How single-stair apartment buildings could be cooler, friendlier — and more affordable

B.C. is exploring the potential of allowing single-stair apartments under its building code, in a move experts say could help make affordable housing easier to build.

A single-stair or single-egress building features just one staircase and fire exit per floor.

Currently, across much of B.C., building codes state that most larger apartment buildings require two exit stairwells per floor — largely a product of fire safety regulations from decades ago.

On Friday, the province said it was asking consultants to submit proposals for single-stair apartment designs for buildings up to eight storeys high — which it says could allow for more multi-bedroom apartments and denser housing on smaller lots, and reduce energy costs.

"This work will focus on developing an understanding of if and how this innovation can be incorporated into building and fire codes," said B.C. Housing Minister Ravi Kahlon in a statement.

The province wants to see designs that can enhance safety and support access and egress at the same time, he said.

Alex Boston, a principal at Boston Consulting who works on housing, land use and climate, said a single-egress building would allow developers to cut out the corridor that needs to be installed in a traditional dual-egress building.

"This is a really great opportunity to address multiple priorities," he said. "Most importantly, managing cost, but also addressing climate and affecting beauty and social interaction opportunities inside a building."

The province's request for proposal states that they plan to select their contractor in February, with final deliverables expected in May or earlier.

Kahlon said the proposal was part of the province's strategy to build more homes, especially multi-unit houses.

'Like a bowling alley'

Russil Wvong, a member of the advocacy group Abundant Housing Vancouver, said most apartment layouts across North America are "hotel style," featuring a central corridor with a fire exit near each end and homes on either side.

"The issue with the hotel-style layout ... in order to make it work ... you need to have a fairly large building footprint," Wvong told CBC News. "You end up with quite a long distance between the hallway and the windows to the apartment. Someone described it as being like a bowling alley."

A graphic of a single stair apartment building and a dual egress apartment building shows the differences in how homes can be built, with the former allowing for a smaller number of net units per floor. (LGA Architectural Partners via B.C. Government/Flickr)

The fact most tall buildings need larger lot sizes is an obstacle for affordable housing developers, says Steven Hurst, director of real estate development at the non-profit Cool Aid Society.

"Small lots are often the only opportunity non-profit societies have to create new housing, but most can't accommodate a multi-family building under the current regulations," Hurst said in a statement provided by the province.

A woman sits on her balcony during a hot period of weather in Vancouver in July 2022. Most dual egress buildings have apartments that only have windows on one side, making cross ventilation difficult. (Ben Nelms/CBC)

Wvong said one of the advantages of single-stair buildings — which are allowed in cities like Seattle and New York — would be smaller projects that are more accommodating of multi-resident homes, allowing for lower carbon footprints.

"With a single staircase, [there's a] smaller number of apartments per floor. But it would be more social," he said. "You would see your neighbours much more often and get to know them."

More cross-ventilation possible

Boston said the larger apartments that are possible with a single-stair layout would also allow for more cross-ventilation, since windows could be located on different sides of individual units.

He says that could help prevent adverse effects during extreme heat waves.

"It's the single most cost-effective way to be managing the improvement of space conditioning in our buildings during the summer months," he said. "... This long corridor that's been required has forced us to compromise ventilation."

Boston said the designs calling for two fire exits per floor were well intentioned a century ago, but fire safety standards have caught up to modern building designs.

"We've iteratively strengthened our fire prevention through all sorts of different ways, from building materials as well as sprinkler systems, notably, that [allow] us more time to be able to exit a building safely," he said.

He said if single-stair designs are added to the building code, the province is likely to see developers moving rapidly to build the apartments.

He says builders, municipalities and the province should consider how best to maximize the positive aspects of the design, including allowing more natural light and maximizing cross-ventilation.