What We Have Learned About Mass Timber

Mass timber construction uses multiple layers of wood mechanically combined to create a sturdy and robust building panel. The individual wood layers can be merged using nails, dowels, or glue. 

It may seem like an up-and-coming construction innovation, but the building material has been used in Europe since the 1990s. The material is starting to gain some traction in the United States, with numerous mass timber projects in development across the country. 

GBA recently partnered with AIA Pittsburgh and Rothoblaas, a building company specializing in developing products for mass timber construction, to host an informational session about the basics of building with mass timber. Rothoblaas Midwest Area Sales Manager Bill Broderick and Technical Product Representative Chad Mosesso provided an overview of mass timber construction and answered questions from attendees. Here are some of our main takeaways:

Mass timber has plenty of sustainability benefits.  

Unlike concrete or steel, whose production contributes to 8% of greenhouse gas emissions globally, adopting more mass timber structures has the potential to reduce these emissions by at least 14%.  

As a renewable resource, greater use of mass timber can also aid forest management systems. An increased demand for harvesting soft wood–like pine or fir–would create more space in US forests, which are currently overcrowded and leave trees competing for necessary resources. According to Jonathan Geyer at the PA Department of Agriculture, increased demand for wood products has the capability to also increase sustainable forest management, which would in turn improve forest health. This demand could also strengthen rural economies, with the potential to involve localized small-scale lumber providers in the wider construction markets. 

Building with mass timber has positive implications for the way humans experience the built structures. Constructing with exposed wood may also promote a sense of environmental connectedness and biophilia, an innate human desire to connect with the natural environment.  

Carbon12, a new residential development in Portland, OR, is currently the tallest mass timber structure in the United States. Photo via Carbon12

Mass timber can increase construction efficiency. 

Mass timber has plenty of opportunities for customization, reducing the need for renovations down the line. Structures also come pre-fabricated, which leaves most of the on-site construction process dedicated to assembly. This reduces construction waste, and any waste that is generated can often be repurposed. Crews can also be smaller—up to one-third the size of a traditional project. This overall approach could greatly benefit urban infill sites. 

Mass timber can be more cost-effective in the long run. 

While certain mass timber projects may have more upfront costs than building with concrete or steel, associated costs related to construction and maintenance could be vastly cheaper. Mass timber also claims to be fire, water, and earthquake-resistant, which could add to building durability and adaptability.

 

Brock Commons, a student housing site in Vancouver Canada, is LEED Gold-certified. Photo via ArchDailyOverall, mass timber can be a worthwhile building material to consider implementing in any project and there’s great potential for building professionals to become more knowledgeable in forest management. “If architects and engineers want to be confident that claims regarding the sustainable attributes of mass timber are valid, they should become more knowledgeable about how forests actually work―ecologically and as a harvested natural resource,” says Dario Giandomenico, GBA’s Vice President of Strategy & Innovation.

 

Additional Background on Pennsylvania’s Forests

Jonathan Geyer from the Department of Agriculture also offers this detail on our region’s forests: The Commonwealth’s forests are different from forests in the south and the west, as our forests are predominantly hardwoods. Hardwoods are trees that have leaves, while softwoods are trees that have needles. Pennsylvania’s forests are roughly 90% Hardwoods and because of this Pennsylvania is a national leader in the volume of hardwood growing stock, production of hardwood lumber, and export of hardwood lumber. While one builds their home with softwood lumber, it is furnished with hardwood floors, cabinets, and furniture. Most mass timber is currently made of softwood, however universities like West Virginia University and Virginia Tech are exploring building code compliance of using hardwoods in mass timber.  When greater adoption of Hardwood mass timber occurs, Pennsylvania is poised to become the leading hardwood mass timber producer as we have the raw material and a vibrant forest products industry.

Additional Resources 

 

The information in this blog is not a full assessment or endorsement by GBA nor is it a comparison of attributes among different construction materials. The claims made in the presentation referenced here are those of Rothoblaast and the wood products industry.

GBA and AIA Pittsburgh plan to explore this topic more deeply in 2022 so keep an eye on our calendars for more on this building method!

 

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