While working on the German International School Sydney (GISS) Masterplan, the client required an interim solution involving portable classrooms. The challenge was to rethink the very established Australian ‘demountable’ which features throughout most schools in Australia, and achieve a modern solution aligned to our strong advocacy for sustainability.

The goal was to build sustainable portable classrooms at a cost and time frame equivalent to traditional portable classrooms and attain the International Passivehouse Standard using timber as the primary construction material.

The result is s.e.e.d.; a prototype for a new s-ustainable e-nvironmental ed-ucation space and the antidote to traditional demountables.

Each mass timber classroom was preassembled off site, craned into place in five modules and installed in less than 90 minutes per building. Designed and constructed to the International Passivehouse Standard, the classrooms allow for filtered, clean air and thermal comfort year-round, while reducing heating and cooling demands by 90 percent.

The use of timber counteracts humidity levels to reabsorb humidity during wet weather and release in dry weather, naturally helping to create a balanced indoor comfort. It also connects the buildings to the surrounding bushland setting.

Clean and fresh filtered air is supplied within the Passivehouse envelope through Heat Recovery Ventilation units which maintain a constantly comfortable room temperature. Not only beneficial in hot and cold months or to students with asthma and allergies, HRV units are valuable additions throughout the bushfire season and help keep CO2 levels below a critical 800 ppm in all classrooms.

Considering the continued demand for portable classrooms across Australia in the foreseeable future, we hope to see these s.e.e.d.’s become an integral part of a sustainable growth strategy within the education sector.

The initial brief incorporated a 10-year masterplan for the entire school campus including new admin spaces, a ‘state of the art’ science centre exhibiting a strong focus on sustainability, preschool and after school care facilities, etc. However, there was an immediate requirement for three classrooms to be installed within a short timeframe to accommodate an influx in student numbers and ease pressure on existing (small) classrooms. Initially these portable flexible learning spaces were to be purchased or rented.

Considering the cost, timeframe, and quality of the standard, readily available demountable that the Australian market has to offer, it was obvious these would not align to the school’s or the architect’s general ethics of planning and building.

With no sustainable options on the market, the school and Architects decided to take on the challenge to design and build these demountables within the required parameters:

• As energy efficient as possible

• Cost efficient building equal to a standard demountable

• Timeframe of delivery and installation, to be equal to a standard demountable

• Create a healthy learning environment

• Educate and provide students the space to learn in a positive, calm, and natural environment

• Integrate biophilic design principles Primarily, the modular learning space design directly responds to the goals set out by the school and wider community as above.

The design also caters to a wide age range of student due to differentiations in ceiling heights between the main space and the window nooks. The deliberate limited use of colour and prevalence of natural and sustainable materials (timber) forms the calm backdrop for learning.

The project has been designed to achieve the stringent ‘International Passivehouse Standard’. This certification process, together with the blower door test are currently being prepared. The learning spaces were part of the recent International Passive House open day and once certified, s.e.e.d. will be Australia’s first Passivehouse certified portable classroom.

Using the Passivehouse standard ensures the building only consumes minimal energy for heating and cooling (less than 15kwh/m2/year). This is achieved using solid CLT walls in combination with high insulation values and the heat recovery ventilation, which supplies constant fresh and filtered air to the building.

All the windows are tilt-and-turn, which enables night purging to cool down the space throughout the summer and during night. Both measures ensure that all year round the building will maintain a temperature range for thermal comfort between 20-25 degrees, which prevents mould or condensation to form.

As mentioned, the use of CLT, increased insulation and adhering to the Passivehouse standard will ensure a year-round energy use for heating and cooling of less than 15 kwh/m2/a. The untreated timber cladding ensures minimal maintenance over the years, with no resealing or painting required.

The solar PV system provides the classrooms with more energy than required, therefore surplus is distributed to remaining campus. Where other building materials such as steel or concrete emit carbon in their production process, timber stores the carbon.

The difference between a traditional steel demountable and the installed prefabricated mass timber structure is equivalent to 63 t stored CO2 and 22 t avoided CO2 emissions (including overseas shipping).

The entire timber used in this project is regrown in the originating forests within 17 seconds, and as such is a truly ‘renewable’ building.

Sponsored by NextLink by Timberlink