The mayor says allowing four-storey townhouses on some London streets is a good way to get more affordable, higher-density housing built quickly in single-family neighbourhoods, but opponents are pushing back, saying the proposal is too rushed and will change the dynamics of certain streets.

The issue will be decided on Tuesday at a city council meeting. Mayor Josh Morgan has proposed, among many other changes to The London Plan, the city's official planning document, allowing stacked townhomes of up to four storeys along streets known as "neighbourhood connectors."

Examples of such streets are: Wavell Street and Marconi Boulevard in the east, Millbank Road and Deveron Crescent in Pond Mills, Blackacres Boulevard or Ambleside Drive in the northwest and Viscount Road and Village Green Avenue in Westmount. A map that shows neighbourhood connectors can be found here.

"This was a very rushed initiative, fast-tracked without consideration and not something that we've been able to provide input on," said Laura Emily, who has lived in Old North for four years and is worried the impact of stacked townhouses in her neighbourhood, where streets such as Colborne, Waterloo and Cheapside are classified as neighbourhood connectors.

"The average height here is two storeys. Most of the lots are narrow and deep. How would it work?"

Stacked townhouses are attached dwellings but instead of a row of single-family homes, there are two units stacked on top of one another vertically. They're considered easy to build and more affordable than detached homes.

Allowing them would "immediately open up significant new opportunities for both denser and more affordable forms of housing. Stacked townhouses have become one of the most popular and preferred forms of housing in London, and in many cases, this type of dwelling has become our new form of a 'starter home,' Morgan wrote in a letter to city councilllors, adding that they're "highly compatible with all other types of residential land uses."

Under new strong-mayor powers, Morgan does not need a majority of city councillors to agree to the new rules. The change, if it goes ahead, would permit an extra storey to be built on connector streets, because currently only three-storeys are allowed.

"Nobody in our neighbourhood received notice. It shocked us and it upset us," said Andrea Lukac, who would like to see neighbours give more input on whether stacked townhouses should be allowed.

"We understand the need for densification but it's essential that neighbourhoods like Old North are respected. We need to keep the spirit of Old North. These streets have already undergone change in the form of bike lanes, increased traffic, more transit. Can the infrastructure even handle it?" Lukas said.

City councillors Sam Trosow and Corrine Rahman will be among some who will opposed the mayor's idea on Tuesday.

"Stacked townhouses can be a very appropriate planning tool on many city streets. I'm looking at the neighbourhood connector (streets) in my ward and thinking, 'Hey, it can work here, but it cannot work here.' Just to say that they should be allowed on all connector streets, that doesn't make sense. Developing the parameters should be the subject of a separate staff report and then public input," Trosow said.

Residents are upset because they didn't know such changes were coming, Trosow and Rahman said.

"People moved to this street, for example, expecting a certain character, seeing the plan for the subdivision and what it will look like, and to now change it without public consultation, to something that could affect property values, that is a problem," Rahman said on Tokala Trail in the city's far northwest. Tokala Trail is a neighbourhood connector street but is not labelled on the city map.

There are residents, however, who welcome more density to their neighbourhoods. Ben Johnson has lived in Old North for a decade and says the opposition to stacked townhouses reeks of NIMBYism and snobbery.

"I definitely see that this has been rushed through but I don't understand the argument opposing population density in our neighbourhood," he said. "We all agree that housing is a major issue in London and we need more places to live. Other than an argument that stacked townhouses would probably bring people with lower incomes than the current demographic into our neighbourhood, I'm not sure what the opposition is. It reeks of a little bit of elitism."

Having more people in a neighbourhood allows it to thrive, Johnson said.