Envelope detailing meets Passive House standards Design Partners in Architecture and Interiors (DPAI) was engaged by Effort Trust to design and detail a nine-storey purpose-built rental apartment building in Dundas, just outside Hamilton’s downtown core. Early in the project, DPAI led an extensive neighbourhood consultation process, advocating for a high level of sustainability. As a result, and given the operational savings and access to grant funding, the client chose to pursue Passive House Canada certification.

By Petra Matar

To reduce construction costs and timelines, construction manager Legacy Constructors proposed a total precast system. DPAI collaborated closely with Stubbe’s, the precast manufacturer, to develop a façade design complementary to this construction method. Panel-to panel joints were concealed through strategic façade reveals, creating a clean, repetitive panelized language. Variation in surface textures introduced colour shifts between panels, reducing the need for extensive painting and simplifying long-term maintenance.

Achieving a high-performance thermal envelope was a primary goal. Working with sustainability consultants RDH Building Science and Stubbe’s, we designed a thermal-bridge-free enclosure. Insulated double-wythe precast concrete panels were used to minimize thermal bridges between the cladding supports and interior slabs. High performance phenolic foam insulation (R-8.4 per inch) was specified instead of typical XPS insulation (R-5 per inch) to further enhance energy efficiency. The interior wythe was increased to six inches on cladding walls to eliminate most insulation notches. Additional spray foam at panel joints ensured continuous insulation across the façade. 

To eliminate thermal bridging between the inner and outer wythes, fiberglass shear tie connectors replaced conventional steel ties. Early in the design process, balconies were modified to be inset, and through close collaboration with Stubbe’s, they were engineered to bear directly on the outer wythe, creating a fully thermal-bridge-free balcony system.

Through close coordination among DPAI, Stubbe’s, RDH, and Legacy Constructors, the building achieves an integrated design that is highly energy-efficient, cost-effective to construct, and simpler to maintain over its lifecycle, while aligning with the strict standards of Passive House certification.

PETRA MATAR OAA, MRAIC, CPHD IS PRINCIPAL AT DESIGN PARTNERS IN ARCHITECTURE AND INTERIORS.

TOTAL PRECAST MINIMIZES MATERIALS
By Devin Baty

The building is constructed using a total precast concrete structure, ensuring longevity, stability, and a solid investment for years to come. Precast concrete is known for its superior strength and resistance to the elements, making it an ideal choice for this new landmark in Dundas.

The use of hollowcore slabs for excellent load-bearing capacity and precast concrete exterior walls for a resilient building enclosure minimizes the use of materials, thus aligning with Centurion’s dedication to sustainability.

In today’s environmentally conscious world, energy efficiency is more important than ever, and Centurion’s development at 71 Main Street embodies Passive House principles by incorporating state-of-the-art energy-efficient systems that reduce both energy consumption and residents’ utility bills. These systems are designed to work seamlessly with the building’s precast concrete structure, creating an environment that is both comfortable and sustainable.

From high-performance windows that reduce heat loss to advanced HVAC systems that ensure optimal indoor air quality, every aspect of the building is designed with energy efficiency in mind. All windows were installed in Stubbe’s climate-controlled factory before being delivered to the site. This commitment to Passive House standards not only benefits the environment but also enhances the quality of life for residents.

DEVIN BATY IS CHIEF ESTIMATOR AT STUBBE'S PRECAST.

Precast concrete components

• 4,545 sq.m (48,900 sq.ft.) of 200 mm (8 in.) hollowcore floor slabs
• 528 sq.m (5,680 sq.ft.) of 250 mm (10 in.) hollowcore floor slabs
• 234 sq.m (2,520 sq.ft.) of balcony solid slabs
• 6,505 sq.m (70,020 sq. ft.) of precast concrete walls
• 36 133 sq.m (1,430 square feet) precast landings
• 48 (458 risers) precast stairs
• 2.4 metres (8 linear feet) of tee beams

Photos courtesy of Stubbe’s Precast