Massachusetts 780 CMR 10th Edition: what changed for your drawings

The Massachusetts State Building Code, 780 CMR, moved to its 10th Edition in October 2024, and the transition period is now over. If your office still has 9th Edition details in its sheet templates, or still has general notes that reference the 2015 I-Codes, this is a good time to clean them up. This post covers what the 10th Edition is based on, how the transition worked, the Massachusetts-specific pieces that most often affect a permit set, and how energy code tiers differ from town to town.

Effective date and the end of concurrency

The 10th Edition first took effect on October 11, 2024. The Board of Building Regulations and Standards (BBRS) allowed a concurrency period, during which a permit application could follow either the 9th or the 10th Edition, but not a mix of the two. That period was extended once and ended on June 30, 2025. Since July 1, 2025, the 10th Edition is the only version of 780 CMR that applies to new building permit applications. The applicability and concurrency language is in 780 CMR 102.

Two practical points follow from that. First, a set that was permitted under the 9th Edition stays on the 9th Edition, but if a permit lapses (see 780 CMR 105.5 for permit expiration), a new application will be reviewed under the 10th. Second, mixing editions was never allowed, so a set that cites 2021 IBC sections for egress and 2015 IECC sections for energy is likely to draw a comment.

The base model codes

The 9th Edition was built on the 2015 International Codes. The 10th Edition moves to modified versions of the 2021 International Codes. According to BBRS, those are:

• International Building Code (IBC)
• International Residential Code (IRC)
• International Existing Building Code (IEBC)
• International Mechanical Code (IMC)
• International Energy Conservation Code (IECC)
• International Swimming Pool and Spa Code (ISPSC)
• International Fire Code (IFC), in the portions the building code references

The structure follows the 35 chapters and appendices of the 2021 IBC, with selected chapters replaced by Massachusetts-specific text or by other I-Codes. The adoption language is in 780 CMR 101.1. Residential work is in a separate chapter: Chapter 51, the Massachusetts Residential Code, adopts the 2021 IRC with Massachusetts amendments. Most new code language your team will run into comes from the six-year jump in the I-Codes, not from Massachusetts changes.

Massachusetts amendments that shape a permit set

Massachusetts publishes its changes as an amendment document that is read alongside the 2021 I-Codes. A few areas are worth special attention because they differ from what teams used to working in other states expect.

Chapter 1 is unique to Massachusetts

The IBC's Chapter 1 on administration is replaced entirely. Permit applications, construction documents, construction control, licensing of construction supervisors and the duties of the building official all follow Massachusetts rules. For projects under construction control, the registered design professional's role and the required affidavits and documentation are set by 780 CMR 107.6. Make sure your cover sheet and code summary describe the project in Massachusetts terms, not generic IBC terms.

Structural loads

Massachusetts sets its own climatic and geographic design values in the structural chapter amendments (Chapter 16), including basic wind speeds by municipality in 780 CMR Table 1604.11 and ground snow loads. Check that the design criteria in your structural general notes come from the Massachusetts tables for the project's town rather than from the national maps alone.

Existing buildings

Work on existing buildings follows the 2021 IEBC with Massachusetts amendments. Alterations, additions and changes of occupancy are a large share of Massachusetts permit work, so confirm that the code summary names the IEBC compliance method you used and that the drawings support it.

Other codes that sit beside 780 CMR

The building code is not the only regulation a Massachusetts reviewer applies. Three separate codes come up on nearly every commercial set:

• Fire. Massachusetts is an NFPA state. The fire code is 527 CMR 1.00, which is based on NFPA 1 with Massachusetts amendments. Fire department review, fire alarm and sprinkler requirements often point to 527 CMR and the NFPA standards it references, not the IFC.
• Accessibility. The Architectural Access Board's rules, 521 CMR, apply in addition to the federal ADA Standards. Where the two differ, the design generally has to satisfy both, so check your accessible route, toilet room and parking details against 521 CMR as well.
• Plumbing and electrical. Plumbing is governed by the state plumbing code, 248 CMR, and electrical work by the Massachusetts Electrical Code, 527 CMR 12.00. They have their own boards and their own inspectors.

Energy code: Base, Stretch and Specialized

Energy is the area where the town your project is in matters most. Massachusetts has three energy code tiers, and each municipality adopts one:

• Base energy code. This is the energy provisions of 780 CMR, built on the 2021 IECC with Massachusetts amendments. It applies in towns that have not adopted a stretch tier.
• Stretch energy code. This is a stronger set of requirements maintained by the Department of Energy Resources (DOER) in 225 CMR 22.00 (residential) and 225 CMR 23.00 (commercial). Most Massachusetts municipalities have adopted it.
• Municipal opt-in Specialized code. This builds on the stretch code and adds net-zero-oriented pathways for new construction, generally steering projects toward all-electric design, or toward fossil-fuel systems with on-site solar and electric pre-wiring. It is also in 225 CMR 22.00 and 23.00.

Towns move between tiers by local vote, and a move takes effect on a set date. DOER keeps the official list of which towns are on which tier. Before you finalize HVAC, water heating and envelope selections, check the project's town against the current list and note the tier on the energy compliance sheet. A residential set built to the Base code in a Specialized town will need significant rework.

The tier belongs to the legal municipality, not to the postal address. Many Massachusetts addresses use village names (Hyannis is part of Barnstable, for example), so confirm which town the parcel is in.

Common plan review comments after the switch

• The code summary references the 9th Edition or the 2015 I-Codes; revise it to the 10th Edition.
• Design criteria do not match the Massachusetts snow and wind values for this municipality.
• Identify the energy code tier and compliance path for this municipality.
• The specialized code applies in this town; show how the project complies.
• Provide 521 CMR accessibility compliance in addition to the ADA Standards.
• Fire protection notes cite the IFC; revise them to reference 527 CMR and the applicable NFPA standards.
• Provide construction control documentation per 780 CMR 107.6.

Pre-submission checklist

1. The cover sheet and code summary cite 780 CMR 10th Edition and the 2021 base codes.
2. No details, notes or specifications still reference 9th Edition or 2015 I-Code sections.
3. Residential projects cite Chapter 51 and the 2021 IRC as amended.
4. Structural design criteria use the Massachusetts values for the project's town.
5. Existing-building work names the IEBC compliance method.
6. The energy tier is confirmed against the current DOER list for the legal municipality, and the compliance path is shown.
7. Accessibility is checked against both 521 CMR and the ADA Standards.
8. Fire protection references 527 CMR and the NFPA standards it adopts.
9. Construction control requirements are identified where they apply.

Where PermitPrep.AI fits

PermitPrep.AI is a supplement for code consultants. For Massachusetts projects it reviews your drawing set against the 10th Edition as adopted, along with 521 CMR accessibility and the 527 CMR 1.00 fire code. Energy code tiers are covered town by town for all 351 municipalities, so the report names the Base, Stretch or Specialized tier that matches the project's town (Specialized multifamily notes the Passive House pathway). It does not choose or check a specific compliance pathway such as HERS or performance versus prescriptive, and it does not claim town-specific snow values or construction-control reviews. Addresses that use a village or neighborhood name, such as Hyannis or Dorchester, resolve to their town; the few village names that straddle a town line are reported as unknown so you can confirm the town rather than having it guessed. Findings cite the sheet and code section, and a full drawing set takes about 20 minutes. Free trial: 2 reports, no credit card required.