Material Salvage Research Initiative  Co-Principal Investigator Research Update

Dr. George Berghorn 
Associate Professor, Construction Management Program 
MSU School of Planning, Design and Construction

An exciting part of the Michigan Salvage and Reuse Initiative that was funded by a Michigan Department of Environment, Great Lakes, and Energy Market Development Grant in 2019 is research and development activity focused on assessing the suitability of salvaged lumber for use in mass timber products.

Mass timber is a modern engineered layup of resin and lumber to make large cross-section beams and columns, floor plates, and structural wall panels. While mass timber construction is a newer idea, especially in the U.S., these products bear some similarity to the performance and assembly of timber frame construction which has been used for hundreds of years in Asia, Europe, and North America.Of the variety of available mass timber products, glue laminated timber (glulam) and cross laminated timber (CLT) are found most commonly in new construction. These products obtain their strength from alternating layups of lumber and the resins that are used to bond the layers.

Part of our research team is also part of the domicology research group, housed at the MSU CCED. Through that work, we completed a preliminary assessment of structurally usable lumber available in abandoned buildings in Michigan. What we found was staggering. The roughly 226,000 abandoned homes in Michigan could yield over 1.2 billion board feet of structurally usable lumber. Further analysis revealed that finding various recycling and reuse schemes for this wood could save about 6.3 metric tons of carbon dioxide equivalent per house. Our team looked around and decided that evaluating the potential for using salvaged wood in mass timber was a critical issue for Michigan and the U.S.

Since our restart in August ‘20 (COVID-19 had us shut down since March), our lab has processed over 2,000 board feet of salvaged lumber. We have evaluated materials from two homes, one built in 1902 and the other built in about 1954, both deconstructed in 2016. We are planning to receive more material this fall and winter from southeastern Michigan residential deconstruction projects. The team is evaluating the material for its structural and physical properties, and we are finding that the vast majority of the wood meets the minimum requirements to be used for manufacturing glulam and CLT.

Next up is for the team to work on creating glulam and CLT layups using the salvaged lumber along with controlled proportions of graded virgin material. We will then subject those products to mechanical and physical testing to determine their suitability for use. The work will also spawn an environmental and economic impact study, examining the impacts if this work were to be brought to commercial scale. We hope that this work will significantly impact the wood products and construction industries and improve the environmental performance of what is roundly viewed and treated as garbage—deconstruction lumber.

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