With the rise of biophilic design principles in today’s built environment and the well-documented benefits of nature’s impact on human health and well-being, it should be no surprise that healthcare designers are increasingly interested in mass timber.
This engineered wood product is known for its strength, durability, versatility, and sustainability, including its carbon-sequestering attributes, whereby plants and trees absorb carbon dioxide from the atmosphere, convert it into organic matter, and store it in their tissues and the soil.
Taken together, the characteristics of this renewable and reusable resource have sustainability-focused organizations paying attention to its ecological and economic benefits. Here, we’ll examine the rising interest in mass timber facility design and the benefits of incorporating the material in healthcare facility projects.
What’s driving adoption of mass timber
Mass timber’s benefits as a building material can shine in many contexts—availability, constructability, sustainability, aesthetic appeal, and more. With strength comparable to steel and concrete, the resilient structural material also satisfies the human need for biophilic connection. Process improvements for forest harvesting have also yielded economic advantages that help sustain small communities through the ability to harvest in a way that promotes forest health, helping rebuild and revitalize timber and wood product manufacturing industries.
Additionally, as a known entity and time-tested material, mass timber’s fire-resistance is an inherent quality: when timber turns to char, fire goes out (which is why it can be difficult to start a campfire with a log). According to the paper “Fire Design of Mass Timber Members,” published by WoodWorks – Wood Products Council’s senior technical directors Richard McLain and Scott Breneman, “the predictability of wood’s char rate has been well-established for decades and has long been recognized in building codes and standards.”
In the European healthcare market, built and operational hospitals that feature exposed mass timber and wood finishes take cues from a wellness-centric and hospitality-inspired design ethos where biophilic properties are appreciated. So, why aren’t there mass timber hospitals in the United States?
One barrier is the delayed adoption of codes that the Centers for Medicare & Medicaid Services (CMS) relies on. In the past, the National Fire Protection Association’s codes did not recognize mass timber as an acceptable building material. However, the 2024 code revisions, expected to be adopted in 2027, will recognize mass timber as an approved building material for healthcare facilities. This change would allow reimbursement by CMS for care delivered in hospitals built with mass timber.
Challenges and opportunities
Regulatory frameworks and building codes are evolving to accommodate mass timber construction, and navigating policies requires collaboration between designers, builders, and authorities. For design and project teams interested in exploring the possibility of mass timber in healthcare, challenges and opportunities to consider can include:
Precedented and proven construction techniques: Advancements in prefabrication and economies of scale have helped mass timber become more affordable, available, and accessible. Today, this higher value proposition can partially be attributed to the ability to prefabricate elements in quality-controlled shop environments while foundations are concurrently built on-site. Precision manufacturing of fabricated structural components yields faster erection and shorter construction times, which can lead to significant savings in colder climates where building is seasonal (compared to all-season building in warmer climates).
Other benefits are site specific. For example, in a seismic zone with poor soil conditions, a lighter mass timber building can be constructed with much smaller foundations, saving cost and duration of construction while reducing the embodied carbon associated with concrete.
Infection control and prevention: Timber’s porous nature understandably raises concerns about infection control, which is imperative in a healthcare environment. However, innovative treatments and finishes can enhance its resistance to pathogens, such as a penetrating protective undercoat for timbers, dimensional laminated lumber, and engineered wood components like cross-laminated timber that enhance dimensional stability and protect wood from ultraviolet degradation and moisture absorption.
Trees produce phytoncides and terpenes, which have natural antimicrobial properties. Some of these compounds remain effective even when wood is used in building components. Additionally, according to the study “The survival of multi-drug resistant bacteria on raw Douglas fir material,” published in Nature, “no bacterial survival was detected on Douglas fir after application of a hospital disinfection protocol,” indicating that “these different results show that wood may have a place in the future of healthcare construction.”
Ongoing research on infection control in timber buildings highlights the importance of surface treatments and regular maintenance.
Interconnection of environmental and human health: Hospitals historically consume fossil fuels and produce more greenhouse gas emissions than other types of buildings. Because healthcare facilities are first and foremost meant to care for people, enforcing the Hippocratic Oath to “do no harm,” it follows that the buildings where healthcare is delivered must strive for the same goal by adopting sustainable design principles that reduce emissions and mitigate environment-related health issues.
Biophilia and well-being: Biophilic design, which incorporates natural elements to enhance well-being, is another key driver for mass timber in healthcare. Wood’s natural aesthetic and positive impact on indoor air quality, through the release of beneficial volatile organic compounds (VOCs), contribute to a healing environment. As referenced earlier, the terpenes (which are the scent of cut wood) have a natural bio-chemical benefit connected to biophilia. Connecting with nature also has an inherent calming effect on the body and mind that promotes healing. That said, a healthcare facility would not smell like fresh-cut wood as surfaces need to be sealed for cleaning.
Acute-care hospital case study
North of Lake Ontario in Picton, Ontario, Canada, the Quinte Health Prince Edward County Memorial Hospital broke ground in late 2024 and is set to be the first acute-care hospital in North America with an unencapsulated all-mass-timber structure, meaning that the timber is exposed and will not be encased in gypsum or covered up by anything else.
Expected to open in 2027, the approximately 100,000-square-foot facility will house 23 inpatient beds.
The project team, including HDR (Kingston and Ottawa, Ontario, Canada) and the Quinte Health Prince Edward County Memorial Hospital, worked with the authorities having jurisdiction to move past old stigmas associated with wood construction in healthcare. The project design had to navigate approvals from multiple public agencies, with the design team focusing on de-risking each step of the process.
By developing a blocking and stacking configuration that both satisfied clinical functions and adhered to existing building codes, the facility was divided into two “buildings” through the use of a firewall to permit combustible construction within the current building code. This design approach ensured full compliance with regional building codes, eliminating the need for approved variances. Additionally, sealing all the mass timber ensured the material could withstand the cleaning requirements of clinical spaces.
By reconsidering mechanical and electrical service layouts from the traditional distribution locations, the distribution of these systems was shifted from the typical corridor locations to align over adjacent inpatient washrooms. These are wet areas that would not receive exposed mass timber structure and ceilings, freeing up other areas in the facility such as patient rooms, nurses’ stations, and corridors to have clean, uninterrupted exposed wood ceilings and structures.
Glazing was standardized with a zero-edge parapet solution that allows for the mass timber material to be seen from the exterior, revealing the true nature of the building as community members approach. Finally, mass timber elements are used to sculpt the vertical fins that define an entrance beacon that acts as a lantern within the landscape.
Reaping healing benefits of mass timber
From concept to design and construction to high-performance operation, the metamorphosis of mass timber buildings is actively underway. Healing environments stand to benefit substantially from news ways of designing with this ancient building material.
As the old sayings go, what’s old is new again, and time heals all wounds. Mass timber in healthcare is meeting this moment with substantial sustainability advantages, undeniable beauty, and increasing business and design sensibility that harnesses the healing power of nature.
Duncan Griffin is director of sustainability, health, at HDR (Seattle) and can be reached at [email protected]. Jason-Emery Groen is design director of HDR (Kingston, Ontario, Canada) and can be reached at [email protected].
