CSA A277 is not a building code. It is a certification procedure: an independent, accredited agency checks a factory's quality system and inspects its products, so the closed-in walls, floors and roofs of a module do not have to be opened on site. The building code still applies in full, and anything finished on site, from the foundation to the service connections, is outside the A277 certificate and needs its own permits and inspections.
For a housing manager, that split matters more than the standard itself. It decides who inspects what, which papers you need at handover, and how a factory-built home fits the inspection stages your funder expects. This guide explains how factory-built homes are regulated in Canada and gives you a list of what to ask any modular builder for. It is general information, not legal advice. Rules differ by province and by funder, so confirm the details with your ISC regional office, CMHC, your building inspector and your lands office.
What is CSA A277, and what is it not?
The problem A277 solves is simple. The National Building Code of Canada 2025 says it "applies to both site-built and factory-constructed buildings." But once a module arrives on site, many of its wall, roof and floor assemblies are already closed in, and their components cannot be inspected.
The Code's explanatory note describes A277, "Procedure for certification of prefabricated buildings, modules, and panels," as a procedure "whereby an independent certification agency can review the quality control procedures of a factory and make periodic unannounced inspections of its products." The same note is blunt about its limits: "The standard is not a building code, only a procedure for certifying compliance of factory-constructed components with a building code or other standard."
British Columbia's information bulletin B15-01 sets out the four things the standard covers:
- certification of the factory quality program
- certification of the built product
- auditing of the factory quality program
- in-factory inspection of the built product
In plain terms: the certification agency approves how the plant builds, approves what it builds, keeps auditing the plant, and inspects product on the line. The plant is checked against a code. A277 is the method of checking, not the rulebook. (For a builder's plain-language overview of the standard, see CSA A277 explained.)
How does A277 relate to the National Building Code and provincial codes?
The National Building Code is a model code. Its preface states that "provincial and territorial governments have the authority to enact legislation that regulates building design and construction within their jurisdictions," either by adopting the national code or by modifying it. The preface also notes that the Code "does not set out who is responsible for assessing conformity"; that is left to provincial and territorial law. So how much weight an A277 label carries depends on where the home is going.
Provinces handle it differently:
- Alberta. STANDATA 23-BCV-002 (May 2024) quotes the National Building Code – 2023 Alberta Edition: factory-constructed buildings built after 1 May 2024 and certified under CSA A277 "by an organization accredited for this purpose by the Standards Council of Canada are considered to comply with this Code." It also accepts other routes, including verification by registered architects or engineers, or inspections by the authority having jurisdiction.
- Manitoba. Inspection and Technical Services bulletin ITS 23-001 says a label showing National Building Code compliance under A277 gives the accepting authority "some assurance that the concealed components do not require re-inspection on site." It also notes a permit may be required when a factory-constructed building is put up or moved.
- British Columbia. Bulletin B15-01 (2015, the most recent BC bulletin on the subject we found) says A277-certified buildings installed in BC "are still required to be designed and built to the BC Building and Plumbing Codes" or to the separate CSA Z240 MH mobile home standard.
- Saskatchewan. The Plumbing Code Regulations exempt from a plumbing permit the plumbing inside a structure that conformed to CSA A277 when it was built. That exemption ends once the plumbing is permanently connected to a communal water or sewer system and then extended, altered or repaired.
Do not confuse A277 with CSA Z240 MH, the manufactured (mobile) home series. The National Building Code warns that a label showing a house complies with Z240 MH "can NOT be taken as an indication that the house necessarily complies with the building code" where it will be sited. Ask your builder which standard each unit is certified to. The answer should be on the label.
On reserve, ISC-funded projects follow ISC's Protocol for ISC-Funded Infrastructure (modified 17 November 2025). It points to provincial or territorial building rules and states: "In the absence of provincial or territorial statutes and regulations pertaining to buildings, the national codes will apply." Check with your region which code and edition it expects, and make sure the builder's certification names that code.
What is inspected in the plant, and what on site?
The clearest line comes from BC's bulletin: A277 "does not cover portions of the buildings or services that are not completed in the factory. It does not address the transport of buildings or their erection at the installation site." Use that line to sort every task on your project.
Usually covered by the factory certification (if completed in the plant):
- Floor, wall and roof framing that is closed in before shipping
- Insulation, air and vapour barriers inside closed assemblies
- Plumbing, wiring and ductwork roughed in and concealed in the plant
- Interior finishes and fixtures installed before the module leaves
Outside the certificate, so it needs site permits and inspections:
- The foundation, piles or pad, and anchoring the units to it
- Joining sections together on site (marriage walls, roof joins, any trim or siding finished on site)
- Connections to water, sewer and power. In Saskatchewan, for example, the Plumbing Code Regulations require a permit to connect a plumbing system to communal sewage works or waterworks
- Any work the builder leaves unfinished for local trades to complete
- Damage repair after transport
BC's bulletin, writing about Z240 homes, describes the same principle: site preparations, "which include siting, foundations, and mountings as well as connections to services and installation of appliances," must comply with the code. Electrical work is often permitted separately. In Manitoba, for example, ITS 23-001 says Manitoba Hydro enforces the electrical code outside the City of Winnipeg, and the branch "does not issue electrical permits or labels for buildings that are to be hooked up to an electrical utility."
How does factory inspection fit your funder's inspection stages?
Funders set inspection stages with site building in mind. ISC's protocol asks recipients to have housing projects "inspected by certified inspectors to confirm compliance with code requirements at the following stages (as a minimum): site, foundation, framing and completion." CMHC's building code compliance page for First Nation housing lists a pre-backfill inspection, a pre-drywall inspection covering "framing, rough-in and insulation/vapour barriers," and a final inspection, each needing a Certificate of Building Code Compliance.
With a factory-built home, the site, foundation and completion stages still happen on your land. The framing or pre-drywall stage happened in the plant weeks earlier, inside walls that are now closed. The National Building Code note explains why the A277 label exists: so the accepting authority can be assured that concealed components do not need re-inspection on site. Whether your funder and inspector accept the label and plant records for that stage is their decision, not the builder's.
So settle it before the plant starts:
- Send your funder and inspector the builder's certification details and ask in writing how the framing or pre-drywall stage will be signed off.
- Ask whether your inspector wants to visit the plant while the walls are open. If so, book it into the production schedule.
- Agree who signs each certificate and what documents back it up, then file that agreement with the project records.
What does the label tell you, and what can void it?
The label is the evidence. The National Building Code note refers to "the label of an accredited certification agency" showing that compliance with the National Building Code "has been certified using the CSA A277 procedure." BC's bulletin makes the same point about a label showing compliance with the BC Building Code. Either way, the label should name the code the unit was certified to. Check that it matches the code your project has to meet.
A label can also lose its value. Manitoba's bulletin warns: "Where certification materials are unavailable or have become voided due to alteration, the land authority may require further documentation." In practice:
- Photograph every label on every section the day it arrives, and record the serial numbers in your project file.
- Never remove or paint over a label.
- Before anyone cuts into a factory wall, floor or roof (to add a window, move plumbing or run a new circuit), call your inspector. Changes made later are site work and may need a permit. Saskatchewan's plumbing permit exemption, for example, ends once connected plumbing is extended or altered.
- Keep the certification paperwork with the asset records for the life of the home. A future renovation, insurance claim or sale may depend on it.
What should a housing manager ask a modular builder for?
Use this list in your request for proposals and again at handover:
- The standard and the code. Which standard each unit will be built to (A277 or Z240 MH), and which code and edition the certification will name.
- The certification body. Its name, and confirmation that it is accredited for A277 by the Standards Council of Canada. Alberta's code wording, for example, requires an organization "accredited for this purpose by the Standards Council of Canada".
- Labels. Where the labels go on each section, what they say, and a list of serial numbers matched to units.
- Plant inspection access. Whether your inspector or project representative can visit during production, and when the walls will be open.
- A scope split in writing. A list of what is finished in the plant and what is left for the site, so every site item gets a permit and an inspection.
- Site drawings. Foundation or pad design, anchoring and connection details, stamped by an engineer where your province or funder requires it.
- Set-up instructions. The builder's instructions for joining sections and finishing on site, so your inspector can check site work against them.
- Handover package. Final plans, labels and serial numbers, appliance and equipment manuals, warranty terms, and any plant inspection records the builder can release.
If funding is still open, the builder cannot answer that question for you. See our guide to funding modular buildings for First Nations for the programs and who to contact.
Where does a modular builder fit in?
Herauf Modular builds homes and community buildings as finished sections indoors in its Saskatchewan and BC plants, then delivers and sets them on site. Every unit meets or exceeds CSA A277 and the National Building Code for climate zones 6 through 8. Most builds are manufactured and delivered in about 16 weeks, with foundations, pads and services prepared on site at the same time. That is why the site-side permits and inspections above need to be planned from the start, not after the units arrive. For more on how factory building and delivery work for remote communities, see modular Indigenous housing.
Herauf does not administer funding, does not apply on a community's behalf and cannot promise eligibility. We can walk your housing team and inspector through what is built in the plant, what is left for the site, and what paperwork comes with each unit. Herauf replies to enquiries within one business day: contact us.
This guide is general information, not legal or financial advice. Program rules change: confirm the details with the program, your Indigenous Services Canada regional office or CMHC before relying on them. Herauf does not administer any program or apply on a community's behalf.