What Is the Ideal Rise and Going on a Bespoke Curved Staircase?

Ask this question on a straight flight and you get a tidy answer: two numbers, applied identically to every step, done. Ask it about something that curves and the tidy answer falls apart almost immediately, because on a tapered step the going is not one measurement at all. It varies continuously across the width. Wide at the outer string, narrow at the inner one, and only correct at whichever position you decide people actually walk.

That decision, not the raw figures, is what separates a flight that feels effortless from one that feels subtly wrong. I've walked plenty of technically compliant staircases that nobody enjoys using, which suggests compliance and comfort are related but far from identical.

So this piece covers what the guidance permits, what we target in practice, and why the walking line matters more than any single number in the drawing.

Quick Answer: The Numbers Worth Starting From

Private domestic guidance in both jurisdictions caps riser height at 220mm and sets the minimum going at 220mm, with pitch limited to 42 degrees. Those are ceilings, not targets.

On a bespoke curved flight we usually aim lower: roughly 175mm to 190mm per step, paired with a going of 260mm to 290mm measured along the walking line. Pitch lands somewhere between 32 and 37 degrees. Comfortable, unhurried, and a long way from the legal maximum.

Where the walking line sits, though, changes everything downstream.

What Building Regulations Permit in Ireland and the UK

Both countries land in a similar place, which simplifies matters for cross-border projects.

Approved Document K, covering England and Wales, allows a maximum riser height of 220mm and a minimum going of 220mm for private stairs, with a pitch no steeper than 42 degrees and the sum of twice the riser plus the going falling between 550mm and 700mm. Ireland's Technical Guidance Document K sets out equivalent provisions (TGD K, gov.ie).

Parameter	Private Domestic Limit	Our Usual Target
Riser height	220mm maximum	175mm to 190mm
Going	220mm minimum	260mm to 290mm on the walking line
Pitch	42 degrees maximum	32 to 37 degrees
Twice the riser plus going	550mm to 700mm	Around 600mm to 640mm
Headroom above the pitch line	2000mm	2100mm where the ceiling allows
Uniformity	Every step identical within a flight	Non-negotiable

Two points people miss. First, those two rise and going extremes cannot be combined: pairing the tallest permitted step with the shallowest permitted depth produces roughly 45 degrees, which breaches the pitch limit outright. The parameters interact, they don't sit on a menu.

Second, uniformity is absolute. Every step in a flight must share the same rise, and building control does check with a gauge. A discrepancy of a few millimetres at the top, usually caused by an unaccounted floor finish, is the single most common reason a beautiful staircase fails inspection.

Why a Curve Changes the Arithmetic

Here is the part that generic advice tends to skip.

On a tapered step, the going depends entirely on where you measure it. Guidance handles this by defining a measuring position: for flights under a metre wide, at the centre of the step; for wider ones, at 270mm in from each side, with both positions needing to satisfy the minimum. There's also a floor at the narrow end, since a sliver of timber against the inner string is no use to anybody.

Formal rules aside, the practical question is different. Where do people genuinely place their feet?

Not, in my experience, at the mathematical centre. Descending, most of us drift toward the outer string, where the surface is wider and the handrail feels closer. Ascending, particularly when carrying something, the pattern varies more. Somebody moving a mattress upstairs hugs whichever side has clearance.

Which produces a small design tension:

• Set the walking line too far inboard and the effective depth shrinks, making descent feel steeper than the drawing suggests

• Set it too far outboard and the flight consumes more floor area than it needs to, since the outer sweep lengthens

• Set it thoughtfully, usually 400mm to 500mm from the inner string on a domestic flight, and both directions feel natural

Worth adding a caveat: this is judgement more than science. Two experienced designers will place that line differently on the same plan and both results will work perfectly well.

There's a second effect specific to curved work. The pitch is not constant across the width; it steepens toward the inside of the sweep and flattens toward the outside. Nobody experiences the whole width at once, so what matters is the pitch along the route people take. Quoting a single figure for a curved flight is therefore a slight simplification, though everyone in the trade does it anyway.

The Numbers We Aim For on Bespoke Work

Assuming a floor-to-floor height around 2.7m, which is common in newer Irish and UK homes, the arithmetic runs roughly like this.

Total Height	Number of Risers	Riser Height	Suits
2600mm	15	173mm	Generous halls, older occupants, formal spaces
2700mm	15	180mm	The comfortable default for most projects
2700mm	16	169mm	Very relaxed climb, needs a longer footprint
2900mm	16	181mm	Taller ceilings, contemporary schemes
3200mm	18	178mm	Period properties with high floor-to-floor heights

Notice how little the riser height moves across that table. Around 175mm to 182mm turns out to be the optimum band for domestic use, and it holds across wildly different houses. What actually changes is the count, and therefore the total run the flight demands. Our piece on how many steps a staircase needs works through that calculation in more detail.

A practical warning about measurement. Total height must be taken between finished floor levels, not structural ones. A 22mm engineered wood floor upstairs that nobody mentioned at design stage changes every step in the flight, and on a curved staircase you cannot simply pack out the bottom riser afterwards without the string geometry looking wrong. Confirm floor build-ups in writing. Twice, ideally.

Footprint follows from the numbers rather than the other way round, which surprises clients who arrive with a fixed opening in mind. Our guide to how much space a staircase requires covers what different forms demand.

Where These Figures Collide With Everything Else

Geometry never sits in isolation. Four collisions come up repeatedly.

Headroom. Reducing riser height lengthens the flight, which pushes the lower steps further into the room and can drop the clear height beneath a trimmer below the 2000mm benchmark. Shallow risers feel wonderful right up until you meet the ceiling.

Landings and turns. Curved flights absorb direction change gradually, so they rarely need a mid-flight landing in the way a dogleg does. That's a genuine advantage. Where the sweep is tight, though, the inner going contracts quickly, and at that point widening the flight helps more than adjusting the steps.

Balustrade. Riser height sets the rake of the rail, and rake determines whether balusters can be cut square or need individual angling. Spindles on a curve are rarely identical to one another. Glass infill panels have their own tolerance behaviour, and both approaches cost differently depending on the pitch you've chosen.

Material. Timber, concrete cladding and steel all impose slightly different minimum thicknesses beneath the walking surface, which affects how the geometry resolves at the top and bottom. The comparison in our overview of types of curved staircases is a reasonable starting point before fixing a design.

Why bother being this careful? Because the stakes are higher than they look. RoSPA's Safer Stairs campaign reports that falls on stairs and steps kill over 1,000 people annually in England and Wales, with roughly 43,000 further hospital admissions, and estimates that building to BS 5395-1:2010 would cut the chance of a fall by around 60%. Dimensional discipline is not pedantry.

If you'd like to see how we handle this on commissions, our bespoke curved staircases service page shows completed work, and the planning your staircase section sets out what we need from you at the outset.

Frequently Asked Questions

Can the going vary between steps on a curved flight?

No. Consecutive tapered steps must maintain a consistent going measured at the defined position, under both Approved Document K and Ireland's TGD K. What varies is the depth across each individual step, from narrow at the inner string to wide at the outer one. That variation is inherent to the geometry and entirely acceptable. Inconsistency between one step and the next is a different matter, and it is both a trip hazard and a certain inspection failure.

Does a shallower pitch always make a staircase more comfortable?

Not beyond a point. Very shallow flights, below roughly 30 degrees, disrupt natural gait because the stride no longer matches the step spacing, and people often describe them as tiring rather than restful. Most research and practice puts the comfortable zone between 30 and 38 degrees for domestic access. Shallower designs also consume considerably more floor area, so the gain is rarely worth the space penalty in a typical house.

How do open risers affect these calculations?

Open construction does not change the permitted riser height or going, but it adds requirements. In private dwellings, treads must overlap by at least 16mm, and no opening may allow a 100mm sphere to pass, which protects small children. Because the overlap eats into the effective depth, open designs often work better with a slightly deeper going than a closed equivalent. Discuss the detail early, since it influences string design and material thickness.

What happens if the existing opening cannot accommodate the ideal numbers?

Something has to give, and it's usually the opening rather than the geometry. Enlarging a floor void means trimming joists or introducing steel, which is structural work requiring building control notification. Accepting a steeper flight instead is possible within the 42 degree limit, though the result is noticeably less pleasant to use daily. Survey the structure before fixing a design, particularly in period properties where original fabric and headroom constraints complicate the options.

Ready to Work Through Your Numbers?

Getting this right on paper costs nothing. Getting it wrong once timber has been laminated to a curve costs a great deal.

Bavari designs, manufactures and installs custom staircases across Ireland and the United Kingdom for private clients, architects and interior designers. Send us your floor-to-floor measurements and a plan, and our team will work through the geometry with you before anything is committed.

Contact the Bavari sales team to arrange a consultation.