High quality insulation is central to passive construction, creating an optimal indoor climate by minimising the need for active heating and cooling. Depending on the climate zone, houses built in Canada will likely need between three and seven times better insulation performance than that provided by current national and provincial Building Codes, in order to achieve Passive House performance. ROCKWOOL stone wool insulation products were used extensively to achieve a building envelope that could meet the strict Passive House energy requirements, resist moisture and provide excellent drying potential of the wall assembly. ROCKWOOL Comfortboard® 80 blanketed the exterior of the modules to form a continuous layer of insulation that serves to reduce thermal bridging and provide excellent sound control that’s important in multi-unit construction. In the assemblies between party walls, two layers of ROCKWOOL SAFE’n’SOUND® were used in combination with Type X gypsum to achieve a 45-minute fire separation rating.
“Modular construction proved the right choice for this particular project and provided several distinct advantages,” says Craig Mitchell, Director of Innovative Solutions, Metric Modular. “It cut construction time significantly, allowing us to deliver on the short seven-month timeline, whereas a conventional site-built complex would have taken close to two years to complete. Modular construction is also well-suited to accommodate a lot of Passive House details within a manufactured environment and allow air testing to take place in a controlled setting. Importantly, we also avoided the extreme weather conditions which would have created significant challenges on site. Finally, modular construction kept labour and site work costs in check in order to meet budgetary goals.”
In the end, modular construction achieved a super-tight building envelope in a controlled setting, delivering on precise quality and efficiency standards. The Bella Bella complex demonstrates that quality, cost-efficient, safe, durable, resilient and sustainable housing is possible to achieve in remote Canadian communities, accommodating harsh conditions and short construction seasons. The benefits are tremendous, allowing for greater thermal comfort, better indoor air quality, superior sound absorbency, and exceptional energy efficiency. The building’s simple mechanical systems require little maintenance, while its high mineral wool insulation levels reduce heating and cooling costs, increase drying potential to inhibit mold growth, while reducing reliance on expensive fossil fuels.