How building height limitations are contributing to Ottawa’s housing crisis

Toon Dreessen
Toon Dreessen
Editor's Note

This article is sponsored by Architects DCA


In 2020 the city of Ottawa declared a housing emergency. Issues of housing affordability and availability underlie this declaration. At the same time, the city declared a climate crisis and enacted a new Official Plan with a goal of increasing housing density within the urban boundary. 

But there is a disconnect between these density goals and the Official Plan. 

The new Official Plan (OP) limited height on minor corridors to four storeys instead of six in the downtown, inner urban, outer urban and suburban transects. In the inner urban area, for example, this includes Parkdale, Holland, Pinecrest, Gladstone, Kirkwood, Donald, Cummings and Churchill Avenues. Many of these are already home to mid-rise or taller buildings.

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By limiting development on these streets to four storeys, the city has virtually guaranteed that they will be undeveloped – because it’s not profitable unless it’s expensive housing. 

For example, a 30mx30m (100ft x100ft) infill property that contains one level of below grade parking, ground floor shops and residential units above makes a good case study:

  • At six stories you can get 50 residential units in the building, but at four storeys, it drops to 30 units. Costs are generally calculated by the return on the number of residential units. Spread over 30 units instead of 50, the cost per unit goes up.
  • Core costs for things like sprinkler, fire alarm and HVAC systems; elevators; parking/basement and servicing are effectively the same whether it’s 30 or 50 units. 
  • Planning costs for site plan approval, as well as timelines for review and approval are the same regardless of whether it’s a four storey or six storey building. 

With the cost of services and planning now shared by fewer units, expect the cost of construction for those units to go up from at least $350/sq ft to more than $450/sq ft.

These are core issues that the OAA Housing Affordability Report identifies as a barrier to creating more housing that is more affordable. This report specifically identifies opportunities for infill mid-rise development in corridors with options to improve affordability. With modular construction, we create greater affordability, accessibility and create more homes for families. 

This decision virtually guarantees that if housing is built on these streets, it will be luxury, high-end units, unaffordable to the average family. It’s more likely that the lots will remain undeveloped or will be underbuilt – defeating our goals of moderate intensification – sending more people to outlying areas or concentrating development in highrises on major streets. 

The rationale for reducing this height limit has been to reduce friction between detached homes bordering these minor corridors and the potential for development on them. This argument doesn’t hold water: development applications are subject to public input and there will be just as many complaints and delays for a four storey infill as there will for a six storey. What will result is more applications coming forward that challenge this height limit – demanding eight or 10 storeys – in part to help cover the cost of applications and years of delay through planning appeals.  

An argument used in favour of this decision is that four storey buildings will allow sustainable wood construction.  Again, this doesn’t hold up: at four storeys, while the buildings could be conventional wood frame (studs and joists) this is subject to incredibly high insurance premiums; it is also a slow construction process; developers are not interested in the risk and carrying cost for this scale of building. While mass timber construction is possible, there isn’t enough repeatability of the floor plate to make a four storey building viable. That same rationale applies to concrete or steel construction. There simply isn’t enough repeatability of a floor plate to make it worth building a four storey building. 

It’s unfortunate that leadership has opted to limit the moderate intensification we need on these streets. These minor corridors could create hundreds of homes and places for small businesses to thrive. They could provide sensitive, well designed, infill projects that show climate leadership.

Toon Dreessen is president of Ottawa-based Architects DCA and past-president of the Ontario Association of Architects. For a sample of Architects DCA’s projects, check out the firm’s portfolio at Follow @ArchitectsDCA on Twitter, Facebook, LinkedIn and Instagram.

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