What is mass timber?

• A. Concrete and steel framing.
• B. Plastic polymer framing.
• C. Structural timber products like cross-laminated timber used for sustainability and carbon storage.
• D. Traditional softwood lumber without engineered components.

Answer: (C)

Mass timber refers to engineered structural wood products designed to carry building loads, created by bonding or laminating wood into large, strong components. A centerpiece of mass timber is cross-laminated timber, made by stacking wood layers at right angles and gluing them together to form panels that are strong in both directions. This panel approach enables fast, efficient construction of floors and walls for multi-story buildings.

A key benefit is sustainability through carbon storage. The wood used in mass timber stores carbon that was absorbed during the trees’ growth, and the manufacturing process generally uses less energy than making steel or concrete. That stored carbon remains locked in the building components for their life, contributing to lower embodied carbon.

So mass timber is about these engineered wood products used in structural applications to achieve sustainable, carbon-storing buildings. Concrete and steel framing aren’t timber-based, plastic polymer framing isn’t timber, and traditional softwood lumber without engineered bonding doesn’t provide the same panelized, high-strength, multi-directional performance that defines mass timber.