Building components · Stairs & Level Change
Winder Tread
Explains the winder as a tread whose defining property is that it turns the flight, and why that makes its position in the turn — rather than its material — the thing that governs it.
Educational reference entry. What this element has to do, and whether any particular arrangement of it is adequate, depends on the whole assembly, the loading, the exposure, local requirements, the manufacturer's instructions and qualified professional design.
Overview
What a winder is
A winder tread is a tread that tapers: wider at the outside of a turn and narrower at the inside. A group of winders turns a flight through a corner while the stair continues to rise, so the stair changes direction without a level platform being introduced.
What makes the winder a distinct position rather than an odd-shaped tread is that the walked surface is no longer the same at every point across it. A person taking the inside of the turn meets a very different step from one taking the outside, and that variation is the whole reason winders are treated separately in stair design, in stair construction and in how a stair is assessed.
Boundaries
How it differs from nearby elements
The distinctions that keep this entry from being a restatement of its neighbours.
- It is not an ordinary tread. A tread in a straight flight presents the same step wherever it is crossed; a winder presents a different step at its narrow end than at its wide end, which is a difference in kind rather than in shape alone.
- It is not a landing. A landing interrupts the rise and is level; a group of winders continues to rise through the turn, which is precisely the trade being made when winders are used instead of a landing.
- It is not a stair nosing profile. The nosing profile is a procured trim published as a material entry and terminates a covering at the step edge; on a winder that edge is not parallel to the one below it, but the trim is still a separate thing from the position it is fitted to.
Terminology
Common names and aliases
These names describe the same element. The library keeps one entry per component so that a trade term or a regional name never becomes a second, thinner page.
- winder
- kite winder
- turning tread
- tapered tread
Dependencies
What it depends on
What has to be right elsewhere for this element to do its job.
- Where it sits within the group of winders forming the turn, since the first, middle and last of a set are not interchangeable.
- How the set of winders relates to the straight flights either side, because the rise has to remain consistent across the junction between them.
- What carries the narrow end, which reaches a point or a newel rather than a full-width bearing and is the most constrained support in the flight.
- How the walked line through the turn is expected to run, since the usable part of the step is not the whole of it.
Considerations
Topics that genuinely apply here
Subjects worth discussing about this element. These are discussion topics, never measured values, ratings or performance claims.
Winders are the point where a flight's geometry is hardest to keep consistent, because the turn changes the plan while the rise has to continue unchanged.
The narrow end of each winder converges on a single support, so a small area is asked to receive several steps rather than one.
Winders are commonly the part of a stair that is made to fit the opening rather than to a standard, which makes an accurate survey of the opening the governing input.
Wear on a winder concentrates along one part of the turn rather than across the step, because people take a consistent line through a corner.
Materials
Commonly formed from
Material families this element is commonly realised in. This states common practice only — it is not a statement that any of these materials suits this component in a particular building, which depends on the whole assembly and on qualified review.
Materials
Commonly incorporates
Materials this element commonly contains as a distinct constituent part, rather than being made of.
Assemblies
Building systems this element is met in
The role this component fills inside each assembly. A role describes what the element does there — it is not a statement that this component suits that system in any particular building.
Related elements
Neighbouring components
Typed relationships to other elements. There is deliberately no generic “related” category: an edge that cannot be classified does not exist.
Clarifications
Commonly misunderstood
- That winders are simply a space-saving version of a landing. They change how the stair is used through the turn, not only how much floor area it occupies.
- That all the winders in a turn are the same component repeated. Each occupies a different position in the turn and relates differently to the flights either side.
Conversations
Questions for qualified professionals
Questions worth asking someone with the project in front of them. This page cannot answer them.
- How many winders form this turn, and how do they relate to the straight flights either side?
- What carries the narrow ends of the winders where they converge?
- How has the rise been kept consistent between the winders and the flights above and below?
- Where winders are being introduced into an existing stair, what has been assessed about the opening and the structure around it?
Go deeper
Related Build Design Hub guides
Planning guidance behind the decisions this element involves.
Preparation
Related planning checklists
Owner-side preparation before the conversation where this element comes up.
What this entry does not do
- This entry describes a position within a turning flight. It states no going, rise, taper, width at any point, headroom or load capacity, and none can be inferred from it.
- Whether winders are permissible in a given stair, and in what arrangement, follows from local requirements and from who uses the stair; that determination is not made here.
Stair & Level Change Elements
The positions that make up a stair and the elements that carry people safely between levels — treads, risers, the members beneath them, and the guarding at the edge.
Browse all stairs & level change entries →