Vancouver's mostly lame-duck council has approved a fairly monumental change in zoning just over a month before the next election.

As part of the "Making Room" program, duplexes have been legalized in virtually all of the city's single-family neighbourhoods.

This mass rezoning of 52 percent of Vancouver's land mass is likely the last major move by the Vision Vancouver–controlled civic government.

Four of Vision's five councillors and Vision mayor Gregor Robertson are not seeking reelection.

“The decision by council to make it legal to build duplexes in single family neighbourhoods across Vancouver is one more step we’re taking to boost the right supply of housing for people who live and work in Vancouver,” Robertson said in a news release from the mayor's office. “This is not a silver bullet for Vancouver’s housing challenges, but we have to deal with the fact that more than half of the city’s land base is zoned exclusively for single family homes—homes that are out of reach for the overwhelming majority of residents."

This enables four units on each property because the two units in the duplex can each have a secondary suite.

There's previously been a maximum of three dwellings, including a laneway house.

"Over the past two years of consultation for the new Housing Vancouver strategy, we heard loud and clear that Vancouverites want more housing options in single family neighbourhoods," the mayor declared. "Allowing duplexes, which are already permitted in neighbourhoods like Kitsilano, Strathcona, and Grandview-Woodland, is a modest but important change to provide more housing options.”

It opens the way for more residents in neighbourhoods such as Dunbar, Kerrisdale, and West Point Grey, according to the news release.

No increases in height or floor-space ratio have been allowed as part of the changes.