Performance of a CLT Modular Building Utilizing Low-Value Pine Lumber from Logs Harvested in Pacific NW Forest Restoration Programs

Research Team:

Mariapaola Riggio

Lech Muszynski

Project Duration:



A.A. “Red” Emmerson Advanced Wood Products Laboratory (OSU)


The objective of thisproject is todesign, build, deploy, instrument, monitor and publicize a demonstration modular unit made from cross-laminated timber (CLT) using low-grade Ponderosa pine (PP). The demonstration unit will highlightthe viability of large-volume production of modular units that can be used in low-and mid-rise structures.


Restoration programs in Pacific NW generate a large volume of underutilizedPP logs. If a substantial volume of these logs can be used in high-value product, such as CLT, the revenuemight to some degreeoffset high costs associated with the restoration operations. This research builds up on 2017 Wood Innovation project led by Dr. Muszynski and Dr. Riggio aimed at defining a custom lay-up of CLT from low-value PPthat meets the standards (as defined by ANSI/APA PRG 320). This research is aimed at building a major demonstration project so that the public perception towards low-value PP logs could be changed.

Research Details

Research approach overview (project outline), critical bits of info, e.g. products tested, species, assembly materials, etc. The project has two major activities:

1. Modular Unit Design: Modular units with a focus on easy assembly and disassembly to be designed using low-grade PPCLT.The structure is designed using an innovative connection that is easy and quick to assemble and disassemble.

2. Modular Unit Demo: The designed unit will be demonstrated in two phases: a single module demo and a full-scale model serving as a “living lab”. Moisture content and moisture-induced movement of the panels will be monitored during this phase.

Results and Resources

Designs of modules assembled with innovative connectors are developed based on 8 foot (2.4 meters) and 12 foot (3.6 meters) wide panels. Based on preliminary numerical results, CLT made from low-grade Ponderosa pine has been found to be adequate for low-rise applications. These results will be presented at the Mass Timber Conference 2020, Forest Product Society International Conference 2020, and World Conference on Timber Engineering 2020.