Stair treads and steps

What to consider

Measure every step

Concrete stairs are rarely perfectly regular. Measure the width, going (depth) and rise of each step rather than assuming they match, and number them from the bottom. Uneven risers are a trip hazard that stone cannot hide, so they should be corrected in the structure or bedding.

Nosing and edge

The front edge takes the knocks. Common options are a rounded or bullnose edge, a small chamfer, or a square edge with a slight arris; the fabricator cuts these. Decide how far the nosing projects over the riser, and keep it the same on every step.

Slip at the nosing

Most slips on stairs happen at the front edge. Grooves cut near the nosing, inserted anti-slip strips or a textured band are common measures. Which one is needed depends on use and on whether the stair can get wet, which your designer decides.

Landings, risers and skirting

Landings are larger than treads and may need cutting from slabs, which affects material choice. Decide whether risers and stair skirting (stringers) are in the same stone, and which way any pattern runs, before ordering.

Visibility

Strongly patterned or very dark treads can make the edge of each step hard to see. A contrasting nosing strip or lighting is sometimes added for that reason; ask your designer.

Limitations and when to get technical advice

External stairs, stairs near pools, and stairs in public or commercial buildings have slip and safety requirements set by the designer and local authority; we hold no slip test data, so those cases need technical review with test evidence. Cantilevered, floating or spiral stairs, and any tread spanning between supports rather than bedded on concrete, are structural and must be designed by an engineer. Dark Emperador marble is softer than granite and its nosings wear and dull faster on a busy stair. Our porcelain slabs are 15 mm and are not offered as stair treads; porcelain stair products are specific manufactured items. Black Marquina’s family is unconfirmed, so check it before relying on granite assumptions.

Finish

Finishes for the listed steps are not documented and are confirmed in your quotation. In general, polished treads look sharp but can be slippery when wet, dusty or in socks; honed treads are less reflective and usually less slippery, though not automatically suitable for wet stairs. A polished tread with grooves or a textured strip near the nosing is a common compromise indoors. Agree the finish with your designer; see our finishes guide.

Thickness

The four step products are 30 mm. Treads cut from slabs can be 20 mm or 30 mm. A 30 mm tread is common on stairs because it gives a solid nosing and tolerates impact; a 20 mm tread is usually fully bedded and may be given a built-up front edge. A tread that bridges a gap, overhangs significantly or forms part of a floating stair needs an engineer’s design, whatever the thickness.

What to measure

Number the steps from the bottom and measure each one. Give widths and depths in metres or millimetres (say which), and note any tapered or winder steps separately with a sketch. Include landings and the side skirting if they are in stone.

• Number of treads
• Tread width across the stair (m)
• Tread depth / going including nosing (m)
• Riser height (m) and number of risers
• Landing length × width (m)
• Nosing projection over the riser (mm)

List stair items as pieces: the number of treads, risers and landings, each with its size, and any skirting in linear metres. Treads of the same size can be grouped (“14 treads at 1.20 × 0.33 m”). Ask your contractor whether to order one or two spare treads from the same lot, since a broken nosing is hard to match later.

What we supply

We supply steps and slabs. Cutting treads to the sizes of your stair, nosing profiles, grooves and fixing are normally done by your fabricator and installer. Some past deliveries were cut-to-size steps, landings and skirting, so if you need pieces cut to your schedule, ask and we will confirm whether it can be arranged before quoting.

Site conditions to tell us

• Stair structure complete and cured, with rises and goings measured on site.
• Whether an existing finish must be removed first.
• Positions of balusters or handrail fixings, which may need holes through the treads.
• Whether the stair is internal, external, or exposed to water.
• Carrying route to upper floors for heavy treads and landings.
• Whether the stair must stay in use during the works.

Natural variation

On a stair, treads sit side by side and one above another, so differences between pieces are easy to compare. Even, speckled materials such as Black Galaxy and Colonial White generally hide variation better than strongly patterned ones such as Viscon White, whose bands change markedly from slab to slab in our photographs. Lay out the treads before fixing and arrange them so that changes are gradual. See natural variation.

Technical documents

If your designer, consultant or client needs technical documents such as test reports, data sheets or certificates, list them in your request and we will tell you what can be provided for the materials you choose.

What affects the cost

• Number and size of pieces, especially treads longer or deeper than standard steps.
• Whether treads come from ready steps or must be cut from slabs.
• Thickness (30 mm steps, or 20 / 30 mm slab).
• Material and grade (meanings of Standard, Premium and Extra confirmed with your quotation).
• Landings, risers and skirting in addition to treads.
• Fabrication extras such as nosing profiles and anti-slip grooves, priced by the fabricator.
• Delivery and carrying to upper floors.

Delivery preparation

Treads are heavy and their finished nosings chip easily, so they should travel with edge protection and be stored flat or on edge on timber, not on bare concrete. If pieces are cut to a schedule, ask for each one to be labelled with its step number. Agree who carries them to upper floors. Terms are confirmed in your quotation; see delivery preparation.

Samples and viewing

Ask whether a sample or a yard visit is possible. For stairs, seeing a full step piece is particularly useful, because it shows the nosing thickness and how the pattern sits at the front edge.

Care

Grit wears nosings first, so sweep or vacuum stairs regularly. Clean with a pH-neutral cleaner and do not leave stairs wet after mopping; clean one side at a time if the stair is in use. Check anti-slip grooves or strips and keep them free of dirt and wax. Avoid polishes that increase gloss, which can make treads more slippery. See the granite care guide.

Alternatives

Ready steps in Black Galaxy, Colonial Gold, Colonial White or Viscon White are the most direct option in our range. Treads cut from slabs widen the choice of colour, at the cost of fabrication. Marble treads give a softer, warmer look but wear faster at the nosing; see granite vs marble. For external steps, also read our landscape detailing and outdoor paving pages, and involve your designer early.