National Building Code: Often Overlooked Parts in Small Residential Projects
- coraliefortin076
- Oct 1
- 5 min read
When embarking on a residential construction or renovation project—whether it's a house, a cottage, or a garage—it's easy to focus solely on aesthetics, functionality, or cost. Yet, one fundamental aspect is often underestimated: compliance with the National Building Code (NBC), and more specifically, its many, sometimes complex, technical requirements. These requirements don't just apply to large buildings or commercial projects. They also apply—and sometimes surprisingly—to smaller residential projects, even those deemed "simple" or "modest."
At Plan Maison Québec, we work daily with clients across Canada to design compliant residential plans that are built to last, safe, and adapted to the latest regulatory requirements. An important part of this work involves raising our clients' awareness of aspects of the Code that are often overlooked or ignored, but which can have serious consequences if not respected.
In this article, we shed light on these often overlooked sections of the National Building Code in small residential projects, and explain why it's crucial to consider them in the early planning stages. Whether you're a homeowner, self-builder, or contractor, this information can help you avoid many mistakes... and unnecessary expenses.
The regulatory framework: CNB + Quebec amendments
Before going into detail, let's briefly review the regulatory context. In Quebec, the Construction Code falls under the Building Act and is enforced by the Régie du bâtiment du Québec (RBQ). The "Building" chapter of the Quebec Construction Code consists of the National Building Code of Canada 2020 (NBC 2020), to which are added specific provincial amendments.
Indeed, the amendments adopted by Quebec may adjust or strengthen certain requirements, particularly with regard to accessibility, structural safety, energy efficiency, and fire protection.
Since April 2025, the updated version of the Construction Code will gradually come into effect for all residential construction or conversion projects. Even small projects are not exempt from meeting its minimum requirements, particularly with regard to energy efficiency, safety, ventilation, and structure.
Energy efficiency and air tightness
One of the most frequently overlooked elements in small-scale residential projects is compliance with Chapter I.1 of the Code, which governs energy efficiency. Even when it comes to an addition or a garage, the project must meet specific requirements for insulation, the performance of openings (doors, windows), airtightness, and ventilation.
Many homeowners are unaware that blower door tests may be required. Without a well-designed plan, junctions between walls, foundations, roofs, or openings become weak points that can lead to energy loss. At Plan Maison Québec, we integrate these constraints from the design phase to optimize overall energy performance and avoid unpleasant surprises.
Accessibility: an aspect too often overlooked
Accessibility isn't just a concern for public buildings. For several years now, the NBC and the Quebec Code have included specific accessibility and adaptability requirements, even in certain residential projects, particularly intergenerational or rental housing.
Requirements may concern the width of doors and hallways, step-free access to the entrance, clearances around sanitary fixtures, or even the ability to accommodate the future installation of adapted equipment. Failure to anticipate these requirements can limit the building's future use or reduce its resale value.
Fire safety and emergency exits
The NBC contains strict rules regarding fire protection, even in private residences. One of the often overlooked aspects is the fire resistance of partitions separating certain areas, such as attached garages, converted attics, or basements.
It is also crucial to comply with the minimum dimensions for emergency exits, particularly windows in bedrooms located in the basement or upstairs. Failure to comply with these requirements can render a room non-compliant and even unusable as a bedroom, depending on the municipality.
At Plan Maison Québec, we pay particular attention to these elements to guarantee the safety of occupants and ensure that the plan complies with current standards.
Ventilation et qualité de l’air : plus qu’une obligation
Another often overlooked aspect is ventilation. The Code requires a mechanical ventilation system that allows for sufficient air exchange. This includes the proper placement of exhaust vents, proper distances between air inlets and outlets, and a flow rate consistent with the size of the building.
Furthermore, the prevention of radon—a naturally occurring radioactive gas that can seep into foundations—is becoming mandatory in several regions. The Code now requires the installation of a passive exhaust stack in all new construction. This is a detail that many overlook due to lack of information, but it can have significant implications for the health of occupants.
Structural calculations: beware of shortcuts
In many small building projects, owners or contractors tend to use templates or "copy" dimensions from other similar constructions. However, each site, each structure, and each roof type has its own unique characteristics. Snow loads, winds, soil characteristics, and the configuration of openings all influence the dimensions of beams, joists, load-bearing walls, and foundations.
Ignoring these calculations or relying on rules of thumb can create serious stability, deformation, or even safety issues. The plans created by Plan Maison Québec take these variables into account to avoid any risk of non-compliance or poor workmanship.
Coordination between stakeholders: key to a compliant project
An often overlooked aspect of small projects is the lack of coordination between the various professionals. The architect, engineer, ventilation specialist, and contractor must all work from consistent plans. When everyone works in isolation, errors often occur at the interface: openings don't match, walls aren't properly insulated, ventilation ducts are poorly positioned, and so on.
By working with Plan Maison Québec, you benefit from an integrated approach, where all technical aspects are considered together, rather than in isolation. This significantly reduces the risk of conflict, rework, or cost overruns.
Intermediate checks and inspections
In large projects, inspections are numerous and mandatory. But in smaller residential projects, they are often absent or reduced to a bare minimum. However, many errors can be corrected early if an inspection is scheduled before the walls are closed, before the insulation is installed, or during the installation of mechanical systems.
It is strongly recommended to plan these checkpoints with a professional, even in a residential project. Plan Maison Québec can help you establish a logical sequence of checks to avoid unpleasant surprises at the end of the project.
Why are these oversights so frequent?
Small projects often give the impression that everything can be improvised or simplified. This approach unfortunately leads to the neglect of important elements of the Code. The lack of supervision, detailed plans, or technical validation leaves room for errors that can be costly to correct.
Furthermore, budgetary pressures push some to cut corners on critical items, such as airtightness, structural engineering, or ventilation. The result? A building that appears compliant on the surface, but fails to meet legal requirements, with all the risks that this entails.
Conclusion: National Building Code
Whether your project is small or ambitious, every detail counts when it comes to complying with the National Building Code. Too many homeowners realize too late that an oversight in insulation, a ventilation error, or a failure to comply with structural standards can
result in additional costs, delays, or even penalties.
At Plan Maison Québec, our mission is to offer you comprehensive plans, meticulously designed and in full compliance with current provincial and federal standards. Our team ensures that every technical aspect is integrated into your house, cottage, or garage plan—without compromising on quality, safety, or performance.
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