Tennessee State Building Code — 2021 I-Codes via State Fire Marshal SBCO (TN)

Tracked preemption from the Tennessee overlay bundle.

Overview

Effective
2025-04-17
Sunset
Authority
state
Scope
state:TN

Trigger predicate

When this evaluates true for a parcel, the law's preempted fields take precedence over base zoning.

always true

Preempted fields

4 fields on the base district schema are rewritten when the trigger fires.

FieldOpValueNote
building_code.adopted_editionoverrideI-Codes 2021 (IBC, IFC, IRC, IMC, IPC, IFGC, IECC, IEBC, IPMC)Statewide minimum effective 2025-04-17; transition window for previously-submitted plans through 2025-08-15
building_code.enforcement_authorityoverridestate_fire_marshal_codes_enforcement_section_defaultSBCO Codes Enforcement Section enforces in non-opted-in jurisdictions; localities may certify their own code enforcement to the State Fire Marshal
residential_code.local_opt_out_eligibilityaddtwo_thirds_governing_body_vote_to_exempt_1_2_familyTCA §68-120-101(a)(8): a municipality may exempt one- and two-family dwellings from statewide standards by 2/3 affirmative vote of its governing body
residential_code.county_default_exemptionaddcounties_may_decline_to_adopt_residential_code1-2 family residential code adoption is opt-in for counties; many TN counties have no residential code, leaving SFD/duplex construction unregulated outside municipal limits

Citation

Authority source
Tenn. Code Ann. §§68-120-101 through 68-120-123 (Statewide Building Construction Safety Standards); Tenn. Comp. R. & Regs. Ch. 0780-02-23 (State Building Code rules); 2025 SBCO codes adoption notice
§ §68-120-101 et seq.
https://www.tn.gov/commerce/fire/codes-enforcement/history.html

Research notes

TN is one of the few states where 1-2 family residential code adoption is genuinely optional at the county level — material to underwriting rural SFD/build-to-rent sites. Commercial code is mandatory statewide. Energy code: TN amended IECC 2021 with state-specific modifications (no ERI path requirement for residential). Federal conflict check: HUD 24 CFR Part 3280 preempts state/local construction standards for HUD-code manufactured homes (see TN_13_24_211_MANUFACTURED_HOME_PARITY); FHA/VA insurance may require code compliance even where state doesn't. Flag every jurisdiction with `sbco_opt_out_status` (full opt-out / partial / SFD-exempt / default-SFM) and `sbco_residential_opt_out_status` for 1-2 family.