The director of the Art Gallery of Greater Victoria (AGGV), in British Columbia, Canada, has defended the CA$22m (US$17.3m, €15.6m, £11.2m) expansion and renovation of the gallery after the city’s mayor called the plans “startling.”

“It’s more astonishing than startling,” said Jon Tupper, following comments from Victoria mayor Lisa Helps. “It’s going to be like an art cloud. That’s what we’ve been calling it.

“The city needs a gem of a building – something we can bring our visitors to or our families when they come to town, that we can be proud of.”

Speaking at a recent public meeting, mayor Helps called the proposal “startling” and “very bold”, with a city report also raising concern that the new building form and massing would “obscure the current visibility of the historic Spencer Mansion, where the character-defining elements are located, from vantage points along Moss Street.” With the proposal, Spencer Mansion is visible from inside the new addition.

The design, by Lang Wilson Practice in Architecture Culture (LWPAC) and Moore Architecture, was selected following an international design contest, with the winner chosen from three shortlisted firms. The modern three-storey glass and concrete building will be linked to Spencer Mansion, which currently houses AGGV, by a ground floor glass atrium. The extension’s second floor will be wrapped in an aluminum skin mesh that will reflect both the sky and the canopy of trees around the gallery. The expanded art gallery would include exhibition galleries, classrooms, gathering spaces, gift shop, storage and offices, a theatre and a café.

AGGV is home to the largest collection of art in western Canada, with 18,000 pieces including contemporary, Asian, new media and native art collections among its range. In its current home, only 5 per cent of its CA$203m (US$160m, €144m, £104m) collection, is on display at any one time.

Slated for completion in Q3 2017, LWPAC are operating as lead design architects for the project, while Moore are contributing their local experience based on major projects in Victoria and their understanding of approval processes, heritage alterations and construction procurement.