Bob Marshman Building featured in The Fifth Estate

The Construction Training Centre’s Bob Marshman Building has been featured in The Fifth Estate in an exciting long-form feature written by our very own Dominika Richards.

Brisbane’s Bob Marshman Building is Australia’s first certified Passivhaus Plus training facility – here’s how they did it

The Bob Marshman Building, completed in July 2024, is Australia’s first certified Passivhaus Plus training facility, which is no doubt why it was featured at the Australian Passivhaus Association’s THRIVE conference this year.

This is innovative due to the building’s subtropical context, where Passivhaus certification is not as commonly applied in cooler, less humid climates.

The Passivhaus certification requires an extremely airtight building envelope with significant amounts of thermal insulation, thermally broken windows and a sophisticated heat recovery ventilation system, which reduces the cooling energy required. The building design incorporates the five elements of Passivhaus, including the thermally broken windows, an adequate ventilation strategy, and achieves air tightness, eliminates thermal bridges and has appropriate thermal insulation. Additionally, subtropical design principles such as orientation, rainwater collection and passive design strategies were key to the project’s design from the early concept stages.

Brisbane’s Construction Training Centre (CTC) approached Deicke Richards to deliver a new training facility on the campus’s visually prominent yet underutilised vacant site.

The CTC established strong sustainability ambitions for the project to be built as a living laboratory and a pathfinder exemplar demonstrating how high performing, carbon neutral buildings constructed with traditional building materials could become the new norm within the construction industry. An early cost analysis was undertaken between a traditional construction approach and the Passivhaus pathway, determining long-term energy cost savings when proceeding with Passivhaus. Apart from the ambitious sustainability targets and the need for future flexibility between training spaces and offices, the brief for the training facility was quite open.

The architectural response explored emergent passive thermal design principles, sustainability, and the impacts of these on construction education pathways. The building consists of a simple cruciform floor plan which provides good permeability, light filled corridors and helps flexibility for different breakups of tenants. At the heart of the plan is a kitchen and outdoor recreation space with views towards the creek.

Due to its integration of Passivhaus in a subtropical climate, there were many challenges faced by the design team, including the detailing of the continuous airtight barrier to achieve the building’s airtightness at 0.6 @ 50 Pascal air changes an hour that must be met under the certification.

The membrane had to be detailed on the outside to reduce condensation due to the humid climate. Consideration was given to how each building material interfaced with the membrane, including a thermal break between external and internal slabs, using only screws for the CFC rainscreen battens, and ensuring that the brick ties were thermally broken and did not punctuate the membrane. Other issues included how the airtight barrier would continue around the building eaves, which are a design element critical to shading in subtropical climates.

To minimise the chance of leaks by wrapping the membrane around the eaves, this was resolved through detailing the roof to create a flat surface for the airtight barrier, and a secondary framing system to ensure the membrane could wrap down the external wall. The building was designed to have a timber stud frame and roof structure due to being more sustainable, as well as to minimise thermal bridging. To resolve the complex detailing challenges, the client CTC, architect Deicke Richards, the project manager John Gaskin, the environmental consultant Ecolateral, the contractor Hutchinson Builders, fire engineer Walkerbai, and the engineering services consultants BEC Engineering worked together collaboratively to resolve these complex issues applying the shared enthusiasm to deliver a pioneering learning environment within the Queensland context.

The building’s learning environments offer superior indoor air quality through the sophisticated heat recovery ventilation (HRV) system, supplying a continual intake of fresh air. This results in very low CO2 levels within the building. The humidity and high occupancy rates within the training rooms were addressed through the implementation of dehumidifiers. Additionally, low VOC and low formaldehyde products were used throughout to accommodate the toxin free requirement, and indoor air quality is continually monitored through air quality monitors throughout the building. The HRV, coupled with airtightness and double insulation, promotes a high degree of thermal comfort in the learning environment. The double insulation also provides benefits in the form of the building being very quiet. The external noise from the adjacent road is minimised, and the background noise is eliminated. The training facility also feels very calming and has positive effects on students experiencing stress and anxiety during examination periods.

There were several sustainable design selections implemented in the project, that contribute to lowering its overall carbon footprint, maintenance and deconstruction and add another learning layer to the Living Laboratory concept. These include the emphasis placed on Australian made, locally manufactured, robust, and easy to maintain materials with lower embodied carbon. Circularity was stressed with cradle-to-cradle focused selections with high recycled content and opportunities for end-of-lifecycle reuse and recycle. Some examples of the rigorous material selection process included bricks with recycled content from Cross River Rail sites made in Brisbane, SEQ grown and locally processed hoop pine for plywood joinery, kitchen benchtop made by Five Mile Radius from concrete and aggregate salvaged from construction sites, eco plasterboard and Australian made recyclable carpet tiles with recycled fishing nets content and post-consumer PET recycled pinboards.

Low toxicity of building products was critical in the selection process and included consideration of VOCs in paints, sealants, adhesives and formaldehyde content in cabinetry and plywood joinery. All appliances were specified in early documentation stages and input into the passive house planning package to ensure that the energy consumption did not affect the Passivhaus operation. All fixtures and fittings were selected to be hard wearing, low maintenance and, water and energy saving where applicable.

Other passive design strategies included solar panels, EV chargers and rainwater systems for use in the amenities. The building is effectively airtight at 0.6 air changes an hour at 50 pascals of pressure and eliminates thermal bridges to ensure energy conservation. The total carbon footprint of the project was 141,810 kilograms of CO2, and the construction part of the building reached net zero in October 2024 (about 3 months after completion) through on-site renewables. The building is a demonstrated exemplar of how buildings can be adjusted to climate change.

A life cycle analysis undertaken by WSP found a 24 per cent reduction in carbon emissions compared to a traditional building approach. To further support CTC’s vision for the building as a living laboratory, the building itself acts as an educator and trainer through QR codes placed around the building that describe the various environmental and Passivhaus elements to its occupants.

The project’s sustainability targets and certifications did not impact on time or money, finishing on time and under budget. This is replicable, especially as it offers a solution to passive heating and cooling where a hot and humid climate is a challenge. The success of the project is due to the whole consultant team as well as the sustainability ambitious client whose drive to build better and mantra of “inform, challenge and excite” was the driving force behind the project. The training centre is highly energy efficient, quiet, climatically controlled and boasting superior air quality. It is proof that Passivhaus certified learning environments in subtropical climates are not only a possible but also highly desirable, value adding propositions.