Building Enclosure Renewal Project

The Belmont gets a cost-effective building envelope retrofit

Aging buildings throughout Canada continue to pose both challenges and opportunities, as government, architects, designers, owners and building operators examine strategies for cost-effective retrofits of the building envelope. Upgrades must not only support increased building performance, but demonstrate favorable return on investment (ROI), while providing minimal disruption to existing residents.

The Project

The Belmont is a 13-story condominium building originally constructed on the west side of Vancouver, British Columbia, Canada, in 1986. Typical of its age, its building envelope was reaching the end of its functional service life. To address aging components, a building enclosure renewal project was undertaken in 2012.

The Problem

The retrofit needed to solve water penetration and durability issues, while improving comfort, acoustics, aesthetics and energy efficiency.

The Opportunity

In addition to addressing existing defects, The Belmont renewal project provided an ideal opportunity for collaboration among various levels of government, stakeholders and engineering consultants to study the impact of building enclosure rehabilitation on the energy consumption of mid- to high-rise buildings. The retrofit took place between May and December 2012, while monitoring, measurement, testing and verification of various performance indicators was undertaken throughout 2013.

The Solution

Implementing solutions that would support long-term performance and reduce ongoing energy costs was essential to The Belmont’s building envelope retrofit. Before the renewal, the existing exterior walls were comprised of exposed cladding with 2 inches of rigid extruded polystyrene foam insulation at the inside, with an overall effective R-value of R-4.

For the renewal project, the walls were over-clad with 3.5 inches of Milton, Ontario, Canada-based ROXUL Inc.’s CAVITYROCK stone wool insulation behind stucco and metal panel cladding. The cladding and insulation were held in place using fiberglass Cascadia Clip, which significantly reduce thermal bridging compared to a more traditional metal girt cladding systems. This assembly increased the overall effective R-value to R-16 for the exterior walls.

Exterior Insulated Rainscreen

• New Cladding Stucco and Metal Panels
• Fiberglass Cascadia Clip with 1-inch Steel Z Girt
• 3.5-inch CAVITYROCK Insulation
• Vapor Permeable Coating
• Existing Concrete

CAVITYROCK stone wool insulation was ideal for the application given its natural hydrophobic properties, vapor permeability, and superior drying potential, providing functional benefits beyond dependable thermal resistance and effectively addressing critical deficiencies. Moreover, its dense non-directional fibres provided excellent sound-dampening qualities, while its high melting point

provided vital fire resistance and safety advantages. Its stability under wide temperature variations, resistance to mold, fungi growth, and corrosion, excellent dimensional stability, and environmental sustainability also influenced its specification in the rainscreen system. Window replacement and airtightness improvements were also made to the enclosure.

The Result

Energy savings as a result of the enclosure renewal project were estimated through whole building energy modeling, and are predicted to be a 20 percent decrease in overall building energy usage and 90 percent for in-suite space heating energy. This retrofit is expected to nearly eliminate the need for electric baseboard heating and cut total building suite heating costs from approximately $18,000 to just $2,000 per annum. In addition, greater thermal comfort has been reported by building occupants.

Conclusion

Ultimately, the project serves as a template that can be applied throughout North America, outlining an effective approach to sustainable, energy-efficient and economical building enclosure renewals of existing multi-unit residential buildings. The potential impact of such a model is significant, given the proportion of aging building stock in North America combined with the growing movement towards more sustainable and energy efficient building and retrofit practices.

Identifying upgrade opportunities-instead of replacing failed components or assemblies with similar alternatives that meet today’s minimum code-is an opportunity to provide valuable performance enhancements, long-term ROI to owners and operators/managers, while improving occupant comfort and raising the bar on the built environment. As existing buildings age, architects, designers and specifiers should see this as an important step in exacting positive and pivotal change.

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Kim Friedrich is segment manager, building insulation-commercial at ROXUL Inc., Milton, Ontario, Canada. To learn more, visit www.roxul.com.