Council on Tall Buildings and Urban Habitat
 

CTBUH Seattle YPC & Katerra Presentation: Cross-Laminated Timber
August 30, 2017

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SEATTLE – On Wednesday, August 30, The Council on Tall Buildings and Urban Habitat's Seattle Young Professionals Committee (YPC) hosted a Cross-Laminated Timber (CLT) 101 presentation series at Katerra’s Seattle offices.

Bill Maibusch, Project Executive, Andersen Construction, led the meeting with an introduction to the CTBUH and update on the upcoming CTBUH International Conference in Australia later in the fall.

Following Maibusch was Hans-Erik Blomgren, Director of Testing and Characterization of Mass Timber, Katerra. Blomgren began by presenting the CLT basics, followed by an explanation that CLT has an expanding demand, yet is in limited supply in North America. Blomgren’s main projects have been testing CLT for vibration, acoustics, and seismic performance and working through the regulatory requirements. He said he had been traveling up and down the U.S. west coast to promote the concept with local jurisdictions, with the eventual goal of CLT being used on Katerra construction projects by the first quarter of 2018.

The audience listens to the presenation on cross laminated timber at Katerra's Seattle offices.

Jennifer Caldwell, Design Project Manager, Katerra, spoke next and provided an explanation of the CLT design aesthetic, emphasizing its warm feel and texture, as well as the general sustainability of the product. Some of the challenges behind working with the product were presented during a walkthrough of routing mechanical, electrical, plumbing, and fire protection through CLT paneling.

Cross laminated timber at the Katerra offices in Seattle.
Rene Fresquez, Project Architect, Katerra, next provided 3D perspectives of CLT as a unitized floor system. He showed how design sketch inspirations went from a sketch to being placed into the model as an option for clients to make their unit ceiling selections.
Cross laminated timber presented by Katerra representatives.
Alec Thomas, Integrated Project Manager, Katerra, followed Fresquez by providing case studies comparing three assemblies: CLT, truss joist + CLT and post-tensioned (PT) concrete decking. The Timber Joist assembly involves nine steps with six different subcontractors, while a CLT floor system involves two steps (gypcrete/sound mat and CLT), making use of two different subcontractors. Efficiencies gained from reducing the material and subcontractor labor were discussed. Thomas concluded with a schedule analysis of using CLT as a floor system, using two case studies; one a high-rise building and the other a podium building, both in the Canadian province of British Columbia. Both projects showed substantial schedule improvements by using CLT as the floor assembly.