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When Building Code Upgrades are Mandatory

February 4, 2022 | By: Mohtady Sherif and Nabi Goudarzi

When a building is damaged, should it be restored to its pre-loss condition, or should it be upgraded to comply with the current building code in effect?  When are building code upgrades mandatory? These questions often arise in a property loss claim during the restoration process. The answers to these questions depend on the specifics of the project and the discretion of the building officials. This article sheds light on the matter with some background information about building code upgrade requirements and when code upgrades are mandatory.

1.    Building Code Compliance for Existing Buildings

The National Building Code of Canada (NBC) is a model code that establishes the design requirements for new construction. This model code has no legal status until adopted, with/without amendments by each Canadian jurisdiction. Over the decades, many provinces adopted the NBC, and a few provinces later utilized the NBC to develop their own provincial building codes to address local needs (Archer, 2003; National Research Council Canada, 2020). Figure 1 shows the building code in effect in each Canadian province and territory.

Buildings must comply with the latest edition of the building code in effect at the time of their construction. Alterations, large renovations, extensions, restorations, additions, and change of use to existing buildings also fall within the scope of the building code with the exception of minor renovations such as kitchen remodeling, replacing flooring and roofing finishes, and painting. The building code is generally not intended to be applied retroactively to enforce new code requirements in existing buildings that are not being altered unless specifically required by other regulations or local bylaws (NBC 2015). However, where a building is undergoing substantial alterations or change of use, upgrades to the building, or at least the altered portion of the building, may be required to comply with the most recent edition of the building code.

The NBC does not contain specific information on how the code should be applied to change of use or to alterations of existing buildings. The Ontario Building Code (OBC) addressed this gap in the NBC by introducing specific provisions applicable to the Change of Use (Part 10) and Renovation (Part 11). Under the OBC, renovations to structures that have been in existence for more than five years fall under the scope of Part 11, which provides “compliance alternatives” that offer some relief from the requirements that are imposed on new construction.

Figure 1: Applicable building codes in Canada.

2.    Types of Building Code Upgrades

When assessing code upgrades for existing buildings, it is important to differentiate between code-compliant and non-code-compliant buildings. Non-code-compliant buildings are those that do not meet the requirements of the building code in effect at the time of construction. Restoration of a non-code-compliant existing building must include code upgrades to meet the latest building code requirements. In this article, code-compliant existing buildings are defined as buildings that met the requirements of the applicable building code at the time of construction but not current building code requirements.

Building code upgrade issues will likely be encountered more and more frequently in the future. Updated editions of the building code have been released every five to six years on average, and Canada’s housing stock is aging. In 2001, it was estimated that 46% of the dwellings in Canada were more than 30 years old. By 2011, that number had increased to approximately 56% (National Research Council Canada, 2020). This means that for more than half of all existing dwellings, the building code in force at the time of construction had been superseded at least four times.

2.1. Structural Upgrades

Structural upgrades are upgrades to existing buildings to enhance the resistance and safety of the structural components. Structures that were built 50 years ago were designed for lower wind pressures and snow loads than required by current building codes. Early building codes had to prescribe wind and snow design loads based on limited research data and historical weather records. As more weather data records have been collected, and as researchers identified various factors that influence design loads such as nonuniform wind pressures and imbalanced snow accumulations, building codes have been periodically updated to improve design accuracy and structural safety. For instance, roof snow loads at one time were considered to simply be equivalent to the ground snow accumulations without considering the effect of the snowdrift. Between the 1960s and 1980s, the effect of snowdrift due to parapets and the effect of multi-level roofs were taken into consideration in building codes. In the 1990s further refinements were introduced to snowdrift calculations, and an associated “rain on snow” load was added.

If the area of damage to a code-compliant building was limited to a relatively small area, it is generally acceptable to restore the area to match existing construction. However, if the extent of damage is substantial, or the structure was a non-code-compliant building, then the restoration design must consider upgrading the structural system to comply with current code requirements. Figure 2 shows the roof of a church that partially collapsed under a snow load that was lower than the design snow load specified by the code in effect at the time of construction. Therefore, this was a deficient existing building. The roof could not have been reconstructed to original conditions and a structural upgrade was required during restoration to bring the roof framing structure into compliance with current code requirements.

Figure 2: Partial collapse of an under-designed church roof.

2.2. Designated Substances Removal Upgrades

From the 1950s and up to the late 1980s, several materials considered revolutionary at the time due to their lightweight and efficient sound and thermal insulative properties became widely used in various construction products including insulation, felt, and pipes. Some of these materials were later discovered to have toxic and/or carcinogenic effects. After the harmful effects of these materials were discovered, laws and regulations were introduced to prohibit or restrict their use and became to be known as designated substances. Building code upgrades are required to replace designated harmful substances from areas being restored or modified with non-harmful code accepted materials.

For example, Asbestos Containing Materials (ACM) were known as efficient insulation materials and were used in several insulation products, from vermiculite insulation in attic spaces and block walls (Figure 3) to pipe insulation and flooring felt and tiles. Asbestos was also used in some wall finishing products such as drywall compounds and gypsum lath panels. Exposure to ACM and other hazardous substances causes life-threatening diseases including, but not limited to, asbestosis, mesothelioma, and lung cancer. In 2018, the Government of Canada passed a regulation prohibiting the use of asbestos and products containing asbestos (Government of Canada, 2018).

Figure 3: Zonolite insulation in an attic space (, 2021)


In Ontario, the handling of hazardous substances is regulated under the Occupational, Health, and Safety Act. The Act prescribes the following chemicals as designated substances: Acrylonitrile, Arsenic, Asbestos, Benzene, Coke oven emissions, ethylene oxide, isocyanates, lead, mercury, silica, and vinyl chloride. The O. Reg. 490/09 is generally concerned with regulating the exposure and processing of designated substances, while the O. Reg. 493/09 is concerned with asbestos on construction projects and in buildings and repair operations. Repair or renovation of buildings constructed before 1990 requires a Designated Substance Survey before commencing demolition activities and often involves handling ACM. Contractors who undertake demolition in older buildings without a Designated Substance Survey may be fined by the Ministry of Labour. These factors add to the cost and extend the schedule of the restoration project.

2.3. Building Envelope Upgrades

Insufficient insulation and protection of the building envelope from air and moisture movement could cause ice damming (Figure 4), deterioration of roofing assemblies, and increased energy consumption of the building. Building and energy codes update the insulation requirements to address the deficiencies and disadvantages of previous insulation practices and to create more energy-efficient buildings. During a major renovation/restoration, upgrading the insulation might be required when the existing insulation contains a designated substance, as discussed earlier, or when the existing insulation does not meet the minimum R-value required by the code in effect.

Figure 4: Ice damming due to insufficient insulation

3.    When are code upgrades mandatory?

How the provinces address code compliance for existing buildings varies. The 2015 NBC provides little guidance on how the code should be applied to existing buildings but refers the user to some further references in the explanatory appendix. Hansen (1984) provides a general discussion on applying building codes to existing buildings. Hansen advocated that designers and building officials should maintain “reasonable” and “constructive” attitudes. Building officials should consider the rationale behind the code requirements to evaluate their relative importance, and then weigh these considerations against the cost of implementation. Upgrades should be implemented to correct serious life safety issues, but it may not be reasonable to impose other requirements intended strictly for property protection or enhanced performance. Essentially, the intent of the NBC is that building officials should exercise good judgment and decide for themselves how the code should be applied to existing buildings. The problem with this approach is that without clear, consistent guidelines pertaining to existing buildings, whether code upgrades are required or not, depends on who reviews the proposals.

3.1. Code Upgrades in Alberta

Under the 2019 Alberta Building Code (ABC), if a building is altered, rehabilitated, refurbished, renovated, or repaired, the life safety and building performance must not be decreased. This provides a little more clarity than the NBC by providing a minimum benchmark. Essentially, whatever you do to an existing building, it should be at least as safe and perform at least as well as before the changes were made. The 2019 ABC also explicitly gives the Authority Having Jurisdiction (AHJ) the discretion to accept existing conditions which are not in complete compliance with the code. Therefore, the ABC reinforces the fact that the AHJ has the freedom to make a judgment call regarding which code requirements must be enforced in existing buildings, which as previously discussed means that code upgrades are not necessarily applied consistently to existing buildings in different jurisdictions.

3.2. Code Upgrades in British Columbia

Similar to the Alberta building code, the 2018 British Columbia Building Code (BCBC) has a general requirement for the safety and performance of existing buildings, stated as: “Where a building is altered, rehabilitated, renovated or repaired, or there is a change of occupancy, the level of life safety and building performance shall not be decreased below a level that already exists.” The 2018 BCBC contains some compliance alternatives developed specifically for designated heritage buildings, and existing buildings adding a secondary suite. These compliance alternatives allow some code requirements to be relaxed. While this provides greater clarity regarding how the code should be applied to existing buildings, the scope is rather limited.

3.3. Code Upgrades in Ontario

In Ontario, the issue of inconsistent application of the building code to existing buildings was addressed in the Ontario Building Code (OBC) by developing Parts 10 and 11. Part 10 applies to buildings undergoing a change of use, and Part 11 applies to buildings undergoing renovation. This ensures code requirements are applied more consistently. Under the 2012 OBC, an addition or renovation to a building more than five years old legally built in compliance with the building code in effect at the time of construction, falls under the scope of Part 11. Part 10 and Part 11 of the 2012 OBC address the requirements for upgrading an existing building, building part(s), or building system(s). They also identify situations where upgrade requirements might be relaxed and the types and applications of acceptable alternative upgrade solutions. Part 11 also provides a comprehensive list of compliance alternatives, which largely eliminates the problem of having building officials make a judgment call regarding the relative importance of current code requirements in order to decide whether code upgrades are needed.

The OBC 2012 recognizes three types of alterations to code-compliant existing buildings: basic and extensive renovations, extensions and additions, and change of use. The need for code upgrades in each category is discussed in the following sections. The flow chart in Figure 5 summarises when code upgrades are mandatory under the 2012 OBC.

Basic renovations include maintaining the existing performance level of all or part of an existing building by the reuse, relocation, or extension of the same or similar materials or components to retain the existing character, structural uniqueness, heritage value, or aesthetic appearance of all or part of the building. If basic renovation or restoration of an existing building is needed, the 2012 OBC does not require the building or building system(s) to be upgraded unless the basic renovation results in any of the following conditions:

  • Reduced performance level of a building system(s),
  • Reduced structural integrity,
  • Reduced safety in a fire scenario, or
  • Creation of an unhealthy environment

Extensive renovations would include replacing or removing existing walls, floors and ceilings. In such cases, the code requires the new building assemblies (e.g. structural elements, fire-resistance elements) to comply with either the current code requirements or the applicable compliance alternatives if compliance alternatives are available under Part 11.

Extensions and additions to existing buildings are required to comply with the requirements of the code in effect. Sometimes, the extension or addition results in a reduction in the performance of the building systems (e.g., plumbing and ventilation); thus, the code requires any part of the building or building system affected by the extension to be upgraded to meet current code requirements.

Change of use includes situations when a building or a building unit is divided into more than one separate unit of the same major occupancy (e.g. basement of a house becoming a separate dwelling unit) or if the building’s major occupancy is changed. The 2012 OBC requires upgrading building part(s) and system(s) affected by the change to comply with current code requirements.


Figure 5: Summary of code upgrades required by the 2012 OBC


Similar to the 2015 NBC and other Canadian building codes, the 2012 OBC gives the chief building official of the authority having jurisdiction the discretion to decide whether a code upgrade requirement can be relaxed or not. Building officials can still make a judgment call when the need arises, but because of the provisions of Parts 10 and 11 of the OBC, this is only necessary in exceptional cases.

4. Conclusion

The bottom line is, as long as the structure was legally built in compliance with the building code in effect at the time of construction and remains unchanged, a building code upgrade is not required. If only basic renovations are proposed, and the structural adequacy and performance levels of the building systems remain the same (including fire protection), and no unhealthy environment is created, building code upgrades are optional. However, extensive renovations, extensions/additions to a building or part of a building or building system, and change of use all require a review of the requirements of the applicable building code to determine the extent of the required upgrades.

Building code upgrades often mean additional costs and longer schedules at each stage, from the analysis and design to the permit application process to construction. The project can get more complicated with older properties where designated substances or prohibited materials may be present because a Designated Substance Survey is required before demolition. If designated substances are found, special measures must be taken to safely remove and dispose of these materials, further adding to the cost and schedule. Early discussions with property owners are essential to raising their awareness of the added complexity should code upgrades be required and to help property owners set reasonable expectations, thus, minimizing the probability of conflicts and achieving higher client satisfaction.

5. References

Archer, J. W. (2003). A Brief History of the National Buildings Code of Canada. Journal of the Ontario Building Officials Association, 24–25.

Zonolite Insulation.

Government of Canada (2018). Prohibition of Asbestos and Products Containing Asbestos Regulations: SOR/2018-196. Canada Gazette Part II, 152(21), 3371–3532.

National Research Council of Canada (2020). Model Code Adoption Across Canada. Natural Resource Canada.

National Research Council of Canada (2015). National Building Code of Canada

Ministry of Municipal Affairs and Housing (2012). Ontario Building Code 2012.

Hansen, A. (1984). Applying building codes to existing buildings. Canadian Building Digest -230.

ABC (2019). National Building Code – 2019 Alberta Edition. National Research Council of Canada

Ministry of Municipal Affairs and Housing (2018). British Columbia Building Code 2018.