Cut string vs closed string staircase: the difference, and how to choose
Written by Scott Jones, The Stair Guys, independent staircase measuring and sourcing specialists·Last updated
The string is the long raking board that runs up each side of a flight and carries the steps. On the side against the wall it is nearly always a closed wall string. On the open side, facing into the room, you have a choice, and it changes both how the stair looks and what it costs. That choice is closed string or cut string.
Closed string
A closed string keeps the outer edge as a solid board that runs in a straight raking line from bottom to top, with its top edge above the line of the steps. The treads and risers are housed into routed grooves on the inside of the string and driven tight with glued wedges from the underside, so from the side you see a clean board, not the steps. The balustrade sits on a baserail along the top of the string. It is the simpler build, it hides everything, and it is the practical, more affordable choice, which is why it is the common one, especially where the stair will be carpeted.
Cut (open) string
A cut string, also called an open string, has that outer board cut away to follow the profile of the steps, so the end of each tread and the return of each riser are on show from the side. Good work finishes those tread ends with a mitred, returned nosing so the end grain is hidden, and there is often a small bracket detail under each step. The spindles usually land on the treads themselves, commonly two to a tread, rather than on a baserail. It is noticeably more joinery and more setting out, so it costs more, but it is a feature staircase where the craftsmanship is meant to be seen.
Which to choose
Neither is better, they are different jobs. A closed string suits a practical family staircase, a carpeted flight, or a budget that wants the money spent where it shows most, and it hides the step profile entirely. A cut string suits a stair that is a feature in the space, a period or open-plan look where the timber and the step detail are on display. The trade-off is straightforward: cut string is more work and more cost, closed string is cleaner and cheaper. It is one of the choices that moves the price, so it is worth deciding early. See what drives the cost of a staircase and the parts glossary.
Frequently asked
What is the difference between a cut string and a closed string staircase?+
On a closed string the outer board is solid and hides the ends of the treads and risers, which are housed and wedged in from behind. On a cut or open string that outer edge is cut to the shape of the steps, so the tread ends and returned nosings are visible from the side. Closed is simpler and cheaper, cut is more decorative and more joinery.
Is a cut string or closed string staircase cheaper?+
Closed string is cheaper. It is a simpler build that hides the step ends behind a solid board. A cut string is more work, with the outer string shaped to the steps, mitred returned nosings and often bracket detailing, so it costs more.
What is an open string staircase?+
Open string is another name for a cut string. The outer string is cut to follow the profile of the steps so the tread ends show from the side, usually finished with returned nosings and with the spindles landing on the treads. It is the more decorative, feature option.
Related guides
- Winder staircases: what they are and the rules that govern themA winder staircase turns a corner on tapered treads instead of a flat landing. Here is how winders work, the two rules every winder has to keep, why four winders is a harder job than three, and when a landing is the better answer.
- Types of staircase: the main shapes, and how to chooseThe main staircase types are straight, quarter-turn, half-turn, winder, spiral, helical and space-saver, with open or closed strings on each. The right one is driven by the space you have, the look you want and the budget.
- Space-saver (alternating tread) stairs: what they are and when you can have oneWhat a space-saver or alternating tread staircase is, when building regulations actually allow one, the trade-offs, and why it is a space and budget compromise rather than a premium upgrade.
- Mono-stringer and central-spine staircasesA mono-stringer or central-spine staircase carries the treads on a single central beam instead of two side strings, giving a lighter, floating look. The spine can be steel or a thick timber beam, and the treads cantilever out to each side.
- Cantilever (floating) staircasesA cantilever or floating staircase fixes each tread at one end only, usually built into the wall, so the treads appear to float with no support on the open side. The wall and a steel support carry the load, so it is a structural, engineered stair rather than standard joinery.
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