A new standard for the design of offsite modular construction created by the CSA Group is made to instill more trust in the process, which could accelerate the build-out of factory-made housing.

The standard, under the name Z251:26, establishes a common technical framework for designing volumetric modular buildings, which involves parts built in factories that are transported to a site for assembly. It complements the National Building Code of Canada, setting recommendations and guidance for topics such as structural design, manufacturing and environmental separation.

Z251:26 can help align safety, quality and innovation in the modular sector, Dwayne Torrey, the director of construction and infrastructure standards at the CSA, said in an interview with RENX Homes.

The CSA is a Toronto-based non-profit that develops safety standards and performs testing, inspection and certification, and created guidelines for modular construction in the past.

The organization began paying more attention to modular standards over the past decade because modular can also be used for midrise and highrise projects, Torrey said. But what was missing in its list of standards, he added, was one focused on the design of modular structures.

The growth of modular construction in Canada will “depend on trust,” Torrey said, and as many still have questions and uncertainty about the technology, standards can build that trust.

Building a foundation of trust in volumetric modular buildings

The standard defines fundamental elements of volumetric modular construction, such as how beams, floors and ceiling assemblies should be used, and how modular systems can be stacked.

Disclosure of design tolerances, ensuring safe transportation of modules and adhering to local energy efficiency codes are also emphasized in the document.

Those unfamiliar with modular construction, Torrey said, may have questions about performance, quality and safety. Following closely to Z251:26 sets assurances that modular projects are being designed and delivered using recognized technical requirements, he continued.

Using a recognized guide makes it easier for regulators to review projects, for developers to invest in modular technology, and for project proponents to have a clearer picture of the return on investment, Torrey explained.

'Confidence and consistency' in modular construction

While the standard was not written specifically for residential builds, it could have ramifications as Canada looks to the method for its housing needs. Modular construction has been pushed by the Canadian government and industry groups such as the Canadian Home Builders' Association for its speed, consistency and efficiency, which would alleviate the pressures faced by the construction and housing sectors.

Z251:26 can help “create that confidence and consistency needed to support the broader adoption” of modular homebuilding, Torrey said.

The standard is of value to designers, architects, developers and manufacturers, Torrey said. Regulators may find it handy as CSA standards are often referenced by the government.

Though the CSA’s standards cannot solve Canada’s housing troubles on their own, they can help remove uncertainty and enable modular construction to scale up more effectively to address the problem, Torrey said.

The arrival of Z251:26 complements the CSA’s other standards for modular construction, such as one that covers the process for delivery of volumetric modular buildings titled Z250:21.

There is more work on modular standards taking place in the CSA, Torrey said, specifically development of a guideline for construction in Northern Canada as the region’s geography demands special needs for transporting and installing modules. It is planned to be released in early 2027.