Crone’s refurbishment of 20 Martin Place, Sydney has outstripped its sustainability expectations and achieved a Green Star As Built rating of 6 Stars.

Delivered by construction company Built, the $110 million project intended to achieve a 5 Star Office As Built v3 rating but instead targeted and achieved 6 Stars at no extra cost to its client, Pembroke Real Estate.

The achievement came courtesy of two additional Green Star points and 10 innovation points that the project team quickly identified for implementation without increased capital cost to the client.

The result is World Leadership status as a green building for the project, with a total point score of 77 points awarded by the GBCA during the Round 1 submission – a rare occurrence.

WHERE THE POINTS CAME FROM (courtesy of Built)


Of the 10 innovation points, eight came from Innovation Challenges offered by Green Star. This including using 64 per cent zero VOC paints, contractor sustainability education and materials life cycle assessment.

Built used an EN15978 compliant Life Cycle Assessment which concluded that retaining the 22-storey structural steel frame within the building would save 1,291 tonnes CO2e, while replacing 30 per cent of cement with fly ash would save 2,809 tonnes.

To put these figures in context, the building is projected to emit 107,000 tonnes of CO2e emissions in operational energy use over the building’s expected 60-year life. So initiatives that improved operational energy savings provided a key avenue for carbon abatement in the Life Cycle Assessment.

20 Martin Place is also one of Sydney’s first commercial office buildings to be delivered with LED light fittings installed to all office floors. This has resulted in an average lighting power density of 1.34W/100 lux, or an 11 per cent improvement on the most stringent Green Star benchmark.

In addition, the building features a 100% outside air system served via chilled beams at perimeter and VAV in its centre zone. 1.9L/min ultra-low flow basin taps throughout and 106-bike spaces with 13 low flow 6L/min showers help save water. Ultrasonic sensors in all fire stairs improve safety for all tenants and 95% of the waste generated in demolition and construction was diverted from landfill.



The 20 Martin Place project involved the complete reconstruction of the out-dated, 20-storey, 1970s office building, transforming it into a signature building in the heart of Sydney’s CBD. The building’s design strives to deliver optimum flexibility and cutting-edge, sustainable performance, including:

  • A new high-performance glass façade with VLT of 49%, SHGC of 0.27 and U-values of 3.1 and 3.3 on main facades
  • Side core design for more efficient and flexible floor plates
  • Interconnectivity between floors 
  • New building systems, technology and services 
  • New end-of-trip facilities.
  • Maximum daylight penetration. 

 The new A-Grade commercial office and retail space targets a minimum 5 Star NABERS energy rating and achieved a 5 Star Green Star Office Design v3 rating as well as a 6 Star Green Star Office As Built v3 rating.

Tenant comfort is further optimised by enhanced ventilation and air quality as well as maximised natural lighting and views.