By Jay Fox

Le Monarque, an eight-story residential development currently under construction on the outskirts of Sherbrooke, will soon bring 134 apartments of affordable housing to the midsize city in southeastern Québec. All the apartments are guaranteed to remain affordable for 35 years once they’re occupied, and the Sherbrooke-based nonprofit Le Parallèle de l'habitation sociale (Parallel Social Housing Inc.), which is developing the property, has included 16 two-bedroom and 16 three-bedroom units within building’s scheme.

In addition to creating long-term affordable units for families of varying size, the project team behind Le Monarque also decided to pursue Low Energy Building certification through the Passive House Institute (PHI). The innovative work by the design team led by architectural firm Équipe A, in conjunction with strong commitment from Le Parallèle de l'habitation sociale, shows that reaching this level of performance can be accomplished without significantly higher upfront costs than code-built construction and can bring numerous benefits to building occupants. As the case with Le Monarque shows, it can even be done on an accelerated schedule.

Connecting Sherbrooke

Sherbrooke is a mid-sized city located about 150 kilometers east of Montreal and 60 kilometers north of the Vermont border. It has a large student population because the city is home to two colleges (Cégep de Sherbrooke and Champlain College) and two universities (Université de Sherbrooke and Bishop’s University).

The largest of the four is Université de Sherbrooke, which has an enrollment that exceeds 40,000 students, and is divided into two campuses within the city limits: the Main Campus to the southwest of downtown, and the Health Campus northeast of the city, which houses centers for biomedical research, the city’s largest hospital, and clinical facilities that specialize in pediatrics and geriatrics. While the Main Campus has long been integrated with the city, the Health Campus sits well outside of any neighborhood and is only connected to the city via 12^th Avenue North, a major commercial artery.

However, Le Parallèle de l'habitation sociale did not initially set out to develop the current site of Le Monarque. Rather, they had qualified for funding to build on a nearby property. After months of planning, designing, and jumping through the many procedural hoops to work with and obtain funding through the Québec Affordable Housing Program, the project fell through.

Luckily, Le Parallèle de l'habitation sociale was allowed to submit plans to develop the current site for Le Monarque. The catch: there were only six months left on a twelve-month schedule. The architect with whom they had been working could not continue the project, so Le Parallèle de l'habitation sociale engaged Équipe A to design an entirely different building.

Despite working on such an accelerated timeline, Équipe A was able bring together a team that included all the professionals and contractors they needed to start building. They then utilized BIM with Revit and Autodesk Construction Cloud to optimize workflow and create a transparent and truly cooperative workspace. As Équipe A Architect Vincent Bergeron-Marier explains, “Having constructed a digital prototype of the building, we were able to anticipate a lot of issues and to solve complex problems fairly quickly and easily.”

In addition to using these technologies, Bergeron-Marier says that the project team (see above) had worked together in the past, and that they had built a mutual respect for one another. “The result is a super efficient and collaborative work environment,” he says.

Passive Enters the Equation

“Passive House was not something we were aiming for first,” Bergeron-Marier says. Québec has lagged behind other provinces in Canada, particularly Ontario and British Columbia, because energy is so cheap and the grid is so clean due to the abundance of hydroelectric power. As a result, there are relatively few firms in the construction sector who prioritize going beyond code with respect to installing insulation and air sealing. No surprise, this means fewer buildings that meet Passive House standards.

Though Passive House was not on the table, the team recognized gaps in funding for the project that the team needed to fill as they scrambled to submit their final plans. The client encouraged the design team to think outside of the box and to apply for any grants they could to help finance the project. One of the mechanical engineers who works with Akonovia and specializes in energy efficiency, Raphaël Boisjoly, recommended Passive House certification.

Boisjoly is no stranger to the standard, as he is a member of Passive House Québec (Bâtiment Passif Québec), and he convinced Bergeron-Marier to bring the idea to the attention of Associate Architect Olivier Bousquet, who was the point person with the client. Bousquet did not take much convincing, and they set to work making a proposal for Le Parallèle de l'habitation sociale.

“The client had no clue what Passive House meant,” Bergeron-Marier says, but they were receptive to the goals of Passive House so long as the numbers made sense. “‘Does it work financially? Will it create a better environment for the tenants?’” the client asked. “Yes? Then okay, I give you my approval,’” Bergeron-Marier says. “She really trusted us.”

“Being a nonprofit organization, the client really had to make sure that it made sense and that it was not just labeling—that it would give something back to the tenants. But it’s not one of those certifications that’s really prescriptive, where you’re just taking the list and checking boxes,” he continues. “It’s more holistic and really aims at making sure that people are comfortable and that people spend less on energy bills.”

Orienting for Community

In addition to the eight stories above grade, there are two levels below grade—at least from the vantage point of the street. These floors contain parking and utility rooms. As shown in the rendering (Figure 1), occupants access the upper level of the parking lot from a side entrance or the lower level of the lot from the back of the building. As is typical with buildings where parking is included on the lower floors, the garage is not included within the Passive House envelope. “We didn’t want to put money into the comfort of tenants’ cars,” Bergeron-Marier says.

What may come as a surprise is that the building’s orientation was influenced more by the site’s topography than an attempt to optimize solar gains. There is a notable slope as one moves away from the access road, and Bergeron-Marier notes that the original orientation of the L-shaped building created an internal courtyard that looked toward the protected stream. By flipping the orientation 180 degrees, the building’s courtyard becomes open to the public and the basement levels can be tucked neatly into the slope on the property.

The client was particularly happy with the creation of the public space, which will become a playground with a small park. The hope is that the playground will cultivate a family-friendly environment within Le Monarque, encourage more engagement with the surrounding community, and contribute to the burgeoning social fabric along the 12^th Avenue North corridor.

Panelization and the Passive House Enclosure

The use of prefabricated panels is another strategy that has proven vital to meeting priorities involving costs and scheduling. Bergeron-Marier explains that panels are steel stud assemblies that are used to construct the exterior walls and interior partitions within the building’s concrete structure. The prefabricated sections in the interior are limited to the studs themselves, while the exterior includes the framing and exterior sheathing. The sheathing is a fiberglass mat with a gypsum core on which the air and vapor barriers (both by 3M) are directly attached. These panels extend beneath the concrete slab of each story and then connect to the panel directly below. In keeping with the perfect wall system developed by Joe Lstiburek, a layer of exterior continuous insulation is installed, followed by the cladding system.

What is perhaps most impressive is that each section is designed to be handled by two workers who can install the panels from the inside, eliminating the need for scaffolding. According to Bergeron-Marier, this innovative process doesn’t just save money; it also gets the building airtight as quickly as possible and cuts down on waste because the studs are all produced to a set length and do not need to be cut on the jobsite.

Though the decision to use panelization predates the decision to pursue Passive House certification, the team was relieved to find that only minor modifications were needed to get the enclosure’s performance to Passive House levels. The continuous insulation layer was already designed to be installed externally and on site, as the wall assembly is based on the perfect wall concept, and increasing the thickness of the layer was not particularly difficult. They ultimately used 8 inches of Cavityrock by ROCKWOOL through which they installed thermal masonry anchors for areas with brick cladding and ACS thermal clips from Soprema for sections on the upper floors where the cladding is aluminum. The assembly results in an effective R-value ranging from R-32 and R-38.

The team also used ROCKWOOL Comfortbatt in other cavities that needed to be insulated, including duct and pipe penetrations, as well as along the parapets. For the roof assembly, the team opted for a system that includes a 16-inch layer of polyisocyanurate beneath Soprema’s Mammouth Neo One, a single-ply membrane composed of biobased thermoplastic polyurethane polymer-modified bitumen that is covered by a 40-year warranty. The assembly has an R-value of 93.

For the glazing systems, the team was able to find a local manufacturer, Isothermic, to supply windows and doors capable of meeting Passive House performance levels. They also worked with a local glass manufacturer Prelco, and a curtainwall manufacturer, Prevost, to create vacuum insulated glass units that offer even better performance levels than triple-pane windows. As shown in the renderings above, the use of curtain walls is limited to the lobby on the ground floor.

Bergeron-Marier specifically calls out the structural engineer Michaël Jean of Côté Jean et associés for performing nothing short of a “magic trick” when designing the inset balcony. Jean created an assembly of galvanized steel plates that are installed within the balcony and the exterior wall, and then connected through Nelson studs, which the architects can easily fill with polyurethane. Polyurethane was chosen because of the material’s high R-values (R-6.6 per inch) and due to limited space. The result is a thermal break to separate the concrete floor plate and the balcony (see Figure 2).

Jean refers to the connection as the “Bataclan,” and Bergeron-Marier says that it can be replicated by any steel fabricator. Moreover, installing the Bataclan does not require a strictly regimented sequence of pouring concrete. The team can cast the interior slab, and then immediately do the balcony. They can also wait. The concrete crew especially appreciates this level of flexibility.

Planning for Resiliency

“Going Passive House is also a question of resilience,” Bergeron-Marier says. Even though Sherbrooke is located in Climate Zone 6 and experiences winter lows that reach -30°C (-22°F), summertime highs oftentimes exceed 30°C (86°F). The summer is also very humid. Should the grid fail in either season due to extreme weather conditions, the results can be fatal for individuals in code-built homes. Conversely, homes built to Passive House standards can remain comfortable for days without electricity to power the active cooling or heating systems due to thermal massing of the building.

Within Le Monarque, these systems will be provided by a split air/air heat pump system with backup electric resistance heat sources. The domestic hot water system will use Mitsubishi ECODAN CO2 heat pumps that will be situated on the roof as the primary source of hot water. The system will have a backup electric resistance hot water tank. For ventilation, the apartments will each be outfitted with Swegon CASA R4C compact air handling units. Bergeron-Marier notes that the boost mode on the unit is critical for balancing pressure when exhaust rangehoods or dryers are operating.

Heating, cooling, and fresh air will be supplied to the common areas through a separate system that includes ceiling VRF units and a Swegon F RX Sorption 11 that is being installed on the roof. The system that supplies conditioned air to the common areas will also be connected to a solar wall (the darker section of the southern elevation directly above the lobby in Figure 1) that provides additional preheated fresh air to the system. As Bergeron-Marier explains, the dark metal paneling of the solar wall is equipped with “microperforations” and a duct that pulls outside air into a space that sits directly behind the wall. Solar radiation then preheats the air within the cavity before it is mixed with the supply air to the common areas during heating season.

The systems that supply the common areas and the dwelling units are separate because those who live in social housing in Québec pay for their heating and cooling. While there are pros and cons associated with any system, Bergeron-Marier says the decision produced two notable benefits for the client. First, the lack of ducting allowed them to have lower floor-to-floor heights, which reduced costs on insulation and other materials throughout the building, while cutting down on the need for fire dampeners, which can be expensive.

As yet another benefit, energy models indicate that building to Passive House standards will cut energy use by 83%. Even though Québec is known for its affordable energy, the reduction in use will result in savings of $750 annually for each unit. As Le Monarque will provide housing for many struggling members of Sherbrooke’s working class, these savings will be felt immediately.

Teamwork and Humility

Though construction is ongoing and occupancy is expected in 2026, Bergeron-Marier can provide a few pointers to project teams who are preparing to build their first Passive House. The first is relatively straightforward: “Stay humble,” he says. “You don’t have all the answers.”

Second, finding a solid team is paramount to success. It’s especially important to have at least one teammate who has worked on a certified Passive House project before. Contractor Construction Longer has been especially helpful, Bergeron-Marier says, because everyone on site understands Passive House and the firm keeps the checklists accompanied by photos for every step of the building sequence. Even though this seemed like overkill to some workers, they eventually started to appreciate the level of precision involved in the construction of Le Monarque and have become intensely proud of what they are doing.

The teambuilding work is paying dividends. As of late spring, preliminary tests with the smoke stick suggest that the panels are as airtight as they were designed to be. Only a few cosmetic changes have been needed so far.

Finally, he advises designers to keep an open mind and to use modeling data and the experience of others to question their preconceptions. “If you're looking to build a Passive House project, don't be dogmatic,” he says.