Accessibility: NBC Section 3.8 and CSA B651

Daniel Achterberg, the accessibility consultant who reviewed the community hub in Design Studio III, arrives at the school ten minutes early and waits outside the classroom. When the class gathers, he explains why. 'The accessible entrance to this building is around the back, past the loading dock, and the power door opener has not worked since September. The elevator to this floor is at the far end of the building. It took me twenty minutes from the bus stop to this room, and you took four. The building meets the code that was in force when it was built. It is still a building that tells me I am an afterthought.' He uses a power wheelchair and has worked on accessibility for twenty years. 'The code is the minimum. Today I want you to learn the minimum, and then I want you to understand why I am asking for more.'

Who accessibility is for

Accessibility requirements make buildings usable by people with disabilities: people who use wheelchairs, scooters, walkers or canes; people who are blind or have low vision; people who are deaf or hard of hearing; people with limited strength, reach, dexterity or stamina; and people with cognitive and learning disabilities. In both Canada and the United States, roughly one adult in four reports a disability of some kind, and the share rises steeply with age. Many more people have a temporary disability, from a broken leg to the last months of pregnancy, or are travelling with a stroller, a suitcase or a small child. A building that works for a wheelchair user works for all of them.

Achterberg describes two ways of thinking about disability. In the medical model, disability is a problem located in a person's body, to be treated or accommodated as an exception. In the social model, which has shaped modern accessibility law, a person has an impairment, but it is the environment that disables them: the stair without a ramp, the sign too small to read, the alarm with no light. Seen this way, an inaccessible building is a design failure, not a medical fact. The architect Ronald Mace, who used a wheelchair himself, gave the idea a positive name in the 1980s: universal design, the design of products and environments usable by all people, to the greatest extent possible, without the need for adaptation or specialized design.

Accessibility law and standards

Accessibility in Canadian buildings is governed by several layers of law. The National Building Code contains the main technical requirements in Section 3.8, renamed from barrier-free design to accessibility in the 2020 edition. Section 3.8 applies to most buildings other than houses and some industrial and small buildings, and it refers in places to CSA B651, Accessible Design for the Built Environment, the national standard whose current edition was published in 2023. The 2025 National Building Code extends the accessibility objective to all types of dwelling units and allows provinces to decide how the new requirements apply to housing. Provinces and cities may add their own requirements: Manitoba's Accessibility for Manitobans Act of 2013 sets standards for customer service, employment, information and the design of public spaces, and federal buildings and federally regulated organizations are subject to the Accessible Canada Act of 2019. Provincial human rights codes also require providers of services and housing to accommodate people with disabilities, which may require more than the building code does.

Achterberg asks the students to remember one practical rule. Because the different laws and standards overlap and differ in detail, a building must meet all of those that apply to it, which in practice means meeting the strictest requirement for each element. A designer in Manitoba who follows only Section 3.8 may still face a human rights complaint if a service provider's building excludes a person with a disability.

The accessible path

The core of every accessibility standard is the accessible path, a continuous route that people using wheelchairs and other mobility aids can follow from the street or the parking area, through an accessible entrance, to every space they need to use, and back out again. Along the path, the standards control width, slope, cross slope, changes in level, surfaces, door widths and the space needed to approach and open doors, and the provision of spaces to turn around.

Doors are the most common failure on accessible paths. A door that is wide enough can still be impossible to open if there is no space beside the latch for a wheelchair user to pull it, if it is too heavy, if its hardware needs a tight grip or twist, or if it closes too quickly. The NBC requires power door operators at the accessible entrances of many buildings, including assembly, business and mercantile buildings, and at some interior doors. Achterberg notes that the most useful single feature for him is not a ramp but an automatic door that works.

Entrances, washrooms and other spaces

Section 3.8 requires that at least half of a building's pedestrian entrances be accessible, including the main entrance in many cases, and that an accessible path lead from the entrance to every storey that the code requires to be accessible, by elevator, ramp or platform lift. Most floor areas must be accessible, with exceptions for some service spaces and for upper storeys of small buildings. Where washrooms are provided, accessible washrooms or a universal washroom must be provided, with grab bars, a lavatory with knee space and controls within reach. Assembly spaces with fixed seats need wheelchair spaces dispersed through the seating, and large assembly spaces need assistive listening systems for people who are hard of hearing. CSA B651 adds detailed requirements for signage, lighting, visual contrast and tactile walking surface indicators that warn people who are blind of stairs, platform edges and street crossings.

The hub's design passes most of these tests because Callum designed it with Achterberg's help in Design Studio III: every public space is on a level route or reached by elevator, the gallery along the hall slopes at about 1 in 40, gentle enough that it is not a ramp at all, and the main entrance at the glass corner has a power operator. Achterberg still finds work to do. The stage in the hall is reached only by steps, so a performer in a wheelchair cannot get onto it; the code requires an accessible route to stages in many cases, and Callum adds a short ramp at the side. The daycare's child-height sinks are fine for the children, but staff and parents who use wheelchairs need an accessible adult washroom nearby.

Accessible housing

Housing has been the least regulated part of accessibility in Canada. Section 3.8 of the 2020 NBC applies mainly to common areas of apartment buildings, such as entrances, corridors, mail rooms and amenity rooms, and requires few accessible features inside dwelling units, although several provinces, notably British Columbia and Ontario, have added their own requirements for adaptable or accessible units. The 2025 national codes extend the accessibility objective to dwelling units of all types and let provinces choose how far to apply it. Greenway Homes goes beyond the minimum: twelve of its 49 homes are fully accessible, with roll-in showers, lowered counters and wider bedroom doors, and the rest are adaptable, with blocking for grab bars, removable base cabinets under sinks and space to add accessible features later.

The script below checks a ramp, counts the accessible parking and units Greenway Homes needs, and compares them with what Wren has provided.

# Ramp, parking and unit checks for Greenway Homes
rise = 0.62                        # change in level from the parking court to the lobby (m)
slope = 1 / 12
run = rise / slope
landings = int(rise / 0.75 - 1e-9)  # intermediate landings needed with 750 mm maximum rise per run
print(f"ramp: run {run:.2f} m at 1:12 with {landings} intermediate landing(s) plus top and bottom landings of 1.5 m")
print(f"a gentler 1:20 walk would need {rise * 20:.1f} m but no handrails or landings")

homes, accessible_built = 49, 12
print(f"accessible homes provided: {accessible_built} of {homes} ({accessible_built / homes:.0%}); the rest adaptable")
stalls_total, accessible_stalls = 6, 4
print(f"parking: {accessible_stalls} of {stalls_total} stalls accessible (set by the zoning by-law; design to CSA B651)")

ramp: run 7.44 m at 1:12 with 0 intermediate landing(s) plus top and bottom landings of 1.5 m
a gentler 1:20 walk would need 12.4 m but no handrails or landings
accessible homes provided: 12 of 49 (24%); the rest adaptable
parking: 4 of 6 stalls accessible (set by the zoning by-law; design to CSA B651)

The ramp from the parking court rises 620 mm, so it needs a run of about 7.4 m at 1:12, without an intermediate landing because the rise is under 750 mm. Wren prefers to regrade the court so that the walk to the lobby slopes at 1:20 over 12.4 m; at that slope it is not a ramp and needs neither handrails nor landings, and it is pleasanter for everyone. The twelve accessible homes are about a quarter of the total, well beyond the code, and the four accessible stalls in a lot of six reflect Greenway's residents rather than any minimum.

Beyond mobility

Achterberg ends with the disabilities the students had not thought about. A person who is blind navigates by touch, sound and memory: they need consistent layouts, tactile and audible cues at doors and stairs, and signs they can read with their fingers. A person with low vision needs contrast between floors and walls, between stair nosings and treads, and between door frames and walls, and lighting without glare. A person who is deaf needs visible alarms and good sightlines for signing and lip-reading, which is one reason for the glass walls of the hub's meeting rooms. A person with a cognitive disability or dementia needs simple routes, clear landmarks and quiet. A person with environmental sensitivities needs fresh air and materials that do not off-gas. Few of these needs are fully covered by the code, but every one can be met by careful design.

Exercise 9: accessibility

• Trace the accessible path through your Design Studio IV project from the street to every space, and mark every door, change in level and turning space.
• Check the dimensions of one accessible washroom and one accessible dwelling unit against the standard in force, and draw them at 1:20.
• Visit a public building with a person who uses a wheelchair, a cane or a stroller, and record every obstacle you meet together.
• Identify three features in your project that serve people with sensory or cognitive disabilities.

Self-check

• Is the accessible entrance the main entrance, or at least an equal one?
• Have I checked every door for clear width, maneuvering space and hardware?
• Have I thought beyond mobility, to vision, hearing and cognition?