Moving Back to Timber
“Old growth houses” as imagined by Midjourney
The desire for material permanence has led to the decline of wood as a primary building material, especially in commercial construction. However things today are still being constructed for demolition, without permanence in mind despite the materials having more permanent effects on the environment. An emergent technology in the sphere of construction and architecture is mass timber. Yes, timber construction has been around since the dawn of time, however mass timber is somewhat new. It is engineered from premanufactured multilayered wood with the main point of this emergent technology is to make tall buildings out of a product that is more environmentally friendly than traditional building material when proper protocols are followed.
But what is it that makes mass timber so unique? Traditionally timber structures need to utilize old growth wood that’s high quality. With engineered wood products, younger trees, softwoods, and what is deemed as a lower quality lumber can be used especially in products like glulam (glued-laminated timber). This allows us to take a more sustainable approach to the logging industry since more timber can be utilized. Due to mass timber production being relatively new, there are still minimal regulations in place to ensure that all of the wood being used is legally harvested or sustainably sourced– despite that being the intention of mass timber.
Common practice, mostly in America, is stick frame build. Most homes and buildings use light wood because it’s easy to transport and quick to construct with. However, lightframe construction is notoriously flammable. Unfortunately this brings down the reputation of wood as a safe primary construction material– increasing the hesitancy of adopting mass timber. How mass timber is engineered and assembled makes it naturally fire resistant. Besides the safety aspect of fire resistance causing the decline of wood as a structural building material, society moved towards a desire for material permanence. Steel and concrete theoretically provide that, even though contemporary society views all buildings, regardless of material, as temporary. Mass timber products were engineered to be sustainable in nature. Because it is designed to be prefabricated, there is the ability for ease of assembly and disassembly so the products can be reused if necessary, unlike concrete. The modularity capability of mass timber construction leads to adaptable end of life scenarios.
“Mass timber construction” as imagined by Midjourney
Perhaps the most important sustainability factor in mass timber construction is that it reduces the embodied emissions of buildings. Embodied emissions the millions of tons of carbon emissions released during the lifecycle of building materials; including, extraction, manufacturing, transport, construction, and disposal. 80-99% less embodied emissions than traditional building materials. An important aspect to the energy efficiency of mass timber is that mass timber panels can be used structurally. Mass timber is so structural in nature because it is engineered to have similar strength and stiffness in both directions rather than one. The structural aspects of buildings are where the majority of the embodied emissions lie (since they’re typically made of steel and concrete). Since the architecture and construction industry contribute the majority of greenhouse gas emissions globally, perhaps it’s time to start taking amore serious look at mass timber construction and encouraging research, testing, and regulations around this emerging technology.
By, Kay Kriegel intern extraordinaire @ Assembly.