Small-scale infill, big impact: How it adds to housing supply in Canada

What counts as small-scale infill?

In this analysis, we build on a recent CMHC report on “missing middle” housing in Canada’s largest markets. Here, we take a closer look at small-scale infill, a type of housing built within existing neighbourhoods. We define small-scale starts as:

• buildings with 2 to 8 units
• accessory dwelling units

What does infill development look like in Canada?

This analysis combines housing starts data with historical satellite imagery to identify which projects are built on infill sites versus undeveloped land. This approach helps better track how much new housing is built within existing neighbourhoods.

Most new housing in Canada is built through infill rather than on undeveloped land. In 2025, about 6 in 10 new homes were built on previously developed sites (Figure 1).

Between 2016 and 2025, there was a modest 5-percentage-points shift away from building on undeveloped land. This trend likely reflects:

• limited land available for new development in major urban areas
• policies that support building more homes in existing neighbourhoods

In practice, this means more apartments and other multi-unit housing are being built on land that was previously developed at lower density.

Small-scale infill is growing, even as housing gets denser overall

Looking at different building sizes, 2 trends stand out:

1. new housing is becoming denser in all locations, and
2. ground-oriented homes make up a smaller share of new construction (Figure 2)

This is especially the case for single-detached housing starts, which have fallen since 2016.

The outlier within ground-oriented housing is small-scale infill. Its share of total housing starts was falling until about 2023, before rising sharply to surpass 2016 levels.

The timing of this reversal coincides with the launch of the Housing Accelerator Fund, as well as municipal and provincial reforms, such as Bill 23 in Ontario, and Bill 44 in British Columbia. Together, these changes allowed more small-scale infill housing to be developed on lots that historically contained a single home.

In 2025, small-scale infill accounted for nearly 1 out of every 10 starts nationwide.

Figure 2: Estimated Indexed Share of Housing Starts in Canada (%) by Dwelling Type and Location

At the same time, construction of larger buildings with 9 or more units have grown in prominence. In 2016 they comprised 42% of total starts, rising to 63% by 2025.

This demonstrates that densification is happening at scale, including on previously undeveloped land. Multiunit housing is playing a central role in driving new supply by concentrating multiple dwellings within single developments.

As-of-right zoning changes support small-scale infill

A growing number of Canadian cities have introduced zoning changes that allow more homes within existing neighbourhoods. “As-of-right” refers to development that complies with existing zoning permissions and can proceed without additional council approval or rezoning.

This can take many forms. Edmonton, for example, now allows builders to construct up to 8 units on a typical residential lot. Vancouver and Toronto have also adopted similar policies as-of-right.

In these 3 cities, small-scale infill has accounted for a growing share of housing starts (Figure 3). Following zoning reforms in 2023, the estimated number of new starts of this type increased several-fold in the first 2 years.

Much of this redevelopment occurred in neighbourhoods with older homes, close to the downtown core.

Where small-scale infill is growing fastest

CMHC’s analysis suggests that Metro Vancouver is a leader in small-scale redevelopment when measured relative to its existing stock of detached homes. The City of Vancouver is estimated to have one of the highest redevelopment rates in 2025, at nearly 1%. Nearby Metro Vancouver municipalities also show high levels of activity.

Edmonton and Calgary have also seen strong growth in small-scale infill. As shown in Figure 3, Edmonton had one of the highest shares of housing starts coming from small-scale infill in 2025, with more than 1 in 5 new homes built through this form of development.

This reflects both Edmonton’s large stock of detached homes and strong uptake of its more permissive zoning framework.

Uptake has been slower in Ontario overall, partly reflecting weaker housing starts in recent years. However, in places like Toronto, small-scale infill starts have still increased even during an overall slowdown.

Suburban areas with recently built housing show lower potential, as redevelopment is less likely where dwellings are newer and acquisition costs are higher.

Implications for housing supply

Small-scale infill is emerging as an important source of ground-oriented homes in Canada. This is happening even as overall construction trends shift toward larger multi-unit buildings.

Recent zoning changes are helping enable more “missing middle” housing forms in established neighbourhoods. Uptake, however, will depend on whether projects are financially viable for those delivering them.