A concrete staircase is a structural element with a very tight dimensional standard applied to it — the going, rise and headroom are all controlled by Building Regulations Part K, on top of the reinforcement and formwork requirements any concrete pour carries. A specification that only describes the finish (polished, floating, cantilevered) without addressing structure and compliance geometry is incomplete.
Going, rise and headroom
The spec should state the exact going and rise for each step, calculated to comply with Building Regulations Part K for the stair's use (private stair rules differ from common stair rules in flats), along with the headroom clearance above the pitch line. These figures need to be fixed before formwork is built, because concrete stairs can't be adjusted once struck the way a timber stair can be trimmed.
Handrail height and any requirement for handrails on both sides, or balustrade design where the stair is open-sided, should also be specified against the regulations rather than left to look right on site.
Reinforcement and structural design
For an in-situ concrete stair, particularly a cantilevered or floating design, the spec should reference the structural engineer's reinforcement drawing showing bar sizes, spacing and the support or fixing detail into the surrounding structure. Cantilevered treads carry their full load through the fixed end back into the supporting wall or stringer, and this connection detail is the single most safety-critical part of the design.
Where a helical or curved stair is specified, the reinforcement detailing becomes more complex still, and the spec should confirm this has been engineered specifically for the geometry, not adapted from a standard straight-flight design.
Formwork and finish tolerance
The formwork for a stair needs a tighter tolerance than most other concrete elements because uneven risers are both a trip hazard and highly visible. The spec should state the tolerance being worked to for step uniformity, and the finish specification — power-floated, polished, board-marked, or ground — since each requires a different formwork lining and finishing process after striking.
Precast versus in-situ
Where a precast concrete staircase is being supplied rather than poured in-situ, the spec should state the manufacturer, the lifting and installation method, and the connection detail into the surrounding structure at top and bottom landings, since a poorly detailed connection is a common source of movement or cracking after installation.
What a vague concrete staircase quote tends to omit
Structural engineer's design fee for the stair itself (as distinct from the rest of the building), an allowance for the finish and sealing treatment, and the cost of temporary edge protection and safe access during construction are common gaps.
- Structural engineer's reinforcement design specific to the stair
- Going, rise and headroom confirmed against Part K
- Formwork tolerance and finish specification stated together
- Balustrade and handrail specification against the regulations
- Temporary edge protection during construction
Common questions
Why is going and rise so tightly regulated on a staircase?+
Uneven or excessive rise-to-going ratios are a leading cause of trips and falls on stairs, so Building Regulations Part K sets specific limits for private and common stairs to reduce that risk.
Does a cantilevered concrete staircase need special engineering?+
Yes — the whole load of each tread is carried through its fixed end back into the wall, so the reinforcement and the wall's ability to take that load both need to be specifically calculated by a structural engineer.
Can a concrete staircase be adjusted after it's cast if the rise is wrong?+
Not realistically — correcting geometry after striking usually means breaking out and recasting the affected section, which is why the dimensions need to be right before the pour, not checked afterwards.
Get a concrete staircase specification with structure and geometry confirmed
We work the going, rise and reinforcement design out with a structural engineer before any formwork is built.