When wildfire risk shaped a project, it reshaped what Kim Walton knew about home design, including her own.
Twenty years ago, Walton saw the future we’re now living in. Back then, grassfire embers fell near her home. This year, there were grassfires in March, pushed by 80 km/h winds. What once felt like a rare threat is now becoming routine. In a province now familiar with wildfires and grassfires, gusting winds, and weeks of smoke-choked skies, the fire season is no longer a season, it’s an unwelcome feature of life.
Across Canada, more homes are being built in the wildland-urban interface, places where dry brush meets housing tracts, and where policy hasn’t caught up to the new math of risk. As climate volatility grows, the safest buildings are not the ones that meet minimum standards but the ones that exceed them.
Thomas Walton Photography
The Canmore Lesson
For Walton, principal of Bow Crow Design and a Passive House designer with more than four decades of experience, fire resilience had always been on the periphery. That changed with a recent high-performance home she designed in Canmore, in an elevated-risk zone in Alberta’s Bow Valley. The project, intended as a resilient energy-efficient build, became a crash course in new ways of building that has left a lasting imprint on her professional and personal life.
“I’ve been doing this for well over 40 years, and when I learn something new, I’m always kind of astounded that I didn’t know this before. But there you go.”
What surprised her most? The soffit vent. It’s one of the most vulnerable points in conventional construction. It’s a vent at the roofline that most would overlook, but in a fire it acts like a funnel for wind-driven embers.
“Once fire gets into the insulation,” she says, “the house is done. You can’t stop it. It’s in the roof, and it takes off too fast.”
Walton now specifies soffit vents that seal shut under high heat or recommends low-cost fire-resistant mesh screens that prevent ember intrusion. It’s a small fix that she believes should be standard in building codes.
That wasn’t the only upgrade. For the Canmore project, she decoupled the mass timber and bamboo deck from the structure so it could fall away in the event of fire. She layered metal cladding over mineral wool, creating a non-combustible, ember-resistant skin. The walls used dense-pack cellulose delivered through prefabricated panels. Air intakes were protected. Windows were triple-glazed and tempered. Even mechanical systems were tucked safely inside the thermal envelope.
Additionally four cisterns under the deck collect rainwater from the roof. The water will be used for watering plants as well as for fire protection. The skirting for the deck itself is clad in fire resistant metal.
Much of this, Walton says, she learned through client collaboration, field research, and case studies out of British Columbia and California. It wasn’t part of the training. It wasn’t part of the building code. But it should be.
“The reality is we aren’t protected,” said Walton after taking a crash course in fire resilience and realizing our political and industry leaders have failed to protect us from the fire threat. “That’s a big surprise.”
While clients with means rarely hesitate to invest in resilience, Walton noted the need for insurance incentives and code updates to make these protections standard not optional.
Walton’s Canmore project echoes advice of fire safety experts like Birgitte Messerschmidt, Director of Research at the National Fire Protection Association in the U.S. She said in a recent Passive House Network webinar that the primary wildfire threat to homes is not the fire itself but the embers it generates, responsible for igniting up to 90% of structures lost in wildfires.
She said that resilience must start with preventing ember intrusion through ember-resistant vents, ignition-resistant materials, and creating noncombustible zones.
Beyond individual buildings, Messerschmidt called for systemic property-level strategies: maintaining a 0–5 foot noncombustible zone around the structure, eliminating flammable landscaping and wood fences that connect directly to buildings, and ensuring ongoing maintenance through community-wide programs.
“We’ve got to make sure that when those embers come in and they land around the building there’s nothing to ignite,” said Messerschmidt.
Resilient Passive House Design
Before adding fire-proofing measures, a Passive House design delivers a range of resilience benefits. High levels of airtightness don’t just conserve energy; they also block smoke, embers, and heat. Continuous insulation prevents weak points.
“If air can’t get in, water can’t get in, fire can’t get in,” Walton said. She highlighted the Passive House Certified Wood Innovation Research Laboratory at UNBC as an example. In 2023, a natural gas explosion destroyed an adjacent building, but the WIRL survived the blast due to its flexible mass timber frame, which absorbed and rebounded from the force; its independent, easily replaceable exterior panels; and its floor joists filled with fire-resistant mineral insulation that helped block heat and flames, UNBC said in a story on their website.
The Passive House Network’s Safe at Home white paper cites some recent papers that further back up the resilience of Passive House buildings (outfitted with HEPA filters) are effective at stopping infiltration of outdoor air pollutants like PM2.5 which spikes during heavy smoke events.
Another highlighted study found that Passive House buildings maintain habitable indoor temperatures for over six days during outages, more than double the resilience of code‑built homes. Similar analysis presented at our Passive House Canada Conference in 2022 in Victoria found that a mid-rise Passive House building in a cold climate was the best at maintaining thermal comfort during prolonged power outages, staying comfortable for 60% of a year without any active heating and/or cooling system.
Credit: Aylin Ozkan & Joel Good, RWDI
Following the 2021 B.C. heat dome that caused 619 deaths, 98% of them indoors, the BC Coroner’s report recommended expanding rebates and updating building codes to require both passive and active cooling.
After the January 2025 wildfires devastated communities across Los Angeles County, the region’s costliest climate disaster to date, the Blue Ribbon Commission on Climate Action and Fire-safe Recovery recommended advancing Passive House design. The commission said officials should expand education on the benefits of Passive House for resilience, sustainability, and health, and by streamlining its adoption by fast-tracking “pre-approved designs for fire-resistant, all-electric homes (e.g., Passive House).”
Resilience Comes Home
Walton began her career as a building designer in the 1980s, working from rural Alberta. One of her first jobs was with a log construction firm that required precise detail for prefab systems. That experience shaped everything that followed. “I wear a lot of hats in every project,” she says. Walton typically leads concept design, energy modeling, construction drawings, and material selection, while also supporting contractors during the build. Her approach is rooted in practical coordination: bringing everyone to the table early to design buildings people are actually able and willing to construct.
Now, that same pattern of learning new skills, taking on new roles is being applied to climate resilience – for her clients, and for her own home.
Walton is currently renovating her rural Alberta house with fire in mind: triple-glazed and tempered windows on the lower floor, mineral wool insulation over the exterior, metal siding to replace flammable cladding, and deliberate attention to overhangs and soffit detailing.
“We thought we had a well-sealed house when we built in the 1980s,” she said during our conversation. “But knowing what I know now, it absolutely needs to be updated.”
Walton is updating the home not just for efficiency, but so it can serve as a climate-safe refuge for her family in the decades ahead.
In the absence of policy, it’s people like Walton who are quietly redrawing the edge of what a home can do, and who are building the code the rest of us will eventually follow.
