Built environment & materials
Mass Timber
Structural building products made by bonding layers of solid wood — such as cross-laminated timber — enabling multi-storey wood buildings with far lower embodied carbon than steel or concrete.
Definition
Mass timber is a family of large-format engineered wood products — including cross-laminated timber (CLT), glue-laminated timber (glulam), nail-laminated and dowel-laminated timber, and structural composite lumber — made by fastening or bonding layers of dimension lumber into panels, beams and columns strong enough for mid- and high-rise construction. CLT was first developed in Germany and Austria in the early 1990s and entered the US International Building Code in 2015, with later editions permitting buildings up to 18 storeys.
References
product types, CLT structure, 2015 IBC recognition, 18-storey provisions
CLT 1990s origins, structural applications, weight advantages
Overview
What it means
Wood stores biogenic carbon and typically has much lower embodied emissions than concrete and steel; mass timber is prefabricated, lighter (reducing foundations) and faster to erect. Sustainability hinges on responsible forest sourcing and end-of-life planning.
How it is used
Used in offices, schools, housing and hybrid timber-concrete structures; building codes, fire engineering and insurance frameworks are adapting as the market grows.
Why it matters
Construction materials account for a large share of global emissions; mass timber is the most credible structural pathway to low-carbon buildings at scale.
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