New Mass Timber Building Codes to Take Effect in Michigan in 2025

Those seeking to design and build mass timber buildings in Michigan will soon have more options with the recent adoption of the 2021 Michigan Building Code, scheduled to take effect on April 9, 2025.

A photo of the Michigan State University STEM Teaching & Learning Facility during construction. Three stories of mass timber columns and beams are exposed.
Michigan State University STEM Teaching & Learning Facility

Those seeking to design and build mass timber buildings in Michigan will soon have more options – including the ability to go up to 18 stories – with the recent adoption of the 2021 Michigan Building Code, scheduled to take effect on April 9, 2025.

Michigan is currently operating under the 2015 Building Code, the first version to allow for the use of cross-laminated timber (CLT) panels in commercial construction. The incoming 2021 Michigan Building Code (Rule Set #: 2022-57 LR; Title: Construction Code - Part 4. Building Code), based on the 2021 International Building Code, includes three new mass timber building types – Type IV-A, Type IV-B, and Type IV-C, allowing for mass timber structures up to 19, 12, and 9 stories, respectively. Type IV-HT (just Type IV in the 2015 code) pertains to heavy timber structures.[1]

A graphic of the three new mass timber building types in the recently adopted 2021 Michigan Building Code, which takes effect on April 9, 2025. The incoming 2021 Michigan Building Code based on the 2021 International Building Code, includes three new mass timber building types – Type IV-A, Type IV-B, and Type IV-C, allowing for mass timber structures up to 19, 12, and 9 stories, respectively. Type IV-HT (just Type IV in the 2015 code) pertains to heavy timber structures.
Source: American Wood Council

The 2021 Michigan Building Code was filed on December 10, 2025 and can be viewed on the website of the Michigan Department of Licensing and Regulatory Affairs - Bureau of Construction Codes.

MassTimber@MSU will collaborate with partners including the American Wood Council (AWC) and WoodWorks to help prepare the Michigan real estate, architecture, engineering, and construction industry to work with these new mass timber codes. Our first scheduled training, led by Ed Lisinski of AWC, will take place on March 19 at 10:00 a.m. as part of the first-quarter Michigan Mass Timber Community of Practice meeting. To participate in the Michigan Mass Timber Community of Practice, please complete this form.

The adoption of the 2021 Michigan Building Code opens the door for new mass timber opportunities in Michigan. Please contact Sandra Lupien at lupiensa@msu.edu to let us know how MassTimber@MSU can support you as you work with these new codes on your mass timber projects.

 

[1] “Heavy Timber” refers to construction materials (posts and beams) sawn from a single log, whereas “Mass Timber” refers to a variety of engineered wood construction materials – posts, beams, and panels – made from dimensional lumber or veneers laminated together using adhesives, dowels, or nails.

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