An anti-slip stair nosing does two jobs at the same time: it puts a high-friction surface exactly where the foot lands, and it marks the step edge clearly enough to be judged at a glance. Most stair falls happen on descent, and most of those happen because the edge was misread rather than because the surface was slippery — which is why grip and contrast matter equally.
This guide covers how the grip is achieved, how slip resistance is actually measured in the UK, how to size and specify a profile, and what the regulations require.
How the grip is actually produced
The metal or plastic body of a nosing provides almost no grip on its own. The friction comes from what is set into it:
- Carborundum and silicon carbide inserts — extremely hard abrasive particles bonded into the surface. The most durable option and the hardest wearing.
- PVC inserts — the commercial default. Good grip, chemical resistant, easy to clean, and replaceable when worn.
- Rubber inserts — softer, quieter, and compress slightly underfoot, which gives useful tactile feedback at the edge. Well suited to barefoot areas and indoor use.
- Ribbed or machined aluminium — grooves cut into the metal itself, which channel water clear rather than relying on a separate insert.
- GRP aggregate — grit bonded through a fibreglass body, so the grip does not wear off with a surface layer.
The insert is the wear part. On nearly every system it can be replaced without disturbing the profile, which is the single most useful thing to know about maintaining a stair.
How slip resistance is measured
In the UK, slip resistance is measured with the pendulum test to BS 7976 (now BS EN 16165), which produces a Pendulum Test Value. It is the only method the HSE recognises.
The number that matters is the wet one. Almost any surface performs well dry. The HSE benchmark is PTV 36 or above in the wet for low slip potential: 0–24 is high risk, 25–35 moderate, 36 and above low. For areas prone to contamination — oil, grease, food waste — specify 65 or above.
You will also see R ratings (R9 to R13) from the German DIN 51130 ramp test. That test uses motor oil and safety boots, so it describes an industrial floor rather than a rainy stair, and the two scales do not convert — a single R10 rating can correspond to pendulum results anywhere from 20 to 60. Ask for both figures and treat a supplier who can only quote an R rating as having given you half an answer.
Choosing the material
- Aluminium — the general-purpose choice. Corrosion resistant, takes heavy traffic, available in every profile shape and a wide range of finishes, and the insert is replaceable. Suits almost all indoor commercial and domestic work. Browse the aluminium range.
- GRP — the highest wet grip of the common materials and unaffected by salt or chemicals. The right answer for external, marine, industrial and wash-down stairs, though the finish options are functional rather than decorative.
- Stainless steel — maximum durability and impact resistance for heavy industrial and high-prestige commercial work. Specify marine grade near the coast.
The full anti-slip stair nosing range covers all three.
Sizing the profile
Two dimensions matter: how much of the tread the nosing covers, and how far it drops down the riser.
| Profile | Traffic | Typical setting | Fixing |
|---|---|---|---|
| 32 × 20mm | Light | Domestic stairs, thin coverings | Adhesive or screw |
| 40 × 25mm | Medium | Shops, small offices | Screw fix |
| 55 × 32mm | Heavy | Schools, hospitals, public buildings | Screw fix |
| 55 × 55mm | Heavy | Where the Part M contrast band applies | Screw fix |
| 70 × 30mm | Industrial | Factories, warehouses, external | Screw fix |
Measure the tread depth before choosing a width — the nosing has to leave a comfortable walking surface behind it. And measure every step individually: flight widths commonly vary by a millimetre or two in older buildings, which is enough to leave gaps at the ends.
Where the stair is in a building other than a dwelling, work to 55mm on both tread and riser, which is the band described in Approved Document M.
Contrast, lighting and visibility
Grip alone does not prevent the most common stair accident. Edge definition does.
Colour contrast is the cheapest and most effective measure: a light nosing on dark treads or the reverse. BS 8300-2:2018 puts a number on it — at least 30 points of Light Reflectance Value difference between the nosing and the tread. Ask suppliers for the LRV figure rather than judging by eye, because two colours that look different can measure very close.
Photoluminescent profiles charge from ambient light and glow for several hours after it goes out, with no wiring. They suit escape routes and heritage buildings where cabling is impractical.
Illuminated profiles carry an LED strip in the nosing itself, giving permanent edge definition in cinemas, stepped seating and unlit external stairs. See the 56 × 32mm illuminated profile.
Fitting over carpet
Carpet adds thickness, and that changes both the profile and the fixings. Choose a nosing with a deeper channel or an extended back leg that tucks under the carpet edge, such as the 3.22m square profile with a 50mm riser.
Cut the carpet cleanly around the profile rather than forcing a tight fit, which causes bunching and a raised edge. Use screws long enough to pass through carpet and underlay into solid material — a fixing that only bites into underlay is no fixing at all.
Outdoor stairs
External installations face temperature cycling, UV and standing water. Three things make the difference:
- Drainage. Choose a profile that lets water run off rather than pool on the grip surface. Standing water reduces friction and freezes.
- Fixings. Stainless steel only, A4 grade near the coast. Seal around fixing points to stop water tracking behind the profile and working it loose.
- Cleaning. Algae and moss fill the grip texture and are a common cause of a nosing that tests well when new and badly two winters later. Pressure washing works; keep the jet off sealant lines.
For fully exposed decking and walkways, GRP strips often suit better than a stair profile.
Installation in brief
Screw fixing is the default for anything commercial, external or carrying wheeled traffic. Adhesive suits smooth, sound, dry indoor substrates where fixings must be invisible. Space fixings at roughly 150mm centres on concrete, never fewer than three per step, and always one near each end.
Full detail, including substrate preparation and the mistakes that cause callbacks, is in our step-by-step installation guide.
Service life
Quoting one number for a two-part product is what makes published lifespans contradict each other. Taken separately:
- The extrusion — anodised aluminium commonly lasts twenty years or more in commercial service; stainless steel longer still.
- The insert — the wear component, typically ten to fifteen years in steady traffic and as little as five in heavy public use.
- GRP — a single-piece product with the grit bonded through it, guaranteed for ten years across our range and routinely beyond that indoors.
Replace the insert when the pattern has worn smooth rather than waiting for a slip. On a stair where risk has been formally assessed, a periodic in-situ pendulum test is the way to evidence that it still performs.
What the UK rules require
- Workplace (Health, Safety and Welfare) Regulations 1992, regulation 12 — law. Floors and traffic routes must not be slippery so as to expose anyone to risk.
- Approved Document K — stair geometry: going, rise and nosing projection.
- Approved Document M — access, and the source of the 55mm × 55mm contrasting band for buildings other than dwellings.
- BS 8300-2:2018 — a standard referenced by Part M, not law. Recommends at least 30 LRV points of contrast.
- Equality Act 2010 — a duty to make reasonable adjustments. It replaced the Disability Discrimination Act, so "DDA compliant" is trade shorthand rather than a current legal test.
A defensible non-domestic specification is a 55mm × 55mm profile, clearing 30 LRV points against the tread, achieving at least 36 PTV wet. Ask for the LRV and the pendulum data rather than accepting "compliant".
Frequently asked questions
What PTV do I need?
At least 36 in the wet, which is the HSE benchmark for low slip potential. Specify 65 or above where the stair sees oil, grease or food waste. Dry figures are close to meaningless because almost everything passes dry.
Is a DDA compliant nosing legally required?
"DDA compliant" is industry shorthand rather than a legal standard — the Disability Discrimination Act was replaced by the Equality Act 2010. What applies in practice is Approved Document M for non-domestic buildings, plus the Equality Act duty to make reasonable adjustments.
How long does anti-slip stair nosing last?
Depends which part. An anodised aluminium extrusion commonly lasts twenty years or more, and stainless longer. The insert is the wear part and is normally replaced every ten to fifteen years without removing the profile. GRP is a single piece and guaranteed for ten years across our range.
Can I install it myself?
Screw-down fitting is within most competent DIY ability with the right tools. Anything involving electrical connection, or a commercial stair where compliance has to be documented, is worth having fitted professionally.
Will it work outdoors in all weather?
Yes, with the right material and fixings. GRP and marine-grade aluminium both hold grip when wet and resist freeze-thaw. Use stainless fixings, seal around them, and keep algae off the grip surface.
What maintenance does it need?
Clean to suit the traffic with mild detergent, keeping polish and wax off the inserts. Check fixings annually. Replace inserts once the surface pattern has worn flat.
Specifying with confidence
Four questions settle most specifications: what is the environment, what PTV does it need to hold wet, does Part M apply, and what is the stair finished in. Browse the anti-slip stair nosing range by material and profile, or send us the step dimensions and the setting and we will specify against them.