Developers offered a sneak peek of proposed plans for the former Canada Post office in downtown Vancouver on Wednesday night.

It's been three years since Canada Post vacated its former office on West Georgia Street. Developers Bentall Kennedy hope to turn the property into a mixed-use tower with residential units and retail space.

The former Canada Post headquarters was built in 1958 and takes up an entire city block. Mail was once transported through tunnels from the building to the Waterfront train station.

Bentall Kennedy has unveiled plans to transform the structure into a 19-storey office tower with 850 rental and condo units.

"Vancouver really needs more affordable housing, more rental housing. So we want to try and support that initiative," said Bentall Kennedy executive Tony Astles.

An artist rendering of the mixed-use development proposed for the Canada Post office in downtown Vancouver. (Bentall Kennedy)

The proposed plans also have plenty of retail space for shoppers. Astles says the company has been working with city staff to meet the needs of the downtown core.

"Given the large site, we need to break up the mixes and the uses there," he said.

Heritage preservation challenges

The redevelopment has its challenges. The former Canada Post office has been called a fortress, with plenty of heritage value. Astles says the Bentall Kennedy redevelopment will try and preserve that.

"It will be the largest heritage revitalization in the city's history if it goes ahead," said heritage consultant Donald Luxton. "The scale of the building is amazing — it's massive."

Many of the attendees at the open house on Wednesday seemed on board with the plans, although some said they were hoping for more of an infusion of arts and culture into the space, and services that appeal to a broader community.

Developers plan on submitting a rezoning application to the city in about two months.

If the city approves the proposal, the project could be complete by 2021.