Samples

CLT is a type of mass timber element most commonly used as a horizontal floor system, with a visible ceiling surface that spans between beams.  CLT floor systems can be carried by glulam beams (GLB), steel, bearing walls or other structural systems. The softwood structural lamella (individual lamination layers) are laid up in alternating layers, with an odd number of plies such as the 3-ply shown here. The cross-lamination adds bi-directional span capabilities and dimensional stability that are unique in the mass timber product families, and also requires a certification-based approach to manufacturing (see more info below).

The engineering properties of this element are based on certifications that verify the manufacturing process, final product, and ongoing quality assurance program.  In North America, structural CLT products are certified to the requirements of  the ANSI/APA PRG 320. Standard.  A manufacturer typically tests and certifies their own proprietary layups to create a product family. The lamination in the longer span direction are finger-jointed and selected face layers are selected for visual/architectural qualities.  In the case of Kalesnikoff CLT, the individual lamella are also edge-glued.

Because not all of the fiber is oriented the same direction, and not all manufacturers use the same fiber or combination of layers, deciding on the right CLT sizing is specific to the manufacturer, the governing span between beams, and other engineering criteria like vibration or fire resistance.  Wall elements and vertical shafts can also be constructed of CLT, and industrial grades are available, but are not included in this e-sample package.

The large manufactured size of North American CLT panels creates advantages in installation, engineering of floor diaphragms, and architectural expression.  Each manufacturer’s press has been designed for specific maximum sizes. Once you have a basis of design and engineering with their species, working to optimize building grids, installation times, and material utilization can make the difference in cost competitiveness of mass timber.

Ask info@offsitewood.org if you have early-phase design questions about cross-laminated mass timber floor systems, or contact the manufacturer’s sites and technical sales team for more info.

DLT is a type of mass timber element most commonly used for visible ceilings and roof assemblies, usually spanning between beams. In these horizontal slab configurations, the softwood structural lamella (individual lamination layers) are laid side by side and specialized hardwood dowels are pressed through precision-drilled holes to create a large billet or structural plank. Wall elements are also used especially in Alpine Europe but are not shown in this e-sample.

The engineering properties of this element are based on standards, much like a solid wood joist of a certain species can be calculated with a span chart (except that framed floors have joists at 16 or 24” on center while DLT floors have the span elements directly next to each other).  Very slim floor profiles are possible because all of the fiber is oriented in a structural direction, but the system is best suited for simple spans and does not have the bi-directional strength qualities of CLT.

The smaller unit size of the billets and limited strength as a diaphragm can be overcome in shop-fabricated elements that create larger floor or roof panels by combining billets under a sheathing layer that provides structural shear capacity and weather protection during installation.  An architectural advantage is that the exposed ceiling face can be milled before lamination, to create acoustic or aesthetic profiles.

Ask info@offsitewood.org if you have early-phase design questions about DLT or other mechanically laminated mass timber systems, or contact the manufacturer’s sites and technical sales team for more info. .

GLB is also known as architectural glulam. This is a mass timber element with laminations in a single direction to form beams, columns, or rafters with capabilities for long spans, curved layups, and custom connectors.  In a full mass timber building, glulam beams form the core structure for the horizontal slab elements of CLT, DLT, or GLT spanning between beams. 

In the most common North American layup, the softwood structural lamella (individual lamination layers) are stacked vertically and glued with horizontal joints, as shown by the Art Massif and Kalesnikoff e-samples.

The small-block glulam product line represented by Nordic Structures has its own unique structural properties and certification. It was developed to utilize the tip logs of small diameter boreal spruce fiber in a monolithic layup.

The engineering properties of GLB elements are specific to the species, grade, and product that is manufactured and identified in accordance with ANSI A190.1 (US) and/or CSA O122 (Canada).  Both North American standards establish requirements for the production and quality control of structural glulam.

There are also artisan lines represented in this e-sample section by edge-matched and grain-matched GLB options. These rely on the engineering properties of a core beam or source beam. This category carries company-specific specialties and grading designations, such as the Fraserwood e-samples of edge match and grain match glulam.  Art Massif makes an edge-glued surface layer onto a spruce core beam in their Prestige line which will be added soon. 

Grain match glulam involves a source beam that is resawn, dried, and glued back together,  In that case the source beam provides the engineering limits,  plus advantages of dry conditions to the heart of the beam that improve the strength of connections and quality of interior finishes.

Small-block glulam is a technique pioneered by Nordic Structures in North America, which has unique capabilities and benefits.  Utilization of small sections allow for the tip logs from small boreal spruce trees to be turned into large elements and a flexible cross-section libraries for  custom profiles. 

Each of the GLB e-samples represent a successful regional adaptation by fabricators who have transformed their local material into an engineered product and system.   Ask info@offsitewood.org if you have early-phase design questions about architectural glulam beam systems, or contact the manufacturer’s sites and technical sales team for more info.

GLT is also known as glulam decking and is a type of mass timber element most commonly used for visible ceilings and roof elements, usually spanning between beams. Similar to a glulam beam but oriented in a horizontal floor/ceiling system, the softwood structural lamella (individual lamination layers) are laid side by side and glued with vertical joints to create a large billet or structural plank.

The engineering properties of this element are specific to the species, grade, and product that is manufactured and identified in accordance with ANSI A190.1 (US) and/or CSA O122 (Canada).  Both establish requirements for the production and quality control of structural glulam.

Slim floor profiles are possible with GLT decking because all of the fiber is oriented in a structural direction, but the system is best suited for simple spans and does not have the bi-directional strength qualities of CLT.
The smaller unit size of the decking elements and limited strength as a diaphragm can be overcome in shop-fabricated elements that create larger floor or roof panels under a sheathing layer that provides structural shear capacity and weather protection during installation.

Ask info@offsitewood.org if you have early-phase design questions about mass timber decking systems.