It’s just a few years since New Zealand’s first 10 Homestar rated house was completed in Christchurch. Ockham Residential has just matched this best practice rating for its recently opened Daisy apartment building in Auckland’s Mt Eden.
Initially appraised with a 9 Homestar rating, the highest assessment given to an apartment block at that time, the final rating achieved by this ground breaking project was actually 10 – thanks to some inventive and gutsy design elements, the latest green technologies and the inclusion of Firth’s EcoLabel certified concrete – EnviroBlend®.
Ockham has been responsible for several other high-quality developments around Auckland including the Hypatia apartments in Khyber Pass, which were given a 6 Homestar rating and completed in 2016. The company says it tries to make its buildings as energy efficient and sustainable as possible. But the Ockham team has taken things to the next level with Daisy. Its members talk proudly about New Zealand’s greenest apartment building, and sustainable, low energy urban living.
“We experimented a lot on Daisy,” says Martin King, Registered Architect for Ockham Residential. “We have included dedicated scooter/bike parking, heat recovery, hot water systems, solar power, rainwater harvesting and construction methods such as Speedfloor, insitu concrete walls and Firth’s EnviroBlend®.”
One pretty radical design feature is that the building, a mere 3km from Auckland’s CBD, doesn’t include parking spaces. Instead there are 40 spaces for bikes, 15 for scooters and two CityHop shared cars are available for residents use.
A factor critical in helping the Ockham team achieve its unprecedented 10 Homestar rating was the use of EnviroBlend® from Firth. “We have used Firth for our concrete and concrete products supply before but we were directed to their EnviroBlend® concrete by Matt Wilson of Ecolnsite, our external Homestar consultant,” explains Martin. “Firth’s EnviroBlend® concrete, which includes a 15 percent cement replacement of fly ash, provided four points toward the materials credit, which is a significant amount. Seventy three percent of the building’s concrete is Firth EnviroBlend®.”
“Concrete has many advantages, including good acoustics, strength and longevity which all align with Ockham’s desire to produce a legacy of housing infrastructure that will endure for generations,” says Matt Wilson from EcoInsite. “A criticism of concrete is the energy involved in the material’s manufacture. Using the Firth EnviroBlend® concrete with Golden Bay cement and flyash substitution significantly reduced the carbon intensity of the structure and this was recognised with very valuable concrete points in the Homestar materials credit.”
“Firth was very accommodating and brought a lot to the table when it came to achieving our Homestar goal,” adds Martin. “There was a huge learning curve on all aspects of the project but we believe the result has been worth it.”
Green technologies
Daisy is packed with systems that support sustainability and energy efficiency. The apartments include a clever heat-recovery ventilation system that exchanges cold air for warm, and a solar farm on the roof that drives pumps to heat the building’s hot water. Argon-filled double-glazing, high levels of insulation, appliances with high-energy saving ratings and low-energy LED light fittings will all help make Daisy a great place to live and a building that does its bit for the environment.
Firth EnviroBlend®
“Our Hamer Street branch in Auckland city was approved with the EcoLabel for our EnviroBlend® mix after we satisfied a variety of environmental criteria,” explains James Willoughby, Environmental Manager for Firth. Stipulations require that:
- Cement must meet requirements of EC-42-10 for Portland Cement (Golden Bay Cement)
- Aggregate must be from an approved supplier (Winstone Aggregates)
- An annual report is supplied detailing recycled products used, the percentage included, their source and the results of chemical testing
- Hazardous substances are excluded
- Policies and procedures are provided for water management
- The pH of discharged water is in the acceptable range of 6-9
- Cement silos include fabric filters, overfill sensors and that cement is transferred pneumatically
- Discharges to air are below the required amount
- Dust is managed effectively
- Truck washing practices are met
“All these factors were considered before an EcoLabel was issued to our EnviroBlend® product,” says James.
About Homestar
- Homestar was developed from successful international rating tools and adapted for New Zealand’s specific conditions. It can be used on any residential building, from stand-alone homes to multi-unit dwellings.
- Homestar is a comprehensive, independent national rating tool that measures the health, warmth and efficiency of New Zealand houses. A home is rated on a scale from 6 to 10.
- A 6 Homestar rating or higher provides assurance that a house will be warmer, drier, healthier and cost less to run than a typical new house built to the building code. A 10 Homestar rating means you’ve built a world leading house!
Project summary:
Customer: Ockham Residential
Architect: Martin King, Ockham Residential
Homestar Consultant: Matt Wilson, Ecoinsite
Construction Contractor: Ockham Construction Limited
Location: Akepiro Street, Mt Eden (Auckland)
Product: Firth EcoLabel Certified concrete– EnviroBlend®
