New Banister Spindles

New banister spindles, also called balusters or stair balusters, are one of the most cost-effective ways to transform the look of a staircase. A full set of replacement spindles on a standard 13-tread straight flight typically costs £150–£800 for materials, depending on whether you choose softwood, oak, metal, or glass. Most homeowners can fit pine or metal spindles themselves in a weekend; oak and glass are better left to a joiner.

The single most important thing to get right before you buy anything is compliance with Building Regulations Approved Document K (Protection from falling, collision and impact). The maximum permitted gap between spindles is 99 mm, a 100 mm sphere must not be able to pass through any opening in the balustrade. This rule applies to new staircases and any material alterations to an existing one.¹

Spindle Types and Materials

Pine (Softwood)

Painted softwood spindles are the traditional British staircase staple and remain the cheapest option. Typically available in 32 mm square, 41 mm square, and turned profiles, they are easy to cut, sand, and finish. Pine spindles take paint well but will show dents and scuffs more readily than hardwood over time.

Sizes: 32 mm square × 895 mm standard height; 41 mm square also available. Turned profiles (with a barrel or vase shape) are a common decorative choice.

Cost: £2–£6 per spindle. A standard flight (26 spindles) costs £52–£156 for materials.

Oak (Hardwood)

Oak spindles are the premium timber option and suit both traditional and contemporary interiors. They can be left natural (oiled or lacquered) or painted. Oak is harder and heavier than pine, which makes cutting and fitting slightly more demanding. Oak is almost always used where the handrail and newel posts are also oak, as mixing hardwood and softwood is visually inconsistent.

Sizes: 32 mm and 41 mm square most common; 900 mm and 1,100 mm lengths to suit different floor-to-floor heights. Prism and stop-chamfered profiles are common contemporary choices.

Cost: £8–£18 per spindle. A standard flight costs £208–£468 for materials.

Metal (Steel and Wrought Iron Style)

Metal spindles, usually mild steel powder-coated in black, chrome, or antique brass, or genuine wrought iron, offer a contemporary or period look with minimal visual bulk. They are particularly popular in open-plan homes where a slender profile keeps sightlines clear. Metal spindles are fixed with top and bottom cups, threaded connections, or welded brackets depending on the type.

Sizes: Typically 12–16 mm round bar, 900 mm or 1,100 mm; square section 12×12 mm also available. Twisted, basket-weave, and plain bar styles are common.

Cost: £5–£25 per spindle for standard powder-coated steel. Genuine hand-forged wrought iron can reach £30–£60 per spindle.

Glass

Glass balustrades and glass-infill spindle panels are the most expensive option and are usually specified on contemporary staircases where an open, light-filled feel is the priority. These are almost always installed by a specialist because the glass panels must be structurally rated (typically toughened laminated 10 mm or 17.5 mm), and the channel or clamp fixings must meet Part K load requirements.¹

Glass is typically used as full panels between newels rather than individual spindles. Costs are quoted per panel or per linear metre rather than per spindle.

Cost: £80–£250 per panel (600 mm wide) or £150–£400 per linear metre installed. DIY glass fitting is not recommended.

LVL and Engineered Timber

Laminated veneer lumber (LVL) spindles have emerged as a cost-effective hardwood alternative. They use thin layers of veneer bonded under pressure to produce a dimensionally stable, knot-free product that accepts stain and oil well. LVL spindles look like solid hardwood at a lower price point and with less waste on cutting.

Cost: £6–£14 per spindle.

Material and Cost Comparison

Building Regulations Part K: What You Need to Know

Approved Document K sets the structural and dimensional requirements for staircases, ramps, and protective barriers. The key rules for spindles are:

Maximum gap: The openings in any balustrade, including gaps between spindles, between a spindle and the stringer (the angled side board), and between the bottom of the handrail and the top of the string, must not allow a 100 mm sphere to pass through. In practice this means centre-to-centre spindle spacing of no more than 120–125 mm for a 32 mm spindle, and no more than 130–135 mm for a 41 mm spindle, but always verify by measuring rather than relying on rules of thumb.

Handrail height: On a stair, the handrail must be at least 900 mm above the pitch line (an imaginary line connecting the nosings of the treads) and no more than 1,000 mm. On a landing, the minimum is also 900 mm measured vertically from the floor. On stairs serving a building used by children under 5 (homes with young children, schools), there should be no horizontal rails that could be used as a ladder.

Structural load: The balustrade must be capable of resisting a horizontal force of 0.36 kN/m (approximately 36 kg per metre) on residential stairs, and 0.74 kN/m on commercial or public staircases. This is why glass panels, metal systems, and newel post connections must be structurally engineered rather than assumed to be adequate.

When Do You Need Building Regulations Approval?

Replacing like-for-like spindles in an existing staircase is generally classed as a repair or replacement and does not require a formal Building Regulations application, provided the work maintains compliance with Part K (or at minimum does not make compliance worse). However:

• If you are removing spindles and replacing them with a glass panel system, that is a material alteration and Building Regs approval is required.
• If you are changing the staircase configuration, moving the newels, changing the stringer, altering the handrail height, Building Regs approval is required.
• If your staircase currently has gaps wider than 99 mm and you are doing any work to the balustrade, building control will expect the gap issue to be rectified at the same time.

In most cases, a Building Notice (paid to your local authority building control) or an application through a registered building control approver (the private-sector route, called an approved inspector before April 2024) is the appropriate route. Fees vary by authority but typically run £150–£350 for a staircase-only application.

How to Count the Spindles You Need

The number of spindles on a staircase depends on three things: the number of treads, the width of each tread, and the spacing required to meet the 99 mm gap rule. A practical method:

1. Measure the going (horizontal depth) of a typical tread, usually 220–250 mm for a standard domestic stair.
2. For a 32 mm spindle, allow two spindles per tread as a starting point. For an open-plan stair with wider treads, you may need three.
3. Add spindles for any landing section, measured at one spindle per 100–110 mm of landing run.
4. Add 10% for waste and cutting.

Example: A 13-tread staircase with 230 mm going and 32 mm square spindles.

• 13 treads × 2 spindles = 26 spindles
• Landing run of 1,200 mm ÷ 110 mm = 11 spindles
• Total: 37 spindles, plus 10% waste = 41 spindles to order

Always mark out the spacing on the stringer before cutting or ordering, and use a spacer block to check the gap measurement is under 99 mm before fixing any spindle.

DIY vs Joiner Installation

DIY is practical for pine and metal spindles on a standard flight where the newels, handrail, and strings are staying in place. The key tools are a mitre saw (to cut spindles to the angled pitch line), a chisel (to cut mortises in handrail and string if using mortise-and-tenon fixing), and a drill. Screwed or dowelled fixings into pre-routed channels (the system used by most modern staircase suppliers) are the easiest DIY approach.

Hire a joiner if: you are fitting solid oak spindles with a traditional mortise-and-tenon joint (the angled cuts require precision); you are installing glass panels (structural fixing and sealing require specialist knowledge); your staircase has unusual geometry (winders, curved strings, open riser details); or you need Building Regs sign-off on the finished work. A joiner typically charges £250–£600 for a full spindle replacement on a standard flight, plus materials, taking 1–2 days.

Cost Summary: Full Spindle Replacement, Standard 13-Tread Staircase

These figures cover spindles, handrail if replaced, and fixing consumables. They exclude newel post replacement, stringer repair, or decorating.

The rules in this note are those that apply in England. Scotland, Wales and Northern Ireland have their own building standards and permitted development rights.