Standards ensure off-site built tiny homes deliver safety and efficiency

As many communities and potential homeowners struggle with housing affordability, tiny houses have emerged as part of the solution. Assuring these tiny houses deliver the same level of safety and efficiency of other permanent housing solutions is essential. Local building codes and the International Residential Code (IRC) and its Appendix AQ provide for the necessary requirements. Often, tiny houses are constructed away from their ultimate resting place — through off-site construction techniques.

Off-site construction plays a vital role in the building and manufacturing industries by mitigating costs, consolidating labor needs, and saving time. The surge in off-site construction, along with the growing interest in tiny homes and minimalistic living, have all made an impact on the housing market in recent years.

What are the benefits of off-site construction?

Off-site construction, also known as modular, prefabricated or industrialized construction, has been around for some time and has not been without criticism for structural conformity. However, a recent report from McKinsey & Company shared that the combination of lightweight materials and digital planning and production technologies could enable the industry to attain new levels of quality, variability, and efficiency.

The advancement of off-site construction is progressing at a rate that continues to grow both its reputation and demand, viewed by some as the future model for all construction. Valeria Montjoy of ArchDaily believes that because it is a centralized process, off-site construction is faster, safer, more regulated, and requires less coordination efforts, which results in higher productivity and improved quality control.

This translates into major benefits for both manufacturers and contractors including reduced costs, time saved, and less labor required. According to an additional study done by McKinsey & Company, modular construction can speed up the building process by as much as 50 percent and cut costs by up to 20 percent. Additionally, an article by Modular Housing notes that materials built in a factory are cut according to the software input, reducing mistakes and waste.

Building tiny houses off-site requires different approaches

Right now, the building and approvals process for tiny homes follows a wide variety of approaches — not all leading to the protections consumers and governments expect. In many cases, tiny houses are built to recreational vehicle standards designed to support only temporary or seasonal occupancy. Others are built to requirements in the IRC. When built off-site, verifying compliance with code requirements means shifting the process into the factory.

To address the shift towards factory-based compliance processes, the International Code Council and its family of solutions have developed a suite of tools including standards, product evaluation, accreditation and third-party plan review and inspection. For most forms of off-site construction, the building must comply with the building code requirements in the jurisdiction where it will ultimately be placed.

What is the International Residential Code and Appendix AQ?

The International Residential Code (IRC) is a model code developed by the International Code Council that establishes minimum requirements to provide for the affordability, structural strength, means of egress, stability, sanitation, light and ventilation, energy conservation and safety to life and property in one and two-family detached dwellings and townhouses. Members of the tiny house industry and the building safety industry recognized that to be a viable housing option for permanent occupancy, tiny houses must adhere to the health, safety, and efficiency requirements for residential structures. This is achieved through the application of the IRC to these structures. To provide additional flexibility for tiny houses while recognizing the limited space availability, Appendix Q was introduced in the 2018 edition of the IRC (in the 2021 IRC, the appendix is Appendix AQ).

New standards for off-site construction and building tiny homes

Because off-site construction requires compliance to be verified in the factory instead of at the final job site, a different approach is required. In partnership with the Modular Building Institute (MBI), the Code Council developed two new standards to address all facets of the off-site construction process. ICC/MBI Standard 1200 covers planning, designing, fabricating, transporting and assembling of commercial and residential building elements and ICC/MBI Standard 1205 addresses the inspection and regulatory process. An additional off-site construction standard (ICC/MBI Standard 1210) to address mechanical, electrical and plumbing systems, energy efficiency, and water conservation is currently in development.

How do tiny house certifications and inspections work?

While the adoption and use of standards is important, verifying that they are being followed is equally important. Just as there are multiple standards for tiny houses, there are varying certification and verification requirements.

In the case of tiny houses that are built to comply with the IRC, there are long-standing inspection processes. If the tiny house is going to remain in the same place that it was built, periodic inspections can be conducted by the local code official (just as they do for other residential buildings). For tiny houses built in a factory, many states have programs specifically focused on off-site construction including modular housing.

The off-site construction approvals process involves either governmental plan reviewers and inspectors or approved third-party providers that review plans and inspect units in the factory. The factories also must maintain and follow a quality assurance plan approved by the state or third-party. The third parties often must retain certifications or accreditation that demonstrate their competence in performing such roles.

Manufactured housing has its own plan review and inspection process under the auspices of the Department of Housing and Urban Development that sometimes delegates authority to individual states. Again, plan reviews and inspections are conducted by government employees or approved third-party providers.

Tiny houses should put safety first

Tiny houses offer a wide range of opportunities for manufacturers and contractors to save time, materials, and labor as well as address the availability and affordability of housing. However, manufacturers, contractors, and code officials should make sure that their objectives are being met without sacrificing safety and efficiency. To aid in this journey, the International Code Council, together with the Tiny House Industry Association, has developed model legislation to ensure that those who wish to ‘live tiny’ can put safety first.