The large majority of funding programs related to sustainable building are tied to a reduction in operational energy usage and greenhouse gas emissions. This leaves the sector with much less energy (pun intended) to put towards carbon reduction in the construction phase of development. We were curious about what is being practiced in sustainable construction currently and what the future may have in store for the sector. So, we chatted with a few of our neighbours for some insight. Read on for two short summaries of conversations with industry experts Anthony Leaning and Brad Rodgers.

A discussion with Anthony Leaning, CSV Architects

In last month’s blog post, ‘Discussion Panel – Building Green Recap’, we defined embodied carbon. Once again, according to the Canada Green Building Council, “[e]mbodied carbon refers to the carbon emissions associated with materials and construction processes throughout a building’s life cycle”. However, that blog and panel focused more on how we plan for decreasing carbon reliance during operations. In a conversation with architect Anthony Leaning (CSV architects) earlier this month, we wanted to inquire more about those upfront materials and construction practices and how builders are addressing embodied carbon. Leaning is a leader in the sustainable design space with over three decades of experience working on increasing energy efficiency and green building.

He humbly noted that while CSV has a strong sensitivity to more sustainable practices, reflected in some of the materials they choose (and their commitment to professional development on the topic), they have yet to dive deep into a project that deeply focuses on embodied carbon reduction at the construction phase. Collaboration is essential, and clients should actively encourage architects to address embodied carbon. While architects often must prioritize cost-effectiveness in affordable and public sector projects, Leaning anticipated an opportunity to delve deeper into this issue with the right client.

Some of the Athena Institute’s work includes Life Cycle Analysis (LCA) advocacy, software tools and disseminating key data.

So what is LCA anyway? LCA is a quantitative tool that is used to measure the environmental impact of a building project from construction to demolition. It can assist in making more informed and environmentally responsible design decisions. As Athena puts it, “LCA looks at the upstream and downstream burdens throughout the entire building life cycle, with a focus on embodied environmental impacts.”

Various lower-impact decisions can be made in the design and construction phases. Exploring various case studies provides insight into the practices adopted. Notably, some choices may involve using low-VOC paints and finishes, eliminating specific materials, and incorporating reclaimed or recycled resources. Leaning highlighted the growing availability of lower-carbon materials, which is encouraging.

Regulatory frameworks are also slowly moving towards enabling sustainable building development. For example, Leaning reminded us that wood construction has less embodied carbon than concrete. Meanwhile, the construction industry is also moving in a positive direction. He noted that, “in Ottawa, it’s getting to the point where it’s competitive to consider wood building up to six stories”. The industry is actively responding by designing new enabling technologies to deal with challenges such as earthquake loads. Leaning also noted that, “there is a case where, by increment, the low-carbon choice is becoming attractive”. A large impact will be made by moving away from concrete.

Leaning described that, in the current landscape, it’s been an easier sell to clients to design for a reduction in operational carbon, as they will see cost savings down the line. Reducing embodied carbon is more challenging because of the higher upfront costs, with no promise of cost savings. As various stakeholders collaborate and enable better practices around reducing the lifecycle impacts of embodied carbon, these practices will likely become more and more affordable.

 

A discussion with Brad Rodgers, Dream Unlimited

We also had the chance to learn from Brad Rodgers from Dream Unlimited about his perspective on greener construction practices. Below is a summary of our interview with him.

In your experience, what are some innovative approaches or technologies that can help lower the environmental impacts of the construction phase of housing development?

  • Brad:Among other approaches, we find that targeting waste reduction can have a meaningful environmental impact during the construction phase. We address waste reductions with many strategies including on-site training for trades, establishing separate bins for recyclable materials and off-site sorting of waste. Additionally, we are introducing prefabricated wall panels on several projects to further reduce our construction waste during construction.”

Could you discuss specific examples of materials or construction techniques that have a lower environmental impact and contribute to sustainability goals?

  • Brad: “It’s no secret that reinforced concrete structures contribute significant embodied carbon emissions during the construction of high-rise buildings. We endeavor to reduce the embodied carbon of our structures by using less material by optimizing our designs (minimizing transfer slabs) and utilizing lower carbon alternatives to reduce our cement (GUL cement, using slag/fly ash etc.,). We also strive to source our reinforcing steel from North American steel mills which tend to create lower carbon emissions during processing and result in reduced transportation emissions.”

How can construction schedules be optimized to minimize environmental impact, such as working in specific seasons?

  • Brad: Each building site is unique, so we have to evaluate the site-specific conditions of each project to optimize the success of project. At Zibi, we often plan our construction to avoid the spring high water levels and associated dewatering. We also try to avoid placing large volumes of concrete in the winter due to environmental impacts and costs related to heating the building structure.”

What challenges do developers typically face when implementing climate-conscious construction practices in (affordable) housing projects, and how can these challenges be overcome?

  • Brad: “There’s obviously a cost premium associated with developing energy efficient and sustainable buildings. It can be challenging to make a project economically feasible when balancing the cost premium of sustainable buildings while also providing affordable housing. There have been many successful funding programs, grants and incentives that have supported the development of sustainable and affordable projects. Continued support from all levels of government will increase the number of projects that are able to integrate both climate-conscious construction and affordability.

 

Monthly Webinar: Navigating Embodied Carbon Modelling: Best Practices and Insights

Wednesday, July 31, 2024 at 12:00 PM – 1:30 PM (EST)

The Toolbox+ team are pleased to announce that we will be interviewing Stephen Pope, the Sustainability Consultant at CSV Architects and Board Chair of the ATHENA Sustainable Materials Institute for the next monthly webinar. When it comes to energy efficiency, carbon is the new metric for building performance. But how does carbon measurement relate to the operations of buildings? What does it mean for the planning of future buildings? We will explore the process used to document the climate change impacts of building construction and operations. Life-cycle assessments (LCA), which historically have been used by manufacturers to improve their products through dematerialization and manufacturing process improvement, are now being applied to buildings and building components.

Join us to see how carbon measurement can work for you as an operator and developer. Don’t miss out on this opportunity – register now here.

Want to learn about the Ottawa City Budget 2025 and what it means for housing?

Check out our up coming panel discussion here!