Most stair nosing failures are not product failures. They are fitting failures — a nosing bonded to a damp substrate, cut with no expansion clearance, or screwed down the centre of the tread where every footfall works it loose. Get the preparation and the fixing method right and the profile will outlast the floor covering around it.
This guide covers surveying and measuring, substrate preparation, cutting, choosing between adhesive and mechanical fixing, and the mistakes that generate callbacks.
Before you start: fitting job or repair job?
A nosing is an edge protector, not a structural repair. If the step edge is crumbling, spalled or has more than a few millimetres of material missing, that has to be made good first — the nosing needs a sound, continuous bearing surface or it will flex, and flexing is what cracks fixings out of concrete.
Fill damaged edges with an epoxy repair mortar and let it cure fully before you fit anything. On timber, replace or splice any softened or split nosing timber rather than covering it. A profile screwed to rotten timber is a trip hazard waiting to happen.
Tools and materials
- Tape measure, pencil, straight edge — the straight edge matters more than people expect for sighting a flight
- Hacksaw, mitre saw or angle grinder with a metal or masonry cutting disc, depending on material
- Fine file or emery cloth for deburring
- Drill with masonry, HSS or wood bits to suit the substrate
- Countersink bit if the profile is not pre-drilled
- Stainless steel screws and appropriate plugs — A2 indoors, A4 for coastal and external work
- Degreaser (acetone or isopropanol) and clean rags
- Structural adhesive where relevant — two-part epoxy or polyurethane, not general-purpose grab adhesive
- Moisture meter if you are bonding to concrete or screed
- Safety glasses, gloves and a dust mask — essential when cutting GRP
Step 1: Survey and measure
Measure every step individually. In older buildings, flight widths commonly vary by several millimetres between top and bottom, and a set of nosings all cut to the same length will bind on some steps and leave gaps on others.
Three numbers matter on each step:
- Width — wall to wall, or wall to open string
- Tread depth available — determines the maximum profile width you can fit without intruding on the walking surface
- Riser condition — decides whether you need a full-face profile or a shallow one
Deduct 2–3mm from the measured width at each end. Aluminium and GRP both move with temperature, and a profile cut to the exact width will bow or crack when it expands. That small clearance is invisible once fitted and it is the single most-skipped step.
Step 2: Prepare the substrate
Sweep, then vacuum, then degrease. Old adhesive residue must come off completely — new adhesive bonds to the old residue, not to the stair, and the whole assembly lifts as one.
On concrete, wire brush or lightly grind back to sound material. On steel, remove rust and prime. On timber, make sure the surface is sound and dry, not merely dry on top.
Moisture is the biggest hidden cause of adhesive failure. Concrete and screed should read below about 4% moisture content before you bond to them. If you cannot test it, use mechanical fixings instead — a screw does not care how damp the substrate is.
Step 3: Cut to length
Support the full length of the profile on both sides of the cut. An unsupported end will snatch and distort as the blade breaks through.
- Aluminium — hacksaw, mitre saw or angle grinder with a metal cutting disc. Use a fine-toothed blade; a coarse one tears the extrusion and leaves burrs that are hard to file out.
- GRP — angle grinder with a cutting disc or a fine-tooth saw. GRP cuts cleanly but throws glass fibre dust, which is a skin and respiratory irritant. Mask, glasses, and cut outdoors or with extraction.
- PVC and rubber — fine-tooth saw or a sharp knife on thinner sections. Warm material cuts more cleanly than cold.
Deburr every cut end with a file or emery cloth. On anodised or powder-coated aluminium, touch in the exposed cut — that bare edge is where corrosion starts.
Step 4: Choose the fixing method
This is the decision that determines whether the installation lasts. Match the method to the substrate and the traffic, not to what is quickest.
| Method | Right for | Avoid when |
|---|---|---|
| Screw fixing | Concrete, timber, steel; any commercial or high-traffic stair; all external work | Drilling is prohibited, or the substrate is too thin to hold a fixing |
| Structural adhesive | Smooth sound concrete, tiled steps, listed buildings, where fixings must be invisible | Damp, porous, rough or dusty substrates; below 5°C; heavy trolley traffic |
| Self-adhesive | Light domestic use on smooth, clean, dry surfaces | Any commercial stair, anything external, any surface already failing |
| Push-in | Laminate and engineered board with a machined lip | Retrofit onto surfaces with no receiving channel |
| Adhesive plus screws | Hospitals, care homes, schools, public buildings — anywhere failure is unacceptable | Rarely wrong, but it is slower and harder to remove later |
As a rule of thumb: if the stair is public, external, or takes wheeled traffic, screw it down. Adhesive alone is a domestic and light-commercial method.
Step 5: Fix the profile
Screw fixing
- Dry-fit and mark. Position the profile with its clearance at each end and mark through the pre-drilled holes.
- Drill. Masonry bit and nylon plugs into concrete, HSS into steel, pilot holes into timber. Go about 5mm deeper than the screw length so debris has somewhere to go.
- Set your spacing. Fixings at roughly 150mm centres on concrete is the standard. On steel, every second hole — around 300mm — is usually enough. Never fewer than three per step, and always one near each end, because unsupported ends are what catch a toe.
- Keep fixings out of the wear line. The centre of the tread takes the most footfall and works screws loose fastest.
- Tighten to flush, then about a quarter turn. Over-torquing dishes aluminium and cracks GRP around the countersink. Snug, not tight.
Adhesive fixing
- Degrease the substrate and abrade the underside of the profile with 60-grit paper.
- Apply continuous beads along the length rather than dabs — dabs leave voids that drum underfoot and let water track in.
- Press the profile down across its whole length, not just the ends.
- Weight or clamp it until cured. Sandbags work; so does a run of timber and a few bricks.
- Allow the full cure, typically 24 hours at 20°C, before any foot traffic. Cold slows this considerably.
Substrate temperature needs to be above about 5°C for a reliable cure, which makes adhesive a poor choice for winter external work. Double-sided nosing adhesive tape is available for lighter-duty bonding where a full structural adhesive is not warranted.
Self-adhesive
Peel back only the first 100mm of backing, position and align the whole length, then press that first section down. Peel the rest progressively while pressing as you go. Once it touches down it will not reposition cleanly, so align before you commit.
Step 6: Work up the flight
Fit from the bottom step upwards. It keeps you off the work you have just completed and lets you sight up the flight to check alignment as you go.
After every two or three steps, stand back and look along the nosing line. Consistent projection matters more than perfect individual placement — the eye reads the line of the flight, and a stepped or wandering edge reads as a hazard even when each nosing is technically flush.
Returning the stair to service
- Screw-fixed — immediately
- Adhesive — after full cure, typically 24 hours, longer in the cold
- Self-adhesive — 24 hours before heavy use
On a commercial stair, barrier the flight properly rather than relying on a sign. A part-fitted staircase is more dangerous than an unimproved one.
Ten mistakes that cause callbacks
- Cutting to the exact step width with no expansion clearance
- Bonding to a damp substrate
- Leaving old adhesive residue in place
- Over-tightening and cracking the profile at the countersink
- Using zinc-plated screws outdoors, which corrode and stain
- Too few fixings, leaving flex between screws
- No fixing near the ends, so a corner lifts
- Adhesive in dabs instead of continuous beads
- Walking on adhesive-fixed nosings before cure
- Fitting over a damaged edge instead of repairing it first
A note on compliance
If the stair is in a workplace or a public building, fitting is only half the job. Approved Document M sets a 55mm × 55mm contrasting band on tread and riser for buildings other than dwellings, and BS 8300-2:2018 recommends at least 30 points of Light Reflectance Value difference between the nosing and the tread. Choose the profile and colour with those in mind before you start cutting — it is an expensive thing to discover afterwards.
Frequently asked questions
How many screws does each stair nosing need?
Roughly 150mm centres on concrete and around 300mm on steel, with a minimum of three per step and always one near each end. Fewer fixings leave the profile free to flex between them, which loosens every screw in the run.
Can I fit stair nosings over existing carpet, vinyl or tile?
Yes, with the right profile. Carpet needs a profile designed to grip and retain the edge, tile needs a tile-in profile matched to the tile thickness, and LVT or laminate usually takes a push-in or slim surface-mounted profile. The covering changes both the profile depth and the fixing method.
Do I need to remove the old nosing first?
Usually yes. Fitting over a failing nosing stacks one problem on another. Remove old profiles with heat and a scraper rather than levering them off, which tears the substrate underneath and creates more making-good.
How long before I can walk on them?
Screw-fixed nosings are immediately serviceable. Adhesive needs the full cure, typically 24 hours at 20°C and longer when cold. Rushing this is the most common cause of a bond that fails months later.
What if my steps are all slightly different widths?
That is normal in older buildings. Measure and cut each one individually rather than batching to a single length. It takes longer but it is the difference between a flight that looks fitted and one that looks patched.
Can I install stair nosings in winter?
Mechanically, yes, at any temperature. Adhesive needs the substrate above about 5°C to cure properly, so for cold or external work choose screw fixing rather than trying to warm a whole flight.
Choosing the right profile
Fitting technique only works if the profile suits the job. Browse the full stair nosing range by material and profile shape, or narrow it down to aluminium profiles for general commercial and domestic work, or GRP for external, industrial and wash-down environments.
If you are unsure which profile fits your stair, send us the tread depth, the step width and what the stair is finished in, and we will specify against it.