International Residential Code
Massachusetts enforces the 2021 IRC
The 2021 International Residential Code (IRC) has been in force in Massachusetts since Oct 11, 2024. It applies statewide. Adopted by Board of Building Regulations and Standards (BBRS). The legal citation is 780 CMR 51.00, s. R101.1.
Record of adoption
Edition in force
2021 IRC
Massachusetts Residential Code (780 CMR 51.00), Tenth Edition, Residential Volume
Verified
- In force since
- Legal citation
- 780 CMR 51.00, s. R101.1
- Adopted by
- Board of Building Regulations and Standards (BBRS)
- Second reading
- Applies
- Statewide
- State amendments
- Major
- Also called
- 780 CMR 51.00, Residential Volume, Massachusetts Amendments to the 2021 International Residential Code
Applications filed through Jun 30, 2025, could use either the 10th or the 9th Edition; after that only the 10th Edition applies. The text on mass.gov is an unofficial copy.
Exceptions
- On a city or town’s request the BBRS may adopt more restrictive local standards where it finds special conditions (G.L. c. 143, s. 98); no individual local variations were checked.
Coming next
- 2024 IRCPartialNo date yetIn development780 CMR 51.00 (11th Edition, in drafting)
The BBRS 11th Edition Residential Code Subcommittee is reviewing 2024 IRC chapters (meeting Oct 1, 2026); no adoption or effective date was found.
How Massachusetts adopts the IRC
The residential volume (780 CMR 51.00) is adopted by the BBRS together with the base volume, by regulation under G.L. c. 143, s. 94 after statutory public hearings; no legislative approval step appears in s. 94. Paragraph (h) directs revision at least once every five years. The 10th Edition residential volume took effect Oct 11, 2024; 11th Edition IRC chapter reviews are under way.
Cycle. Irregular, tied to the 780 CMR editions: 9th Edition (2015 I-Codes) then 10th Edition (2021 I-Codes, effective Oct 11, 2024); 11th Edition drafting uses the 2024 IRC.
Laws, rulings, and other actions
- Other actionBBRS extension of the 9th/10th Edition concurrency period
After a BBRS hearing on Dec 2, 2024, the concurrency period originally set to end Jan 1, 2025, was extended to Jun 30, 2025 (announced Dec 5, 2024); only the 10th Edition applies after that.
- LegislationSt. 2021, c. 8, An Act Creating a Next-Generation Roadmap for Massachusetts Climate Policy
Directs DOER, with the BBRS, to develop a municipal opt-in specialized stretch energy code (G.L. c. 25A, s. 6(14)), adds it to the specialized codes in G.L. c. 143, s. 96, enlarges the BBRS from 11 to 15 members and changes a timing phrase in s. 97 to 45 days.
Enacted Mar 26, 2021 (date from the legislature page metadata)
malegislature.gov (opens in a new tab)
How it was checked
Verified
Two separate readings of the state’s own record agree, and the passage is on file word for word.
Read twice: a second, blind reading of the state’s record agreed with the first on .
The state’s record was last read on , from five source pages.
Evidence 5 sources
Sources for the record itself come first, the state’s own records ahead of others. A label marks a source about something else, such as an exception. A source marked secondary is not the state’s own record.
“by reference the International Residential Code, 2021”
“780 CMR 51.00: Massachusetts Residential Code, otherwise known as the Massachusetts State Building Code”
“Tenth Edition, Residential Volume.”
780 CMR 51.00: Massachusetts Residential Code (Amendments to the 2021 International Residential Code), Section R101.1 (unofficial copy)Commonwealth of Massachusetts (Mass.gov), Board of Building Regulations and Standardsmass.gov (opens in a new tab)Administrative codeRetrieved “The tenth edition building code became first effective on October 11, 2024”
“The tenth edition code is based on modified versions of the following 2021 International Codes (I-Codes)”
Tenth edition of the MA State Building Code 780Commonwealth of Massachusetts (Mass.gov), Board of Building Regulations and Standardsmass.gov (opens in a new tab)Agency pageRetrieved “Effective October 11, 2024, the 10th Edition of the State Building Code will take effect.”
10th Edition of the State Building Code Board of Building Regulations and StandardsCommonwealth of Massachusetts (Mass.gov), Board of Building Regulations and Standardsmass.gov (opens in a new tab)Agency pageRetrieved About an exception
“more restrictive standards than those established by the state building code”
“reasonably necessary because of special conditions prevailing within such city or town”
General Law - Part I, Title XX, Chapter 143, Section 98Massachusetts General Court (malegislature.gov)malegislature.gov (opens in a new tab)StatuteRetrieved About the note
“The 9th Edition of the Building Code will apply concurrently with the 10th Edition until June 30, 2025.”
Concurrency period for 9th and 10th Edition of the State Building Code extended until June 30, 2025Commonwealth of Massachusetts (Mass.gov), Board of Building Regulations and Standardsmass.gov (opens in a new tab)Agency pageRetrieved