Perspectives 10.27.2020

Why Not Wood?

Our firm is committed to mitigating the environmental impacts of our projects, processes, and construction. We recognize that heavy timber has the potential to radically realign a building’s relationship with embodied carbon. From the first stages of design to the recyclability of a structure at the end of its life, mass timber is a sustainable option at its core: It’s a renewable material that also offers stunning aesthetics.

Here are some expert insights from scientists and designers on why choosing wood for a building, no matter the context, is a responsible and future-ready choice.

Detail of our SoLo house, in British Columbia

What is mass timber?

Mass timber is different from the light wood frames of suburban homes or strip malls. Rather, it’s resilient, long-lasting, and sustainable, made from many different types of fast-growing hardwoods that are adjoined with adhesives and fasteners, mass timber is exponentially stronger than standard timber. With the production of architectural steel accounting for 5% of greenhouse gas emissions worldwide, mass timber is a clean, green, renewable alternative.

Detail of the interior of Framehouse, by our Copenhagen Perkins&Will/SHL studio

Mass timber can be used in a variety of ways, from classic post-and-beam construction to experimental applications such as pre-fabrication and 3D printed structures. While the latter are currently not widely used, early material prototypes are more and more accessible, and could be widely available in the near future.

You may hear many three-letter acronyms for mass timber products, and there are many to choose from. Today, some of the most popular products on the market are Glulam, CLT (cross-laminated timber), and more recently, DLT, (dowel laminated timber) a 100% wood-based product that uses wooden joinery rather than glues or fasteners, meeting even the most ambitious ecological standards. When evaluated on a project-by-project basis, it’s clear that the variety of options available align with a variety of sustainability standards and budgets, allowing for holistic customization of a project.

A richly (en)grained history

Wood has been a principal building material since the earliest eras of human history. Even today we have excellent examples of wood-framed construction that have lasted for several centuries. Dr. Werner A. Kurz, lead developer and researcher for the National Forest Carbon Accounting System for Canada, cites a 600-year-old wooden home and retail outlet in Switzerland. The house is in excellent condition, as the building has been continuously occupied, cared for, and maintained for a variety of purposes. The building is also an example of timber’s resilience, a key factor in Dr. Kurz’s work on constructing for carbon sequestering over time. When a material is proven to be this strong, resilient, and sustainable, it begs the question: Why not build our cities with wood?

During Western industrialization, factories and warehouses were often built with heavy timber technology due to the method’s advanced fireproofing qualities. Wood’s natural ability to char rather than burn protected warehouses and factories full of valuable goods from the frequent fires of the 19th and early 20th centuries, many of which were caused by candles, gas lamps, and furnaces. Charring refers to the wood beam’s capacity to only burn at the outer edges at a very slow rate, protecting the structural integrity of the inner core of the beam, thereby keeping the building structurally sound. This method is still used in modern construction today, along with additional layering of other wood products around the core of the beam. By “overengineering” the thickness of columns, it slows the charring process even further. This natural quality of mass timber makes it a viable option for even the most stringent safety measures in our modern cities.

Detail of the timber ceiling construction at Aaniin Community Center and Library in Ontario
Detail of the timber ceiling construction at Aaniin Community Center and Library in Ontario
Nordic Structure’s forestry division manages nearly 4 million acres of black spruce.

Sustainable to the core

Hardwood forests are one of the world’s most powerful tools in the battle against CO2 emissions. The vast forests of the northern hemisphere, as well as tropical rainforests along the equator naturally and efficiently absorb greenhouse gases. They also have the ability to regenerate at a more rapid pace than fossil fuels and other processed building materials. However, a perennial concern for many people is the question of wood scarcity. This is addressed by Dr. Kurz: “Even if all of Canada’s commercial foresting were geared toward architecture in cities, we would still have thousands of acres of forest left,” he says. And that supply could be bolstered by looking to sustainable forest management techniques, as well as time-honored traditions exercised in countries like Scandinavia and the Netherlands.

For example, with effective and smart forest management, we can harvest the timber products we need to build our cities in ways that not only benefit the urban landscape, but the forestry sector as well. Young forests, the types that produce the timber for mass-market construction materials, are even better at absorbing CO2 from the atmosphere, and by cultivating them for commercial use, we can save the old-growth forests from exploitation. “By looking to sustainable forest management, we can offer the high-quality wood products the market needs,” says Dr. Kurz, who also sees this effort as going hand-in-hand with reducing fossil fuel emissions worldwide.

Processing and transporting the wood for mass timber products from Nordic forests
Rendering of the timber structure of our DC Southwest Library

Rapid speeds

One of the most appealing aspects of mass timber as a building material is the relative ease and rapid pace of construction it allows. Mass timber elements are often highly customizable, ready to be unpacked and lifted into place. “The materials, assembled as a kit-of-parts offsite, make construction feel like we’re building with Lincoln Logs,” says senior associate Joshua Rubin. This quality of timber construction also adds to a uniquely rapid delivery timeline, which is a huge plus for designers and clients alike. “In just a matter of weeks, we can see the rapid results of timber framing,” Matt Covall, a designer in our San Francisco studio. “Shortened timelines are already cost saving, and on top of that, expensive finishes are not always necessary, since wood is beautiful when expressed in its natural form.”

Speed is also achieved, in part, through the relative light weight of mass timber compared to steel and cement. This is an inherent benefit, and one that cannot be overstated: No engineering is required to lighten the material. Speed played an important role in planning for a confidential timber project in the northernmost reaches of Canada. With an exceptionally short season for construction, our design for a remote worker’s camp—a temporary building typology that offers living units for oil and gas workers in remote tundra regions—took advantage of mass timber’s flexibility. We developed a kit-of-parts and assembled all the wood pieces offsite to be delivered and then quickly assembled in just a matter of weeks, without sacrificing comfort or style. Worker’s camps of this sort are often uncomfortable, raw spaces laid out like shipping containers with minimal regard for the well-being of the inhabitants. With the warmth and high-quality character of timber, however, our team was able to offer an inviting home with built-in amenities and a central layout for socializing. The project also allowed us to push the sustainability envelope for our client: The timber parts can be easily taken apart, stored, or transported to a new site as necessary. The ability to easily assemble and dismantle mass timber environments promises a regenerative, rather than disposable, lifecycle for building materials. The Canadian worker’s camp was an exciting way to reimagine the status quo and use the inherent qualities of mass timber to elevate the experience of each worker.

Expressive character

Our design of 1 De Haro, a building in one of San Francisco’s historically industrial quarters, expresses the original character of the area through wooden materials. “We approached the project’s sustainability goals head on with the client from the very beginning, and heavy timber was a natural choice,” says designer Matt Covall. The structure went a long way in achieving ambitious sustainability and LEED-oriented goals, while also elevating the design of the De Haro tenant spaces. Building for two distinct clients—tech startups looking for Class A office space above, as well as light industrial outfits on the ground floors—initially posed an aesthetic challenge, but the mass timber design met the needs of both. The wood offers a raw, decorative element at street level, consistent with the neighborhood history, but it also worked, with slight variations in interior décor, for the modern offices above. This building represents the variety of mass timber’s visual potential, as well as its inherent adaptability towards client customization.

A short film on the 1 De Haro project, directed by our San Francisco studio

The creative expression of mass timber was also explored in our D.C. Southwest Public Library, an iconic park-side public amenity for an emerging community. “This was a project for and by the community, a neighborhood proud of their history and eager to boldly express their story,” said designer Joshua Rubin. Timber pieces were brought to site ready to be quickly and easily assembled, and easily lifted into place by cranes, cutting construction time significantly. The material was also an ideal form for uplifting southwest D.C.’s mid-century modern character. Glulam beams form bold “V” shapes and a “front porch” protecting a modern glass curtain wall beneath. The result is a well-loved design that complements its surroundings, while also meeting or exceeding sustainability goals and bringing people, books, and support networks together under one roof.

While there is still so much more to research, experiment with, and learn, mass timber has already proven its benefits. Both resilient and beautiful, wood structural products are entering the market at a rapid pace, promising more competitive pricing, technical refinement, and increased demand in the very near future. We’re excited to be pioneers in this material renaissance, sharing our knowledge and insight with the industry, and pushing architecture and design to go greener.

For more information about timber and some of our other innovative building technologies, check out our Building Technology Lab website.