Open vs Closed Riser External Stairs in Queensland

Open or closed risers? It's the most-asked design question on every external timber stair quote in Brisbane. Each has real advantages in our subtropical climate, and the right answer depends on your home's age, exposure and the look you want.

What Open and Closed Risers Mean

The riser is the vertical face between two consecutive treads. A closed riser has a timber board filling that gap — the classic enclosed look. An open riser leaves the gap empty so you can see straight through the stair.

Open Riser — Pros & Cons

Pros:

• Excellent airflow — treads dry rapidly after rain, reducing rot risk.
• Contemporary, lighter visual feel.
• Cheaper to fabricate (8-15% less than closed).
• Easier to clean leaf litter and debris from underneath.
• Pairs well with steel stringers for modern designs.

Cons:

• Some people find them visually unsettling, especially at height.
• Drops anything you spill onto whatever is below.
• Stringer detailing must be flawless because it is fully exposed.

Closed Riser — Pros & Cons

Pros:

• Traditional, solid look — essential for Queenslander restorations.
• Hides the under-stair space (storage, lattice screening, services).
• Slightly stiffer feel underfoot.
• Safer perception for young children and elderly residents.

Cons:

• More timber components — adds 8-15% to cost.
• Requires careful drainage detailing in external use.
• Slower to dry after rain; needs more diligent oiling.

NCC 2022 — The 125mm Gap Rule

The big compliance point for open-riser external stairs: the gap between consecutive treads must not exceed 125mm — the same rule that applies to balustrade infill. A 180mm riser height typically gives a 70-90mm open gap after subtracting the tread thickness, which sits well inside the limit.

See our plain-English NCC 2022 stair compliance guide for the rest of the geometry rules.

Which Suits the SEQ Climate?

Open risers are the natural fit for our humid subtropical climate. Airflow is a hardwood stair's best friend, and an open-riser stair dries in roughly half the time of a closed equivalent after a Brisbane summer downpour. That said, well-detailed closed risers with drainage gaps perform very well too — and on a heritage Queenslander, the traditional closed look is worth the small extra maintenance.

Our Recommendations by Home Style

• Contemporary new build: Open riser, hardwood treads on steel mono-stringer.
• Queenslander restoration: Closed riser, painted stringer, oiled treads. See our Queenslander external stairs guide.
• Coastal Sunshine Coast home: Open riser in Ironbark — best airflow + best durability for salt air.
• Family home with small children: Closed riser for the perceived safety, or open riser with a 100mm maximum gap.

For the full design + costing context see our pillar guide to external timber stairs across SEQ, our hardwood species comparison, or our 2026 cost guide. Call Craftsman Stairs on 0439 730 583. QBCC 69007 · ABN 86 475 603 796 · since 1989.