The city is taking an unprecedented step to give more than 250 midtown Toronto properties heritage status in one fell swoop, a move that's taking some owners by surprise.

The Toronto Preservation Board voted unanimously to approve the first phase of its "Midtown in Focus" plan, which adds 258 properties on Yonge Street, Eglinton and Bayview Avenues and Mount Pleasant Road to its heritage register.

The plan still has to be approved by city council, but Coun. Josh Matlow says he's confident it will pass, something that could maintain many of the low-slung brick buildings that line those streets. The full list of buildings can be found here.

"The majority of councillors recognize that Toronto has a shameful legacy when it comes to heritage preservation," Matlow told CBC Toronto.

"Far too many architecturally or culturally important properties have been lost to the wrecking ball."

This is going to change things dramatically. - Coun. Kristyn Wong-Tam

The city has been stung by the loss of at least two century-old buildings — including an old Bank of Montreal branch and the former Stollerys building — in recent years. Without heritage protection, developers could easily get a demolition permit from the city.

If the buildings are added to the heritage register, the city would get at least 60 days to potentially block future demolitions.

Matlow said the city is moving quickly and, until now, quietly to protect the buildings so property owners don't try to get rid of them before the new rules take effect.

Workers demolish the facade of the Stollerys building at Yonge and Bloor. (CBC)

Owners, developers flag concerns

While several neighbourhood groups are applauding the move, others are voicing concern.

BILD, the home builders' association with some 1,450 member companies, said in a letter to the preservation board that it was surprised by the city's approach, especially given the limited information it received about the change.

"The city's own report acknowledges that this large number of properties being added to the heritage register at one time is unprecedented," BILD's senior manager of policy and government relations, Danielle Chin, wrote to the board.

"Change of this magnitude should always trigger an industry consultation meeting."

Jack Winberg, the president and CEO of developer Rockport, which controls four properties on the list, expressed similar shock in his letter to the board.

"We did not receive any notice of this report or the intent to list our building as having heritage, contextual or cultural value; we are not of the view that it has any," he wrote.

City council gets final say

At Thursday's meeting, architect Michael McClelland said while he supports a city-wide survey of heritage properties, he's alarmed by the city's aggressive stance, suggesting it should find a way to do more consultation with owners.

McClelland also questioned whether or not many of the buildings would qualify for full heritage protection, suggesting while they're "good, stable" structures, they may not meet the full criteria.

Coun. Kristyn Wong-Tam, who sits on the board, asked the same question to staff, and was told in response it would definitely allow city staff to move faster to block demolitions.

Wong-Tam says she believes the city will need to do some work to educate the public about its new approach to protecting batches of buildings at a time.

"This is going to change things dramatically," she said.

City council will vote on the matter at an upcoming meeting.