In Alberta, a walking surface needs a guard wherever it sits more than 600 mm (2 ft) above the surface beside it, checked out to 1.2 m (3 ft 11 in) away, and that guard must be at least 900 mm (2 ft 11 in) high inside a home and 1 070 mm (3 ft 6 in) in most other places (NBC(AE) 2023, 9.8.8.1 and 9.8.8.3). Its openings must stop a 100 mm (3.9 in) ball. These rules come from the second printing of the National Building Code, 2023 Alberta Edition, in force since 17 August 2026 (Government of Alberta, 2026).
Key takeaways
- As of October 2026, Alberta requires a guard on any open side where the drop is more than 600 mm (2 ft) between the walking surface and the surface within 1.2 m (3 ft 11 in) of it (NBC(AE) 2023, 9.8.8.1).
- Guards inside a home, and outside a home where the floor is no more than 1 800 mm (5 ft 11 in) above the ground, must be at least 900 mm (2 ft 11 in) high; every other guard needs 1 070 mm (3 ft 6 in) (NBC(AE) 2023, 9.8.8.3).
- Openings in a required guard must stop a 100 mm (3.9 in) sphere, and the triangle between a stair tread, riser and bottom rail must stop a 150 mm (5.9 in) sphere (NBC(AE) 2023, 9.8.8.5).
- Where a guard protects a drop of more than 4.2 m (13 ft 9 in), nothing between 140 mm (5.5 in) and 900 mm (2 ft 11 in) above the floor may make it easier to climb (NBC(AE) 2023, 9.8.8.6).
- A guard in a home must take 0.5 kN/m along its top or a 1.0 kN point load, and a load on the infill spread over 300 mm (11.8 in) so it engages three balusters (NBC(AE) 2023, Table 9.8.8.2 and 9.8.8.2).
When does Alberta require a guard?
You need a guard on every open side of a surface people can walk on where the drop is more than 600 mm (2 ft). The code doesn't only look at the ground right at the edge. It compares the walking surface with the adjacent surface anywhere within 1.2 m (3 ft 11 in) (NBC(AE) 2023, 9.8.8.1). A wall that closes off the side does the same job, so a guard is only needed where there's no wall.
The rule names stairs, ramps, outside landings, porches, balconies, mezzanines, galleries and raised walkways. It doesn't apply at loading docks, at pits in repair garages, at places reached only for maintenance, or at the top edge of a flight of stairs.
The code's explanatory note gives the reason for the 1.2 m reach. Builders sometimes pile up soil next to a deck or stair to stay under the trigger, and the note says that "provides little or no protection" (NBC(AE) 2023, Note A-9.8.8.1). Notes explain intent; they aren't requirements. On a sloping lot, one stair can need a guard on its lower half and none at the top.
Doors and windows have their own version of this rule. A door in a home where the floor is more than 600 mm above the ground outside needs a guard or a stop that holds it to a 100 mm (3.9 in) opening, and low windows on upper floors need protection too. The window fall protection guide covers both.
How high does a guard need to be in a house?
At least 900 mm (2 ft 11 in) anywhere inside a home, including the shared stairs and halls of a house with a secondary suite, and 1 070 mm (3 ft 6 in) everywhere the lower figure doesn't apply (NBC(AE) 2023, 9.8.8.3). Outside, a guard serving one home or one house with a suite can stay at 900 mm while the floor it protects is no more than 1 800 mm (5 ft 11 in) above finished ground. Above that, it goes to 1 070 mm.
Here is the minimum height for the places a house usually needs one, as of October 2026:
| Where the guard is | Minimum height | Clause |
|---|---|---|
| Edge of a loft or an open-to-below hallway, inside a home | 900 mm (2 ft 11 in) | 9.8.8.3.(2) |
| Open side of a stair inside a home, measured from the nosing line | 900 mm (2 ft 11 in) | 9.8.8.3.(2) and (4) |
| Shared stair or landing in a house with a secondary suite | 900 mm (2 ft 11 in) | 9.8.8.3.(2) |
| Deck, porch or balcony of one home, floor up to 1 800 mm (5 ft 11 in) above ground | 900 mm (2 ft 11 in) | 9.8.8.3.(3) |
| The same deck, floor more than 1 800 mm above ground | 1 070 mm (3 ft 6 in) | 9.8.8.3.(1) |
| Anything outside a dwelling, such as an apartment corridor or a shop mezzanine | 1 070 mm (3 ft 6 in) | 9.8.8.3.(1) |
Note: code minimums for guards, not recommended heights. The City of Calgary checks them at plan review and inspection.
The code's note says guard heights track the waist height of an average adult, and homes get the lower figure because the people living there learn its hazards and crowds are unlikely (NBC(AE) 2023, Note A-9.8.8.3).
On an open stair, the guard and the handrail are separate rules. The handrail must sit 865 mm to 1 070 mm (2 ft 10 in to 3 ft 6 in) above the nosings and be graspable along its length (NBC(AE) 2023, 9.8.7.4 and 9.8.7.5). A top rail between 900 mm and 1 070 mm falls inside both height ranges. The stair guide has the rest of the stair rules.
How far apart can balusters be?
Close enough that a 100 mm (3.9 in) sphere can't pass through any opening in a required guard (NBC(AE) 2023, 9.8.8.5). That gap has to hold under load too: push two neighbouring balusters apart with 0.1 kN and the opening must still stop the sphere (NBC(AE) 2023, 9.8.8.2.(2)).
These are the opening rules for guards in a home, as of October 2026:
| Opening | Rule | Clause |
|---|---|---|
| Any opening in a required guard | Stops a 100 mm (3.9 in) sphere | 9.8.8.5.(1) |
| Triangle between a stair tread, its riser and the guard's bottom rail | Stops a 150 mm (5.9 in) sphere | 9.8.8.5.(2) |
| A guard nobody required, where the drop is 600 mm (2 ft) or less | Stops a 100 mm sphere, or lets a 200 mm (7.9 in) sphere through | 9.8.8.5.(4) |
| Two balusters pushed apart with 0.1 kN | Still stops the 100 mm sphere | 9.8.8.2.(2) |
Note: these apply to residential guards; industrial guards have looser rules not shown here.
The middle band is banned on purpose. A gap between 100 mm and 200 mm is wide enough for a child's body and narrow enough to trap the head, the code's note explains (NBC(AE) 2023, Note A-9.8.8.5.(4)). So a decorative rail on a low step-down must be either tight or wide open.
Can a guard have horizontal rails or cables?
The code only bans climbable guards where the drop is more than 4.2 m (13 ft 9 in). Above that height, no member, attachment or opening between 140 mm (5.5 in) and 900 mm (2 ft 11 in) above the floor may help someone climb (NBC(AE) 2023, 9.8.8.6). In a house, that height shows up at a loft edge over a two-storey living room or a walkout deck above a steep yard. Below 4.2 m, the code text sets no climbing rule, though the 100 mm sphere still applies to cable and rail spacing.
The note gives examples that don't count as climbable: footholds more than 450 mm (1 ft 6 in) apart both ways, ledges that stick out 15 mm or less, and slots no bigger than 45 mm by 20 mm (NBC(AE) 2023, Note A-9.8.8.6.(1)). That's guidance on meeting the rule, not a rule of its own.
The drawing shows a 1 200 mm (3 ft 11 in) length of guard at the 1 070 mm height, with the 900 mm line that applies inside a home and the 140 mm to 900 mm zone that must stay unclimbable above a 4.2 m drop.
Calgary's own deck paperwork goes a step further. The City's uncovered deck checklist, updated August 2026, draws the same 36 in and 42 in heights and a 4 in maximum opening, and its sample section notes that no part of the railing should be climbable, with no height condition (The City of Calgary, deck checklist 2026). If you want horizontal rails on a deck, ask the City how it reads that note before you order them.
How strong does a guard have to be?
A guard inside a home, or outside one serving no more than two homes, must resist 0.5 kN/m along its top or a 1.0 kN load at any point, whichever is worse. The infill must take 0.5 kN over an area up to 300 mm (11.8 in) square, and the top 1.5 kN/m pressing down (NBC(AE) 2023, Table 9.8.8.2). Guards elsewhere take 0.75 kN/m at the top.
In a home, where balusters are spaced so that three fit in a 300 mm width, the infill load is applied across all three (NBC(AE) 2023, 9.8.8.2.(3)). For homes, the table can also be set aside for a guard design that has been shown to perform. The note points to the guard examples in Supplementary Standard SB-7 of the 2012 Building Code Compendium as constructions that meet the loads (NBC(AE) 2023, Note A-9.8.8.2).
Glass in a guard must be tempered or laminated safety glass, or wired glass (NBC(AE) 2023, 9.8.8.7). On a Calgary deck, a frameless glass railing also needs an engineer's design with the permit application, according to the City's checklist. The deck code guide covers the rest of a deck.
What does a walkthrough show about guards?
A full-size walk shows where your open edges are. On the LED floor, you can stand at the edge of a loft, an open stair or a deck and see how much of it is open, which tells you how many metres of guard the plan needs. The elevations go up on the wall-size screen behind the floor, so the guard height sits next to the room it protects, and changes are made on the spot.
Every session is recorded and you keep the recording. Sessions are quoted for your plan, with nothing to pay at booking (see how quotes work). Read the other building code guides, see how walkthroughs fit renovations, or book a session.
Questions
How high does a railing have to be in Alberta?
In Alberta, a guard (the railing at an open edge) must be at least 900 mm (2 ft 11 in) high inside a home, as of October 2026. Outside, a home's deck or porch can keep a 900 mm guard while its floor is no more than 1 800 mm (5 ft 11 in) above the ground; higher than that, and anywhere outside a dwelling, the guard must be 1 070 mm (3 ft 6 in).
When is a guard required in Alberta?
Alberta requires a guard where a walking surface is more than 600 mm (2 ft) above the surface next to it, measured anywhere within 1.2 m (3 ft 11 in). A wall along that side removes the need for a guard.
What is the maximum baluster spacing in Alberta?
In Alberta, the openings in a required guard must be small enough to stop a 100 mm (3.9 in) sphere, which in practice means balusters less than 100 mm apart. The triangle at the bottom of a stair guard can be a little bigger: it must stop a 150 mm (5.9 in) sphere.
Are horizontal railings allowed in Alberta?
Alberta's building code only bans climbable guards where the drop is more than 4.2 m (13 ft 9 in), and then only between 140 mm and 900 mm above the floor. Calgary's deck checklist adds a note that no part of a deck railing should be climbable, so check with the City before you build a horizontal deck rail.
Does a basement suite change the guard height?
No: a house with a secondary suite gets the same 900 mm (2 ft 11 in) minimum as any home, inside each unit and on the shared stairs and halls. The 1 070 mm (3 ft 6 in) height applies outside, where the floor is more than 1 800 mm above the ground.
Sources
- NBC(AE) 2023, 9.8.8.1 and 9.8.8.3 nrc-publications.canada.ca
- Government of Alberta, 2026 alberta.ca
- The City of Calgary, deck checklist 2026 calgary.ca
