Public Trust Building

Public Trust Building


Master Builders Commercial Project Awards – Gold in Heritage and Restoration

NZIA Local Awards – Heritage Award

NZIA Local Awards – Interior Architecture Award

This landmark Lambton Quay building has been extensively seismically strengthened and refurbished inside and out to bring it into the 21st century and beyond. Careful consideration had to be given to preserving the heritage values of this building and this was particularly challenging when locating the engineering services.


  • No roof space for heat rejection plant
  • Heavyweight construction being brick, stone and concrete
  • Single-glazed openable windows
  • East and north of the building shaded by nearby buildings.
  • Limited space for plant and service risers
  • The high stud difficult to heat
  • Poor thermal envelope (in terms of insulation)
  • Draughty heritage windows
  • Previous tenants complained of being “too hot in summer and freezing in winter”.


CORA was responsible for the design of the heating, ventilation and air conditioning including the base build and and integrated tenant fit-out. Plant and risers had to fit discreetly into the building’s fabric without destroying the overall aesthetic quality.


Because the integrity of the building had to be preserved at all costs, the plant (for a custom-designed fan-coil air conditioning system) that provides fresh-air was carefully fitted in to where the old motors for the lifts had stood. All plant was integrated so that it couldn’t be visible from the street, thus maintaining the building’s beautiful exterior.

A chiller was required to cool the offices in summer and this was integrated into the building with no visual impact on the heritage façade / roof. The chiller sits in a mezzanine plant room drawing in air through the dock and discharges warmed air to the rear of the building.
Wall-mounted condensing boilers were specified that are not only highly efficient but also space efficient again ensuring that the heritage façade was not compromised.


Good levels of comfort have been achieved through close control of temperature. and high levels of fresh air being pumped into the building.