We know global climate change is one of the greatest challenges we face in the twenty-first century and our awareness of our impact in the AEC industry continues to grow. Powerful companies, influential people and future generations are asking us not to turn a blind eye to this crisis and to be part of the solution in protecting our planet. Providing both a healthy and habitable place to live for all needs to be a priority.

As a firm with footprints in California and Hawaii, we are faced with many challenges in these communities. Along with the challenge of addressing climate change – including rising sea levels, air quality, and our global carbon footprint, we are also leaned upon by many to address the homelessness crisis and lack of affordable housing. While many of our projects fall under the supportive and affordable housing category, the budget and economic sustainability for these projects is a constant concern. So how can we do both – build housing economically and design sustainably? Like our belief that good design does not have to be associated with high costs, meeting sustainable goals can be cost-effective and attainable when planned accordingly.

Practicing in states with the strictest energy and efficiency codes in the country, discussing building efficiency is a baseline of our practice. Our approach is informed by an understanding of economic and environmental impacts, and efficient natural resource utilization. To meet these requirements, we work with our clients and engineers to find the right systems for the budget and future goals of the project, and try to avoid costly solutions that eventually become economically inefficient. We also focus on strategies tuned to the local microclimatic conditions. With few exceptions, our California projects, at a minimum, are designed to be solar-ready, with solar photovoltaic panels and solar hot water. As part of our design practice, assessing building orientation is key in addressing the building’s efficiency, life span, and absorption of this natural energy source.

But beyond solar panels and sustainable materials, an increasingly pressing issue we face in the 21^st century in building is reducing our carbon footprint. As Earth Day approached, we wanted to dig deeper into the environmental impact of one of our greatest areas of specialties: modular design and delivery.

With over 5,000 modular units designed, and many of our modular projects under construction, let’s look at modular construction when compared to traditional site-build through a sustainable lens.

For years, the traditional practice of on-site wood framing has been seen as a reliable and low-cost construction method for housing. However, the need for sustainable construction paired with the increase in technological innovation has challenged the industry with respect to their usage of our natural resources and CO2 emissions. Some studies have estimated the building sector is responsible for 36-39% of carbon dioxide emissions and causes somewhere between 40-50% of global waste production. As a response, industrialized housing has become a popular topic among those in the architecture, engineering, and construction industry.

Industrial housing is a factory approach to wood-framed construction, such as modular and panelized systems. In modular construction, the assembly of units takes place in a controlled environment and then is transported by truck to the job site for on-site installation or stacking (in multi-family buildings). In panelized construction, elements such as floor sections or walls are made in a factory and then set in place on-site.

The Factory Process Cuts Down on Waste from the Construction Process.

Studies show that in new construction, especially in the multi-family building industry, the material waste produced and found in landfills is significant. According to CalRecycle’s 2014 Disposal Facility-Based Characterization of Solid Waste in California, construction and demolition materials were estimated to account for 21.7-25.5% of California’s waste disposal. This cause of excessive waste lies in the nature of the building process. Whether there is overbuying material to avoid potential schedule loss or buying commercially available material instead of exact lengths and amounts needed for cost-saving measures, some estimate up to 9% of materials by weight delivered to a construction site end up as waste.

Luckily, while we are seeing larger waste recycling programs, little has been done to maximize material usage. Industrializing this process and building offsite is a way to minimize waste and better utilize materials. In a controlled environment, factories are in a continuous flow of production and material inventory is managed for the factory, not individual projects. With more research and development funding fueling these factories, we have seen increased building intelligence with 3D modeling, automation, and material innovation, vastly cutting down on the amount of waste, and allowing for better reuse and recycle for the little waste generated. Materials are precut at stations prior to assembly at others, and working from detailed shop drawings greatly reduces waste.  Waste reduction = carbon reduction.

But isn’t there more material in modular building?

A common counterargument to modular’s sustainability is the amount of additional material used in modules. Since each module has independent floors, walls, and ceilings, there are inherent redundancies. The redundant assemblies reduce the need for other materials common in site construction such as gypcrete floors and metal hat channels for ceilings and walls required for acoustic assemblies. Other than enhancing a building’s acoustical rating and energy performance, a modular building made of wood can sequester carbon.

Though our team is currently working with industry partners on finding ways to minimize redundancies, additional wood per module helps balance as an atmospheric carbon saver. Wood is one of the best ways to sequester carbon in building materials.

Off-site Construction reduces on-site construction.

One of the largest touted benefits of modular construction is the benefit of time savings. Depending on the size of the building, location of job-site in relation to the factory, and intricacies of design, a modular project can save 25-50% of the time typically spent on a site-built project. This is because two construction processes are happening concurrently (the site being prepared, and the modules being assembled) with the end product tied together when the site or podium is ready for stacking. When properly scheduled, the modules or panelized systems can be installed on-site immediately upon delivery.

We know time savings can be optimized due to how quickly modules can be stacked. Over four days, our four-story student housing building on 2711 Shattuck in Berkeley, CA was erected at a rate of one floor per day. Another project, The Mayfair in El Cerrito, CA, stacked 7-10 modules per day and reached its full height in ten days.

This reduction of on-site construction results in less operating of machinery, less job-site visits, less scope of onsite work, and less overall commuting of workers and stakeholders – which ultimately, all result in lower carbon output.

We continue to measure our modular projects and compare the results to if the project was site-built and look to ways on utilizing this delivery method not only for cost and time-saving purposes but from an ecological footprint as well.

While every day we need to be incorporating sustainability ideas and practices into our work, Earth Day is a reminder to reaffirm our commitment to conserve resources, increase building efficiencies, choose sustainable materials, and lower our carbon footprint. We also want to thank our colleagues, clients, and partners who have climate change at the forefront of their practice and continue the work for leading better, healthier, and more innovative solutions in our industry, for our planet.

For further information and findings from our experience with modular, you can read more on a study we did with WSP and EPA in 2018 here.

Sources:

https://www.modular.org/IMAGES/foundation/NorthRidgeCO2Report.pdf
https://www.nibs.org/files/pdfs/NIBS_OSCC_EPAmodular-construction_2015.pdf