Components and systems of mass timber and taller wood construction
Mass timber products are the building blocks that make taller wood construction possible. Products in the mass timber family include cross-laminated timber (CLT), dowel-laminated timber (DLT), glue-laminated timber (glulam), laminated strand lumber (LSL), laminated veneer lumber (LVL), parallel strand lumber (PSL), and nail-laminated timber (NLT). Mass timber and engineered wood products can be used in an array of applications and are the foundation of taller wood building systems.
Types of mass timber framing systems
There is an ever-evolving number of options and systems when it comes to mass timber. Using various combinations and sizes, mass timber products can serve as beams, columns, floors, roofs, and walls considering the directional strength of each wood product. In contrast to conventional concrete and steel systems that tend to follow standard templates, mass timber systems offer the potential for greater flexibility, albeit not without some challenges.
Types of mass timber framing systems include:
Post-and-beam mass timber systems are a popular choice and resemble the common approach used in historic heavy timber buildings of the past. It is a skeletal framework of decking, beams, and posts supported on a foundation. The upright wood members are referred to as posts and the horizontal wood members referred to as beams. The post and beams are connected using mechanical steel fasteners. This system of construction requires no load-bearing walls. Glulam frequently serves as posts and beams. Decking systems can be made of panelized mass timber products such as NLT, CLT, or others. The post-and-beam system works well for open plan designs such as offices and commercial buildings.
Mass timber floor and wall systems
In contrast to post-and-beam, designers can take advantage of mass timber panels’ two-way spanning capability. This can include mass timber panels constructed to form a honeycomb structure well-suited to handle both vertical and lateral loads. In these systems, mass timber panels—similar to reinforced concrete and steel—form both floor and wall, with the walls bearing the load of the structure. In some instances, mass timber may form the core of a building, in place of concrete.
Hybrid mass timber systems
Hybrid mass timber systems are a broad category that refers to any combination of wood, steel, concrete, and other possible materials and building systems. Capitalizing on the performance and strengths of each building material, hybrid systems offer lots of flexibility. This can include a nearly all-wood solution that combines light-frame wood construction with mass timber panels, where only the foundation is concrete, and the connectors are metal.