Roof access stairs. Galvanized exterior steel stairs to rooftop platforms.
When a building gets new HVAC equipment, a service mezzanine on the roof, or a code review that flags inadequate roof egress, the answer is usually an exterior galvanized stair attached to the wall. Same engineering bench as our fire-escape work, sized to the rooftop application.
Service access, egress, or both.
Most roof-access stair projects we see are mechanical-driven — adding an RTU, replacing a unit on a roof platform, or running new conduit and a service route. A smaller share are code-driven: a roof addition that triggers an egress review under OBC §3.4. Both share the same structural and finish requirements; the egress version inherits the egress width and load rules in addition.
Common drivers
- New rooftop unit / replacement — service access for HVAC, refrigeration, or air-handling units.
- Rooftop service mezzanine — elevated equipment platforms with their own egress requirement.
- Code-driven roof egress — buildings without compliant interior roof access.
- PV / solar service — exterior maintenance access for rooftop arrays.
Tread & finish
Bar-grate by default — snow and meltwater shed through the openings, ice does not pond. Hot-dip galvanized to CSA G164 for the steel; powder-coat over galv if architectural review requires colour. The same logic that drives outdoor steel stairs applies.
Anchor design
Roof-access stairs typically attach to an exterior wall. We do a pre-attachment review of the wall composition — masonry coursing, concrete edge condition, or exposed steel framing — and design the anchor pattern as part of the stamp, exactly like a fire-escape retrofit. Anchor counts and sizes go on the drawing alongside the stair geometry.
Typical parameters
- Rise rangetypically 15 ft – 30 ft (single building level to roof)
- Configurationswitchback (most common) / straight-run if room permits
- Treadbar-grate (default for snow / water shed)
- Guard height42" (OBC §3.3.1.18)
- Top platformwalk-out platform with toe-plate at parapet
- Finishhot-dip galvanized, CSA G164
- Service lifemulti-decade galv on inland-Ontario sites (exposure-dependent per AGA chart)
- Lead time4 – 7 weeks from sign-off
- All steel stairs & industrial stair systems
- Outdoor steel stairs — same finish defaults, broader use cases
- Fire escape stairs — same anchor approach, egress-driven
- Cage ladders — when a stair won't fit