Less Is More: Engineering for a Smarter Use of Resources

Think Wood: What sets Holmes apart as a firm?

Adam Slivers: Holmes started in New Zealand in 1956.  I think these origins bring to the global company a culture of innovation and performance-based design. New Zealand has its own building codes and specific interests in seismic and fire performance. The building and construction sector in New Zealand is made up of a relatively small number of smart, driven companies and professionals that want to push good design into their codes. So as a firm, we excel at performance-based design in the industry and at Holmes, there’s a strong focus on high-performance earthquake resistant, fire safe and resilient design. I believe that unique regional experience benefits our wider global operations.

What are some of the things you’re doing as a firm to address carbon reduction and sustainability?

Building only what we need is the obvious choice to conserve resources, and a big part of our philosophy as it relates to sustainability. This is why we made modernizing existing buildings a major focus of our firm. We also signed up for SE 2050, focusing on embodied carbon in design. SE 2050 is an initiative where engineers commit to designing buildings that are carbon neutral by the year 2050, along with putting in the work to really measure the carbon footprint of projects. We educate ourselves and share that knowledge within our office, and we do advocacy. I sit on the Carbon Leadership Forum, which started at the University of Washington as part of their Regional Hub initiative. We do monthly presentations on various work and products, sharing resources and learning about industry trends. And supporting clients on mass timber and low-carbon materials is a cornerstone of our sustainability efforts as well. I personally work on our embodied carbon action plan, ensuring our project teams perform life cycle assessments (LCAs) and upload data to the SE 2050 database. 

How are LCAs contributing to a better understanding of sustainable material selection?

It’s about making smart, efficient choices in design and using LCAs as a decision-making tool. Often, key decisions are made before we’re engaged, but we focus on smaller levers like optimizing concrete cement ingredients. Efficient material use is fundamental in engineering, such as reducing concrete toppings over CLT to the minimum necessary. This simple adjustment can incrementally impact the overall weight and structural requirements of a building. Our annual report to SE 2050 ensures project teams perform LCAs, and now that SE 2050 has 500 data points, we can benchmark and strive to design buildings with lower carbon footprints per square foot. It’s about making smart, efficient choices to minimize waste and improve sustainability.

What is your experience with modular construction—and how do you think industry can take advantage of light-frame and mass timber construction in combination with more prefabricated methods?

Before joining Holmes, I did work for Katerra. And while the overall business model didn’t work out, there were some important learnings I gained through that experience. At Katerra, I worked on a 24-unit, three-story garden-style apartment in Tracy, California, which served as a pilot project for a light-frame modular panelized building system that could be implemented nationwide. This project was fully designed and coordinated in-house, with MEP systems assembled in a componentized manner and turned into shop drawings for panelized fabrication. The process involved automated CNC routing for plywood and saw cuts for lumber, while assembly remained manual but highly organized. 

The project helped show light-frame wood construction, especially when combined with modular and prefab technologies, is highly efficient in material use and quick to build. While mass timber has its advantages, such as carbon sequestration during a building’s lifespan, it’s important to balance resource use. For instance, most garden-style apartments don’t need mass timber and can effectively meet design, engineering, and fire requirements faster and more efficiently with light-frame wood construction. We need to aim for a wise and effective use of resources to maximize benefits. Sometimes less is more.

That’s a great point. What are the biggest challenges and opportunities where mass timber is concerned?

Designing cost-effective and constructible buildings—the mass timber industry is maturing but is still relatively young, and supply chain issues can make things challenging. At first blush, mass timber can seem more expensive and hybrid systems that bring in timber, concrete, and steel can seem more complex. A good relationship between architect and engineer can go a long way to overcoming those challenges. And educating the whole design and construction team is crucial to make the most out of mass timber and to realize cost savings—ultimately through faster, more streamlined processes. For example, on a recent project we determined that a mass timber project could be delivered two months quicker than a concrete one, with less than a half percent difference in material costs. Interestingly, the timber was said to be a bit cheaper, which is promising. This shows that, with the right approach, mass timber can be a viable and efficient option for projects like speculative office buildings.

What are you most excited about when it comes to mass timber and sustainable design? What trends are you tracking?

Building for circularity is really growing in importance—designing buildings so materials can be reused or recycled at the end of their life. Currently, when our buildings reach the end of their life, they most often end up in landfills—everything in this room we’re sitting in now will face that fate eventually. This must change. Our consumption, and humanity’s consumption, needs to focus on efficiency in design. For example, a mass timber panel used for flooring could be reused if designed with future use in mind. We must create smart ways to design for disassembly and use materials that manufacturers can take back. If a carpet isn’t recyclable, how can we make it so, or stop using it? Using natural materials or minimally upgraded ones can greatly enhance their life cycle and sustainability.