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Code Compliance for Modular Construction 

Every new building in Canada has to comply with building codes—whether site- or factory-built. Factory-constructed buildings require an “off-site review” to show the local authority that the elements constructed in the factory comply with code. This is typically accomplished through certifying the entire factory construction process to the CSA A277 certification standard—just like building products installed in buildings are certified. Find out how this works and the how the codes and standards apply.

National-Codes books


National codes are model codes and their provisions only become requirements when they are adopted by the local authority having jurisdiction. This means that all buildings, including factory-built buildings, must comply with the locally applicable building codes and regulations in effect, and that they should be checked, verified and inspected against the requirements in the location they are built in.

When it comes to local requirements for factory-based construction, there are differences across the provincial and territorial codes. Some jurisdictions require CSA A277 certification to verify that factory-constructed buildings comply with local requirements.

This table shows where CSA A277 certification is REQUIRED by a province or territory—as in Alberta, Quebec and the Yukon—and where it is RECOGNIZED or ACCEPTED—either by provincial/territorial regulation or through municipal policy or regulation.

How does certification work?

Certification to CSA A277 must be conducted by a certification body accredited by the Standards Council of Canada and recognized by the authority having jurisdiction. The certification body provides:

  • certification of the factory’s quality system and quality program, and
  • certification of the buildings, modules, or panels produced in the factory as complying with applicable local regulations (including requirements for professional involvement where applicable)

The certification body oversees the in-plant quality process, including identification of qualified personnel and responsibilities, sign-offs and record-keeping, and conducts annual audits and random inspections.

This SCC website lists the accredited certification bodies for a given scope. 

To find certification bodies accredited for in-factory construction, it helps to know the International Classification of Standards code for buildings and systems: 91.040.99.

Scope of certification/accreditation

The CSA A277 standard can be used to certify all types and sizes of buildings and occupancies, as well as modules and panels. The buildings, modules and panels can be constructed of any building material (including used materials), provided they comply with the building code or regulation in effect at the installation location.

The buildings, modules or panels that can be certified in a particular factory are specified in the scope of the factory’s certification—for example, a factory’s scope could include just Part 9 single-family houses, or all Part 9 buildings, or Part 9 buildings and Part 3 assembly occupancy.

In addition, the certification body’s accreditation similarly specifies the products it is eligible to certify, which depends on the qualifications of the certification body to evaluate design and construction of buildings of varying degrees of complexity.

In other words, the types of buildings, modules or panels for which a factory is certified may be limited by the capabilities of the factory, or by the capabilities of the certification body.

Information on factory certifications can be found on the websites of the certification bodies, and information on the qualifications of the certification bodies can be obtained from the Standards Council of Canada.

Inspections and documentation

Building elements that are built on-site (e.g. the foundation) are inspected at the site. Elements built in the factory are constructed and inspected in the factory for conformance to the local requirements in effect at the destination site. The factory construction process and the need to satisfy the procedures outlined in CSA A277 result in detailed documents available to support the permit process.

Every building produced in a certified factory has a unique serial number assigned to it, and the associated documentation includes a travel log with the factory checklist, all inspections and testing completed, shipping documentation, and all the design documents.

Design documents include design schedules for roof and floor trusses, ridge beams, foundation details, plumbing and electrical schematics, heat loss calculations, ventilation designs, and cross-section and floor plan drawings. Where other specific documents are required (e.g. letters of assurance) they are also supplied with the building when shipped.

Standards for factory construction

Standards applicable to factory-constructed homes and buildings include:

CHBA's  "Working with Modular" Webinar Series

“Working with Modular” is a six-part webinar series highlighting the features and benefits of modular construction. The content is designed to inform on-site builders and developers, code officials, municipal planners and housing specialists, government departments, lenders, warranty providers and other stakeholders engaged in the residential construction industry. We would like to acknowledge the support of the Canada Mortgage and Housing Corporation in the development of the webinar series as well as Altus Group for their work in the project.

To watch the videos in full-screen mode, click on the YouTube icon in the bottom right of the video after you hit play.


For more information contact:


Frank Lohmann

Building Science
613-230-3060 ext. 231

Code Compliance for Modular Construction
(January 26, 2023)


This webinar is predominantly aimed at building officials as it will describe how codes compliance is verified for factory-constructed buildings including provincial variations. The webinar will also explain how the factory certification according to CSA A277 works and what that means for code officials.