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Build Using Volumetric Modular Construction

Learn about the City of Boston permits and inspections required for building with volumetric modular systems, from application through occupancy.

“Volumetric modular systems” are three-dimensional units constructed in a factory, with building systems and appliances and delivered onsite. Modular systems can be configured to match a variety of site contexts.

Before you can apply for a building permit, your manufacturer must already be licensed by the state and have their facility inspected by a Third Party Inspection Agency. The Process at a Glance section walks through the full sequence.

 

Process at a Glance

  1. If your manufacturer is not yet licensed to operate in the Commonwealth of Massachusetts, they must apply for a license from the Board of Building Regulations and Standards and establish a contract with a Third Party Inspection Agency.
  2. Once licensed, your manufacturer will submit project drawings to the Third Party Inspection Agency.
  3. The Third Party Inspection Agency (TPIA) will submit the drawings to the Office of Public Safety and Inspections (OPSI) for the Board of Building Regulations and Standards.
  4. OPSI will assign your project a Board of Building Regulations and Standards Plan Identification Number and issue a license to the TPIA.
  5. TPIA will inspect the manufacturing facility and project components to ensure compliance with building code requirements. Once your project is deemed compliant, the TPIA will sign off on the construction documents.
  6. The developer or general contractor will apply for a building permit from the City of Boston Inspectional Services Department (ISD), noting the details of manufactured housing components and installation.
  7. ISD will verify the OPSIs assigned unique project number and confirm that the TPIA has signed off on the construction documents.
  8. The developer or general contractor can then begin construction, including installation of volumetric modules.
  9. ISD will inspect connection ports, bolting schedules, electrical, plumbing, and gas tie-ins. Concealed, manufactured components are not re-inspected.
  10. The developer or general contractor will complete construction work and apply for approvals from building, plumbing, and electrical inspectors.
  11. ISD will obtain final approvals from building, plumbing and electrical inspectors.
  12. The developer or general contractor will apply for final inspections and a Certificate of Occupancy.
  13. ISD will conduct final inspections, obtain final approval from the Fire Department, and issue a Certificate of Occupancy.

Who Can Do the Work

Developers or general contractors apply for the building permit and lead the project. You’ll need to work with a manufacturer that’s already licensed under the state’s Manufactured Buildings Program. See Process at a Glance for what that involves.

If your project includes on-site electrical, plumbing, or other trade work, that work must be done by a contractor with a valid, non-expired Massachusetts trade license.

 

Project Permits

Project Permits

Massachusetts regulates modular construction under its Manufactured Buildings Program. Your manufacturer must already have state approval before you can apply for a building permit. See Process at a Glance for the full sequence.

The City of Boston will inspect building components that are not enclosed within the volumetric modules (such as those associated with onsite utility connections). Permits associated with this work may include electrical permits, plumbing permits, and other trade permits.

Long-Form Permit

Covers new construction and structural work, including installing your modular units.
Certificate of Occupancy

Apply after construction and inspections are complete.
Electrical Permits

Covers electrical installations, alterations, and repairs, including gut renovations involving electrical work.
Plumbing Permits

Covers water lines and plumbing work, such as bathroom fixtures and non-structural pipe work.

Related Resources

Related Resources
ICON Architecture Modular Housing Study

ICON Architecture designed common Boston housing types as modular systems, including box sizes and build timelines.
Responses to the 2024 Offsite Construction Request for Information

How 12 modular and panelized housing manufacturers responded to the City's RFI. Not a full list of available vendors.
Fire Prevention Portal

Manage Fire Department permits online.
Inspectional Services Portal

Manage Inspectional Services permits online.
What's My Zoning?

Look up your site's zoning before finalizing modular plans. See district rules and whether you'll need Zoning Board approval.
Housing Innovation Lab

We test new approaches to housing policy, programs, and design to create affordable housing opportunities for all Bostonians.

Who's Involved

Inspectional Services Department

Reviews your building plans and ensures that your manufacturer is approved by the state.
Fire Department

Reviews your building plans to ensure that they meet fire code requirements.
Water and Sewer Commission

Ensures your plans meet specifications for connection to water and sewer systems.
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