HAPPY workers are productive workers. A building must suit its local environment. Deceptively simple concepts that just may prove key to determining who will win the Australian Institute of Architects' 2009 national commercial architecture award tomorrow.

Both concepts are embodied in two very different Victorian office buildings: the headquarters of Sussan in Cremorne (pictured) and the Bendigo Bank in Bendigo. A win for either will cement the growing influence these concepts are exerting over the commercial property industry.

"There's no doubt they are both showing the way for office accommodation in Australia," Howard Tanner, chairman of the national awards jury, told businessday.

The Sussan/Sportsgirl headquarters, designed by Sydney-based Durbach Block, transformed - rather than destroyed - three old warehouses on the former Rosella factory site into a single structure under a contemporary unifying facade.

"You're reinventing the life of that building rather than just tearing it down, throwing all the stuff in landfill and starting from scratch," said Durbach Block principal David Jaggers.

In Bendigo, BVN Architecture and Gray Puksand faced a very different challenge in making a new state-of-the-art office blend into the arguably most intact and grand Victorian-era city in the country.

"Bendigo Bank made a clear decision to maintain their headquarters [there] to help rejuvenate that part of the city," said BVN principal Bill Dowzer. "The design process very much involved partnering with the community."

That meant designing a structure that matched the scale of the local buildings and creating accessible laneways for retail, a landscaped board walk and a new public square.

Yurie Tyblewych, director of planning and urban development for multinational services firm AECOM, said this approach would prove essential to reconciling practical building needs with community expectations as cities became denser.

But while the Sussan and Bendigo Bank buildings may be radically different in appearance, both are organised around the central principle that an office must be a comfortable, even enticing, work environment.

They are competing for the national commercial architecture award against 12 other contenders from around Victoria and Australia.