The Alberta Building Code (ABC), through direct adoption of the National Building Code of Canada (NBC), mandates exacting dimensional requirements for landings at the top of interior flights of stairs. The minimum size and geometry of these landings, especially in multifamily and mixed-use projects, have critical implications for safety, code compliance, and long-term usability. Key NBC criteria inform the design and construction practices across Alberta, and even minor deviations during value engineering or field changes can result in non-compliance, requiring costly retrofits or delays at occupancy.

Definition and Function of the Top Landing

A landing is not simply a pause in a path; it is an engineered safety device and a code-mandated transition zone. At the top of a flight of interior stairs, a landing must allow for:

  • Safe stopping - An occupant must be able to reach the top, stop, and change direction (or prepare to access adjacent rooms or corridors) without risk of over-stepping or crowding on a constricted tread.
  • Resting and transitioning - Especially for the elderly or individuals carrying loads, the landing provides a moment to recover and assess the next movement, crucial in multifamily buildings with high occupant diversity.
  • Accessibility compliance - Landings accommodate users with mobility aids by providing the needed space for turning and maneuvering, supporting wider universal design goals and eliminating barriers.
  • Architectural integration - The landing frequently serves as a junction for circulation or a point of change in direction (such as an L-shaped or U-shaped stair). Its dimensions anchor stair design in the larger spatial order of the floor plate.

Dimensional Requirements: NBC 9.8.6.3.(1) in Detail

According to NBC 9.8.6.3.(1), adopted without substantive amendment by the ABC, the minimum size for a landing at the top of an interior flight of stairs is governed by the stairway’s width. Two rules define the landing’s plan dimensions:

  • Width: The landing must be at least as wide as the stairway it serves. The width of the stairway is measured between finish surfaces of walls or guards, not stringers. For a 900 mm stair, the landing must be at least 900 mm wide clear of obstructions aside from permissible handrails.
  • Length (depth) in the direction of travel: The length of the landing, measured perpendicular to the stair nosing and parallel to the intended path of travel, must also be at least equal to the stairway width. Thus, for a 900 mm wide stair, a minimum 900 mm landing (in the direction of travel) is required.

Most designs infer a square landing profile; however, the essential requirement is that both landing dimensions measured perpendicularly (width and depth) are not less than the stair width immediately below.

Illustrative Calculation and Impact on Design

Suppose a residential project specifies a 950 mm wide interior stair. The code requires the top landing, measured from the first riser to any terminating obstacle (e.g., wall, door, or open edge guard), to be a minimum of 950 mm in width and 950 mm in the direction of travel. A landing of 900 mm by 950 mm (width by depth) would not comply-even if the width meets the rule, the depth would be insufficient, exposing designers and builders to inspection failure or retrofit orders.

Implications for Layout and Space Planning

Minimum landing sizes often challenge architectural and engineering teams, especially on tight infill footprints, midrise developments, and podium/tower mixed-use blocks where gross floor area must be maximized while meeting code. Some of the most common real-world challenges include:

  • Configuration of suite entries adjacent to stairs - Ensuring sufficient clear landing beyond outward-swinging doors and providing code-compliant egress zones at main corridor junctions, even under tight corridor widths or angled wall conditions.
  • Stair offset due to service runs or mechanical chases - Achieving the full required landing without encroachment from HVAC or plumbing drops, which can discreetly reduce usable area and must be accounted for in both design and prefabrication.
  • Non-orthogonal layouts - Landings configured within cranked, curved, or skewed walls still require a minimum rectangular zone, not a reduced “measured on the diagonal” footprint.
  • Interaction with elevator shaftways or refuge areas - Especially in larger multifamily work, landing size must be preserved in the context of exit stair integration with fire-rated lobbies or smoke-proof enclosures. Here, deviation from the minimum landing size can impact compliance with multiple code sections simultaneously.

Early coordination between architectural planning and structural design is critical. Foundation wall steps, floor truss drops, or mechanical distribution cannot infringe on the landing zone; a loss of even 25-50 mm in landing depth can render an otherwise code-conforming stair noncompliant.

Exceptions: Doors Swinging Away from Stairs

The NBC recognizes that not all stair-to-level transitions require a built landing. The most relevant exception appears in NBC 9.8.6.2.(2):

  • If a doorway is located at the top of an interior flight within a dwelling unit (such as a suite entry, in-suite stair, or townhouse vertical circulation), and the door swings away from the stair toward the level floor, code does not require a landing between the door and the first riser. The logic is that when the door is opened, all floor area revealed on the level side provides sufficient space for safe entry or exit, and there is no hazard of being forced backward down the stair by the door leaf.

This exception streamlines planning in interior stacked townhouses or multi-level suites where net floor area is at a premium. By flipping a door swing to open away from the stair, designers may recapture valuable space otherwise devoted to a landing. However, this must be balanced with accessibility and operational requirements, particularly in layouts where door swing might interfere with traffic patterns or accessibility turn circles in adjacent rooms or corridors.

Any reversal from the out-swing configuration-whether for architectural, furniture, or hardware preferences-nullifies the exception, and the landing must be immediately reinstated to full code-minimum dimensions.

Exterior Landings: Relevance and Limits of Exceptions

While the main thrust of this discussion is interior top landings, many developments-especially row housing, six-plexes, or walk-up apartments-feature stair connections to exterior doors. NBC 9.8.6.2.(3) provides an exception applicable only to exterior stairs at secondary entrances:

  • If the exterior stair serves a secondary entrance to a single dwelling unit (not a primary egress), a landing at the top of the stair may be omitted if:
    • The stair has no more than three risers.
    • The principal door is a sliding door or swings away from the stair.
    • If there is a storm or screen door, it swings over the stair and is equipped with a device to hold the door open.

This exception recognizes the practicalities of tight site development, particularly for secondary entrances (such as rear-yard access or deck stairs) where incorporating a full-size landing would be disproportionately intrusive or create a code-minimum feature used infrequently. However, for interior stairs, no such exception exists: full-compliance landings are required at all level-to-stair transitions, save for the door swing provision outlined above.

Material, Performance, and Detailing Considerations

Meeting dimensional minimums is merely the first requirement; the construction of a top landing must also satisfy performance and longevity criteria:

  • Finish and traction - Landings are subject to frequent foot traffic and must provide a slip-resistant surface, especially in Alberta’s climate with frequent carry-over of snow and grit. For multifamily, high-rise, or commercial-intensity traffic, slip coefficients exceeding code minimum may be considered. Materials selection, from resilient vinyl to porcelain tile or sealed wood, should anticipate both load and maintenance requirements.
  • Structural loads - Landings must be designed to the same load-bearing criteria as adjacent stair flights, including live loads stipulated in Table 4.1.5.3. of the NBC/ABC. In podium construction, topping slabs, steel stair pans, or pre-cast elements need adequate bearing, anchorage, and finish overbuild to ensure full code compliance.
  • Tolerances and field execution - Once rough carpentry or concrete has established actual framing or formwork, any deviation from plan-creep in wall finish, misaligned stringers, or thicker than expected underlay-can subtly erode the clear landing dimensions. Routine field checks and explicit layout marking during construction can avoid last-minute remedial chipping or reframing, which is especially complex in fully sprinklered or fire-rated envelopes.
  • Integration with guards and handrails - Guards and handrails must not infringe upon the minimum landing width, and handrail returns at the top of a stair must terminate clear of the primary circulation path unless specifically permitted by code exceptions. Coordination between finish trades is essential.
  • Transitions to other finishes - At the top landing, transitions to corridor finishes, door thresholds, or expansion joints require careful control of level, gap, and trip hazard, with each edge detailed to avoid creating a new hazard in the effort to address the old.

Special Configurations and Common Pitfalls

Certain architectural layouts and renovation scenarios present recurring challenges:

  • Dogleg, winder, and switchback stairs - U-shaped or L-shaped stairs with intermediate landings must have each landing sized by the code minimum, regardless of the stair’s intended width changes. Inconsistency between lower and upper flights, particularly where stairs overlap structurally, can result in pinch points or sub-code landings at turns.
  • Encroachments above landings - Vertical clearance along the entire exit path, including landings, must comply with the required headroom minimum, and no building service, dropped bulkhead, or decorative soffit should reduce usable height or limit maneuverability. Close review is necessary in renovation and basement finishing contexts where existing beams or plumbing drops may crowd the landing zone.
  • Staggered suite entryways - In multifamily or stacked townhouse applications, housing units accessed via alternating-level landings may not provide sufficient pause space between the stair flight, the door swing, and any service or mechanical closets. Rigorous layout checks are vital before approving such schemes.
  • Permitting of value-engineered or modular stairs - Modular or repeat stair assemblies, or substitution of engineered stair-and-landing units during value engineering, can result in field-installed elements with landing dimensions just shy of code minimums, especially when cumulative tolerances are not accounted for. Formal shop drawing approval and dimensioned submittals are essential parts of compliance.

Inspection and Enforcement in Alberta

Building officials in Alberta routinely cite landing size deficiencies as work order items during rough and final inspections. Observed issues often include:

  • Landing depth measured from nosing to wall failing to meet required stair width, often by marginal amounts (5-20 mm).
  • Obstructions on the landing-such as guard posts, radiator units, or entry shelves-reducing clear width below code minimums.
  • Entries where in-swing doors encroach on the landing travel path, invalidating the door swing exception and triggering the full landing requirement retroactively.

Remedial action typically involves costly and time-intensive rework: moving risers, reframing platforms, or relocating doors and walls. In multifamily settings, these changes can trigger a cascade of knock-on effects including adjusted corridor lines, revised mechanical penetrations, and updates to fire-stopping and ratings, frequently delaying occupancy or triggering partial re-inspections. Proactive, code-based stair and landing layouts, coordinated from schematic through IFC (Issued for Construction) and rigorously enforced in sub-trade scopes, are the most reliable means of avoiding such risk.

Linking Code Minimums to Occupant Safety and Building Performance

The regulatory minimum for top landings is not an arbitrary box-ticking exercise. Landings sized to stair width are integral to occupant safety in both routine use and in egress scenarios when stairs are crowded or used in low-light or smoke conditions. Adequate landing area allows occupants to:

  • Pause, re-orient, and assess direction in unfamiliar buildings or during emergency evacuation;
  • Facilitate passage for persons using mobility aids including walkers, crutches, or strollers;
  • Safely negotiate turns (especially on dogleg stairs) without crowding or forcing users backward over open stair risers;
  • Accommodate bidirectional traffic, improving emergency egress times and reducing stair congestion in larger, multi-unit buildings.

Alberta’s adoption of NBC 9.8.6.3.(1) as the standard recognizes that squeezing landings, either in the direction of travel or width, increases both risk and liability, particularly in barrier-free or age-in-place community designs, which are increasingly the norm in new multifamily housing.

Landings in the Context of Universal Design and Accessibility

Strict adherence to minimum landing dimensions is foundational for barrier-free design. While NBC minimums are absolute, recommendations for stairs serving barrier-free paths (e.g., those adjacent to accessible units or shared public amenities) often exceed code minimums to allow for full turning radii (e.g., 1500 mm x 1500 mm for wheelchairs) or extended passing zones. Alberta’s multifamily and affordable housing policies are beginning to reward proactive design that exceeds minimum code provisions, which can position projects for funding or expedited approval in some jurisdictions.

Additionally, surface transitions at landings, nosing differentiation, and tactile warning strips can support visually impaired users. Precise planning of handrail extensions-termination before, at, or beyond the landing-based on user needs and code requirement, is essential for achieving best-in-class outcome while preserving code compliance.

Preconstruction: Laying the Groundwork for Code-Compliant Landings

Optimal integration of the NBC’s landing minimums into construction documents starts at preliminary planning. Techniques include:

  • Creating redline overlays in design development showing clear dimensions-wall-to-wall, nosing-to-wall-for all landings, not just “typical” conditions.
  • Mandating dimensioned shop drawings from stair subcontractors and reviewing for code compliance as a permit or tender submittal requirement.
  • Requiring BIM/CAD clash detection for all stair-landings adjacent to structural, MEP, and fire-rated construction to ensure no as-built conflicts reduce the eventual code-conforming clear area.
  • Setting out explicit finish build-ups in the architectural specifications and highlighting any variance in underlayment or finish that might encroach on the landing’s code-mandated clear zone.

Such diligence shortens the punch-list and insulates projects from post-framing surprises, reduces rework, and accelerates final occupancy certifications.

Field Practices: Execution, Verification, and Documentation

Site execution of stair and landing assemblies depends on robust layout controls and methodical measurement. Best practices include:

  • Use of physical templates or marked subflooring indicating “no encroachment” landing zones before stair stringers or finish walls are placed.
  • Third-party surveying to verify that as-built landings match plan and code minimums prior to sign-off by building inspectors.
  • Inclusion of photographic or as-built dimension logs in project closeout documentation, providing a compliance record should future renovation, warranty, or incident assessment be required.
  • Explicit trade scopes outlining that no handrail, baseboard, mechanical casework, or post base may reduce the clear width or depth of the top landing below the stair width minimum set out in NBC 9.8.6.3.(1).

Clear communication of these requirements during pre-construction meetings, regular on-site verifications, and post-construction walk-throughs with both quality control and safety personnel reduces the risk of oversight at each project milestone.

Risks of Non-Compliance: Cost, Timeline, and Reputation

Omitting or undersizing a required landing exposes projects to severe downstream consequences:

  • Enforcement action: Non-compliance leads to withheld occupancy permits or requirement for costly site modifications, often in already finished interiors.
  • Safety liability: Inadequate landings are a common factor in trip, slip, and fall claims, especially involving children or seniors, with documented non-compliance carrying liability multipliers for insurers and in civil courts.
  • Project timeline impact: Achieving sign-off on fire and life safety in multifamily projects is contingent on inspection of egress paths, with deficient landings frequently becoming the pace-setter for final acceptance.
  • Brand reputation: Recurring code deficiencies compromise the credibility of project teams and can limit future work with institutional, affordable housing, or public-sector clients who maintain code-compliance records.

Opportunities in Exceeding Code: Market and Tenant Benefits

In Alberta’s growing market for multigenerational and accessible housing stock, building to code minimum should be considered the baseline, not the benchmark. Developers opting to increase landing dimensions-such as providing consistent 1050-1200 mm landings regardless of stair width, using contrasting nosings, or integrating landings with wider circulation zones-may elevate both the perceived and actual value of their product.

Such improvements can accommodate diverse tenant needs, meet or exceed accessibility funding requirements, and future-proof buildings for evolving code regimes and demographic trends. Enhanced landings, when coordinated with high-traction and resilient finishes, also reduce ongoing maintenance and risk, an appealing proposition for investment metrics focused on lifecycle costs and tenant retention.

Summary of Key Mandates

  • For interior stairs in all buildings overseen by the ABC, the top landing must be at least as wide as the stair and at least as long (in the direction of travel) as the stair width-no exceptions except the specific door swing condition.
  • Main exceptions only apply where an interior door at the top of stairs swings away from the stair; the opening floor area then serves as the code landing.
  • Landing requirements are rigorously enforced and integral to routine and emergency stair use, with direct implications for both safety and code-based liability.
  • Designers and builders should exceed code minimums wherever possible, aligning with best practices in accessibility, safety, and long-term operational efficiency.

Conclusion

The dimensions and design of top landings at interior flights of stairs, as prescribed by NBC 9.8.6.3.(1) and enforced via the Alberta Building Code, are among the most consequential details in multifamily and mixed-use construction. Code-compliant, robustly documented landing layouts not only satisfy minimum safety requirements but also enhance accessibility, durability, and asset value. Proactive collaboration between architecture, engineering, construction management, and field trades is essential from pre-design through to occupancy, ensuring that minimum and recommended standards for stair landings translate into reliable, livable, and market-competitive Alberta buildings.

Kingsway Builders delivers code-focused execution and advanced multifamily project delivery throughout Calgary and Alberta.