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Innovation in the Building Industry - ICC Tall Wood Buildings Ad Hoc Committee Update

Thursday, May 24, 2018  

With national and international interest in the design and construction of tall wood buildings, the ICC Board of Directors solicited feedback from the ICC Membership on the creation of an Ad Hoc committee for tall wood construction. This ultimately led to the Board’s establishment of the Ad Hoc Committee on Tall Wood Buildings (TWB) in December 2015. The Board charged the Committee with exploring the building science of tall wood buildings and to investigate the feasibility of and take action on developing code changes for tall wood buildings. To accomplish the work, the Board appointed members to the committee who represent a cross section of stakeholder interests, including code officials, fire protection engineers, structural engineers, architects, fire service personnel, and representatives of the construction materials industries. After reviewing various nominations from SEAOCC, SEAONC, SEAOSC and SEAOSD, Matt Timmers, SE of John A. Martin & Associates of SEAOSC (pictured above) was submitted as candidate to represent SEAOC for the TWB committee, due to his research of utilizing cross-laminated timber in tall wood construction, and he was subsequently approved.

In the execution of the scope of work, the committee has been reviewing available information relative to the design, construction, occupancy and use of tall wood buildings. The investigation is focused solely on mass timber wood products and the need for the requisite technical justification to support the code development process. The Committee has excluded from discussion any light frame wood construction and has preserved the requirements for Heavy Timber construction in their present form in the I-Codes.

After half a dozen in-person meetings, presentations from industry experts, full scale fire tests, and countless working group calls, the committee submitted a major set of proposals into the Group “A” change proposals of the IBC 2021 development process. The Group “A” includes code changes to the IBC non-structural provisions. TWB Ad Hoc Committee proposals included three new construction types, Type IV-A, IV-B and IV-C constructed of mass timber or non-combustible materials. These new types are based on the existing Heavy Timber construction type (renamed Type IV-HT) but with additional fire resistance ratings and levels of required non-combustible protection. The proposals have provisions for up to 18 stories of Type IV-A construction for Business and Residential Occupancies.

The fourteen code changes were introduced at the Committee Action Hearings in mid-April. As approved at the hearings, certain occupancies have an allowable height of 18 stories, which exceeds the current limitation of six stories. Many of the code changes provide additional details to ensure both the structural and fire resistance integrity of taller mass timber buildings. All 14 code changes were approved to be advanced to the Public Comment Hearing which will occur in October of this year. A second set of Group “B” proposals to the IBC structural provisions, including structural special inspection and material specifics, are under development for submittal in January of 2019.

The Ad Hoc Committee on Tall Wood Buildings continues to collect and review data, including analysis of the results of ongoing full-scale fire testing and an evolving supply of new timber technology, in the development of draft code proposals. Please to visit the website at to follow and monitor further Committee progress. For additional information, please contact Matt Timmers at