Stair Parts Explained: Newel Posts, Handrails, Spindles and More

If you’ve ever tried to describe a part of your staircase to a joiner, looked up a product listing for a balustrade kit, or simply wanted to understand what you’re looking at before starting a refurbishment, the terminology can be a real stumbling block.

Words like baluster, spindle, newel, and baserail are often used interchangeably, even by people in the trade. That makes it genuinely difficult to know what you’re ordering or what a quote is referring to.

This guide covers the main parts of a staircase in plain terms. It also addresses the terms that cause the most confusion, and includes a section on which parts are relevant if you’re planning a balustrade refurbishment rather than a full staircase replacement.

The Main Parts of a Staircase

These are the structural elements that form the staircase itself. When homeowners refurbish their stairs, these components typically stay in place. It is the balustrade assembly that changes.

The step components of a staircase

Tread The horizontal surface of each step, and the part you walk on. For domestic staircases, UK building regulations specify a minimum going, which is the front-to-back depth of each tread.

Riser The vertical face between one tread and the next. Staircases with riser boards are described as closed-riser; those without are open-riser. The maximum individual rise for a domestic staircase is set out in Part K. 

Nosing The front edge of the tread that overhangs the riser below. Nosings make each step edge more visible and provide a small amount of grip underfoot.

The structural components of stairs

Stringer (string) The board running diagonally along the side of the staircase, supporting the treads and risers. There are two main types:

• Closed string: the step profile is hidden from view at the side
• Open (cut) string: the board is cut to follow the shape of the steps, leaving the tread and riser edges visible from the side

Wall string The stringer fixed flush against the wall, also called the wall-side string.

Landing The flat platform at the top of a flight, or between two flights where the staircase changes direction.

• Quarter landing: the staircase turns 90 degrees
• Half landing: the staircase turns 180 degrees

Balustrade Parts Explained

The balustrade is the safety assembly running along the open side of the staircase. It prevents falls and, in domestic properties, must meet minimum height and spacing requirements under UK building regulations.

It is made up of several components, each with a distinct role.

A Closer Look at Newel Posts

Newel posts are structural, not decorative. They carry the load of the handrail and anchor the whole balustrade system.

They come in two main styles:

• Turned newels: rounded, with a traditional profile
• Box newels: square-sided, better suited to contemporary interiors

Common newel cap styles include ball, acorn, and flat square. The cap is mainly decorative, though it also protects the end grain of a timber newel post.

Spindles and What to Know About Spacing

UK building regulations require that spindles are spaced so that a 100mm sphere cannot pass between them. This is to prevent young children from becoming trapped or falling through the gaps. 

Spindles can be made from:

• Timber (square, turned, or shaped profiles)
• Metal (steel or wrought iron style)
• Glass panels (toughened safety glass)

The material you choose affects which type of base rail and handrail system is needed, so it is worth deciding on this before taking measurements.

Terms That Often Cause Confusion

Several stair parts share similar names or are used interchangeably in everyday speech. Here are the most common ones worth knowing.

Baluster vs Spindle

These refer to the same component.

• Spindle is the term most commonly used in the UK, both by homeowners and in product listings
• Baluster is the traditional trade term, also widely used in US English

The full safety assembly, including handrail, spindles, base rail, and newel posts, is called the balustrade.

Handrail vs Banister

In everyday use, most people treat these as the same thing.

• Handrail refers specifically to the rail you grip
• Banister is an informal term, sometimes used to mean just the handrail and sometimes the whole balustrade system

In product listings, specifications, and building regulations, handrail is the correct term to use.

Baluster vs Newel Post

Both are vertical elements, which is why they are easily confused. The difference comes down to size and function.

Riser vs Tread

• Riser: the vertical face of a step
• Tread: the horizontal surface you walk on

A straightforward way to keep them straight: the tread is what you tread on.

Which Parts Are Relevant for a Balustrade Refurbishment?

When updating a staircase, most homeowners do not need to touch the structure at all.

The structural parts, including treads, risers, and stringers, almost always stay in place. The refurbishment focuses on the balustrade assembly only.

A typical balustrade refurbishment includes the replacement of:

• Newel posts
• Spindles or glass panels
• Handrail
• Base rail
• Newel caps

Made-to-measure balustrade kits are produced to fit your existing staircase dimensions. Components arrive pre-cut and pre-drilled, which removes the need to source and cut individual parts. StairFurb kits include video guides covering each stage of fitting, making the process straightforward for a competent DIYer.

Worth checking at the same time

A refurbishment is a practical point to verify whether the existing balustrade meets current regulations. If spindle spacing is wider than 100mm, or the handrail height falls below the required minimum, replacing the balustrade brings the staircase up to standard at the same time. 

A Note on Staircase Materials

The material used for spindles and handrails affects both the look of the finished staircase and how components are installed.

Timber 

Traditional balustrades use timber spindles, typically in oak or pine, with matching handrails and newel posts. These suit period properties and more traditional interiors well and can be painted or stained to match existing woodwork.

Metal 

Metal spindles, usually in steel or with a wrought iron style finish, offer a more contemporary look while keeping the traditional post-and-rail format. They are often combined with oak handrails and newel posts.

Glass 

Glass panels are increasingly used in place of spindles, particularly where homeowners want to open the staircase up visually and allow more light through the space.

Glass used in balustrades must be toughened safety glass. 

Each panel is cut to size and polished on all edges. The installation method differs from timber or metal spindles. Glass panels typically sit into a grooved base rail or are held in place with stainless steel clamps fixed to the handrail.

Frequently Asked Questions About Stair Parts