Bio-Based Building Materials: Designing a Sustainable Future

The Carbon Problem with Conventional Construction

The built environment is responsible for approximately 40% of global energy use and 36% of greenhouse gas emissions, according to the International Energy Agency. Within this, "embodied carbon" — the emissions produced in manufacturing and installing building materials — represents a significant and growing share as operational carbon (from heating and cooling) falls with efficiency improvements. Steel, concrete, and aluminum are among the most carbon-intensive materials in common use: producing a tonne of Portland cement generates approximately 0.8 tonnes of CO₂; steel production accounts for roughly 7–9% of global CO₂ emissions. Rethinking the material palette of buildings — toward materials that store rather than emit carbon — is a transformative design opportunity.

Promising Bio-Based Materials

Mass timber — including cross-laminated timber (CLT), glulam, and nail-laminated timber — has emerged as the most commercially developed low-carbon structural material. Wood stores carbon absorbed from the atmosphere during tree growth. A well-designed mass timber building can have negative embodied carbon — it stores more carbon than was emitted in its production. Brock Commons Tallhouse at the University of British Columbia (18 stories, completed 2017) and the emerging class of "plyscrapers" worldwide demonstrate that mass timber can compete with steel and concrete in high-rise construction. Hempcrete — a composite of hemp hurds (the woody core of the hemp stem), lime binder, and water — is a carbon-negative insulating material with excellent thermal mass. Its carbon negativity comes from the rapid carbon sequestration of hemp during growth combined with the long-term storage in the cured wall. Mycelium composites — grown by feeding agricultural waste to fungal mycelium in molds, then heat-treating — create lightweight, strong, fully compostable insulation panels and packaging materials. Companies including Ecovative Design have commercialized this technology.

The Design Vision

A building designed with bio-based materials throughout — timber structure, hemp insulation, natural clay plasters, recycled aggregate concrete for foundations only — could achieve near-zero or negative embodied carbon while creating healthier, more beautiful interior environments. Combined with passive solar design, mechanical ventilation with heat recovery, and renewable energy, such buildings point toward a future where the built environment actively participates in carbon sequestration rather than being a primary source of emissions.