Status of Building Code Allowances for Tall Mass Timber in the IBC

Current status tracking of jurisdictions that have adopted tall mass timber code provisions from 2021 and/or 2024 IBC, either in whole or with local amendments. Provides comprehensive list of states that have adopted the new construction types (IV-A, IV-B, IV-C) allowing mass timber buildings up to 18, 12, and 9 stories respectively. Documents significant changes between 2021 and 2024 IBC including allowance for exposure of mass timber ceilings and integral beams in Type IV-B construction (20% in 2021 vs 100% in 2024). Updated as of January 2025, covering adoption status across 29 states and noting that additional local jurisdictions may have adopted provisions in advance of statewide adoption.