Mass timber as a frame material

What is mass timber?

Mass timber is a collective term for building elements made of continuous, composite timber — as opposed to stud-framed walls where timber is used as sparse load-bearing elements with insulation between. The term covers CLT (cross-laminated timber), glulam, and solid timber blocks.

The three most common types

• CLT — cross-laminated panels that carry load in two directions. Used as walls, floors and roofs. Standard for multi-storey timber buildings.
• Glulam — glue-laminated beams and columns. Optimal for long spans and post-and-beam systems — halls, bridges and offices with open floorplates.
• Solid timber blocks — stacked boards without glue, joined with timber dowels. Less common; mainly niche projects with specific environmental requirements.

Benefits

• Low self-weight — less foundation, possibility to build on top of existing structures.
• Fast erection — prefabricated elements installed in days, not weeks.
• Renewable raw material with carbon-storing properties.
• Good indoor climate — wood regulates moisture and gives pleasant acoustics.
• Quiet, vibration-free on site — works well in dense urban environments.

Limitations to plan for

• Impact sound — requires a thoughtful floor build-up in housing.
• Moisture sensitivity — material and erection sequence must be protected from prolonged precipitation.
• Fire engineering — requires specific sizing and documentation.
• Price — can be higher than concrete at lower storey counts, but balances out when erection time and climate requirements are included.

When is mass timber the right choice?

Mass timber suits well when build time, climate requirements, self-weight or a visible timber aesthetic are highly valued. For multi-family buildings of two to eight storeys it's a very competitive alternative today.