Types of staircase: the main shapes, and how to choose

Staircases come in a handful of basic shapes, and most of the choice comes down to three things: how much space you have, the look you are after, and the budget. None is simply better than another, they suit different jobs. Here are the main types and where each one earns its place.

Straight

A single flight in a straight line. It is the simplest to make and the cheapest, the easiest to fit, and the most comfortable to walk. Its one demand is floor length: it needs a clear run for the whole rise, which not every space has. A long straight flight to a full storey may also need a landing to break it.

Quarter-turn (L-shaped) and half-turn (U-shaped)

A quarter-turn makes a 90 degree turn, usually with a landing, so the stair runs into a corner and takes up less length along any one wall. A half-turn, also called a U-shaped or dog-leg stair, turns back on itself through 180 degrees, which packs the stair into a compact footprint and is very common in houses. Both use landings to make the turn comfortable.

Winder

A winder turns the stair using tapered, wedge-shaped treads instead of a flat landing. It saves the space a landing would take, which is why it is common in tighter houses, but the tapered treads are harder to walk and there are specific rules about the going measured on the walk line. More detail on winder staircases.

Spiral and helical

A spiral stair winds around a central column in a tight circle, and it has the smallest footprint of any stair, which makes it the go-to where space is very limited. A helical stair is the grand cousin: it curves in a sweeping arc with no central column, an open, sculptural feature. Helical stairs are the most expensive to make because the strings and handrails have to be formed to a curve. Both spiral and helical stairs have their own dimensional standard, referenced on the building regulations page.

Space-saver (alternating tread)

A space-saver, or paddle stair, has treads cut back alternately so you lead with a set foot, letting it sit at a steeper pitch in a very small footprint. It is genuinely a last resort, allowed only in tight, specific circumstances such as access to a single room, and it cannot be the sole escape from a loft without meeting fire rules. See space-saver stairs.

Open or closed string, and open riser

On top of the shape, a stair can have a closed string (a solid outer board) or a cut, open string that shows the step ends, and it can have solid risers or open risers with a gap between the treads. Those choices change the look and the cost without changing the basic type. See cut string vs closed string.

How to choose

Start with the space. If you have the length, a straight flight is the simplest and most comfortable. If you do not, a quarter or half-turn folds the stair into a corner, a winder saves the landing, and a spiral squeezes into the smallest footprint of all. Then the look and budget decide between them: a helical stair is a statement and a cost, a space-saver is a compromise for a tight spot. Whatever the shape, it still has to meet the same rise, going, pitch and headroom rules, and the choice moves the price, as covered in what drives the cost of a staircase.