural hardwax oil by Whittle Wax.
Decking and window joinery are local and sustainably sourced hardwoods including tallowwood and blackbutt. It was beautifully made by Bakers Joinery in South Kempsey and Teal Windows in Grafton. All joinery is birch plywood. Flooring is linoleum (Marmoleum) or cork.
We didn’t get bamboo or hemp products over the line due to budget and certification challenges.
When it is time for the buildings to be removed; they can be taken down without a trace remaining on this beautiful site. The steel can be recycled, the timber reused and the straw can be mulched up to feed the worms.
The result?
As a result of the materials selected, the cabins have half the upfront carbon of standard lightweight residential constructions and one quarter the upfront carbon of a standard brick veneer slab-on-ground house, per square metre.
Each cabin has an A1-A5 upfront carbon of 20,558 kilograms of carbon which equates to approximately 260 kg a sqm, compared to the relevant base building benchmark in the Green Book (Residential Single – Light (Timber)) which is 507 kg C02e/sqm. Instead of a whole life carbon assessment or lifecycle assessment, engineers E-LAB Consulting did an upfront carbon assessment/partial LCA which focused on global warming potential for A1-A5 only.
The dining hall was excluded from the assessment; however, its construction system is the same as the cabins whilst the benchmark buildings are more carbon intensive.
What about operational carbon, water, food and waste?
The day-to-day running of all new buildings is 100 per cent electric. The dining hall roof accommodates a 65 kilowatt solar photovoltaic array (162 panels x approx. 400W/panel) which is expected to cover 80 per cent of the campus’ typical daily energy demand.
Airtightness was carefully detailed by air barrier mark-ups during the design stage. The facade is a holistic system designed to passive thermal performance and resulted in a significant improvement over the National Construction Code’s Section J requirements.
The thermal envelope when compared like-for-like with the Section J reference case results in a 49 per cent improvement in the heating (winter) scenario which is a remarkable result. Key to this achievement is RS insulation to the roof, R4 to the floor and R2 to the walls, plus an additional R0.62provided by the Durra Panel wall and ceiling lining. Glazing is all hardwood-framed DGUs CU-value 2.7, SHGC 0.71).
The site is self-sufficient for water and effluent management. Produce is grown and cooked on site by students. Composting is part of the curriculum. Surplus food is provided to community meal services.
The design directly supports the college’s educational ambition: a safe, challenging and memorable immersion experience. Architecture becomes an active participant in learning, shaping behaviour, responsibility and connection to Country. Moreover, the project was conceived to be a pioneering exemplar of holistically sustainable construction in the Australian context. The project was delivered in rapid time, to a modest budget, and with very high amenity. It has achieved its ambition, and the learnings are already informing the next tranche of low-carbon designs.
The project belongs to Dunghutti Country. We acknowledge the enduring connection of Aboriginal people to the land.
