Mass timber has proven to be an effective building system that reduces construction costs, speeds construction time, and creates better living and working spaces. Another less-explored advantage is mass timber’s ability to be deconstructed and reassembled in different configurations through a process called Design for Disassembly and Adaptability (DfDA). DfDA allows a mass timber structure to become a true kit of parts when its useful life comes to an end.
Transforming Structures Through Reuse of Mass Timber
DfDA is a process for taking apart the pieces of a building and reusing them with little modification. It involves developing a system of components and attachment processes that can be used multiple times without downcycling the material. Beams, columns, and slabs can be screwed and bolted together and to connections, taken apart and reused or re-configured without degradation to the mass timber elements or even the connectors.
No other system can match mass timber’s ability to be disassembled and reused in the construction of entire buildings. Specifically, mass timber systems show the most potential for transforming wide-floor-plate office buildings into light-filled residences. It would be incredibly easy to cut a hole in the roof, un-bolt/un-screw the roof slab and lower the floor slabs to create a light shaft in the middle of a building. Using an acoustic mat between a concrete topping slab and a mass timber slab also allows for easy removal of the concrete slab.
Or, when dealing with long rectangular buildings, the bays can be removed throughout to create slices that bring in more light and connection to the world outside. The removed pieces can then be easily designed into a new building elsewhere.
Although mass timber is a new construction system and codes for its use are still evolving, the upcoming International Building Code now allows for full exposure of ceiling slabs in situations where slabs were previously only allowed to be partially uncovered. Additional testing will continue to show how mass timber can be left more exposed.
Achieving Resilience and Sustainability with Mass Timber
An advantage of mass timber systems is that they can be used to make buildings more resilient to seismic and wildfire impacts. With their density and interconnection, mass timber systems give structures a greater ability to withstand destructive forces, allowing for faster re-occupation after a seismic event. In wildfire scenarios, the char created actually enhances the wood, making it more resistant to heat and natural decay.
Combining DfDA with mass timber systems also provides several environmental benefits. Along with being the largest emitter of greenhouse gases, the construction sector sends about 150 million tons of construction debris to landfills every year in the United States alone. Reusing mass timber building materials would help keep embodied carbon in the structure and significantly reduce waste.
Exploring Mass Timber’s Full Potential
Reused mass timber elements are the perfect construction material for a circular economy. The challenges to reusing mass timber in a DfDA scenario are meeting life safety and code compliance while continuing to develop systems that more easily allow for DfDA.
However, these are not unreachable requisites. Time and testing are needed to ensure that glues remain strong over periods of use and connections are not undermined by removing connectors and reusing screw and bolt holes. Structural guidelines for reuse would benefit DfDA development, however, the current market interest in modular building may be what pushes mass timber to reach its full potential as a reusable building material.
Learn more about how Jensen Hughes supports mass timber projects.
