Slippery concrete steps are a genuine safety hazard, especially in New Zealand's wet winters and shaded, moss-prone conditions. The good news is there are several effective methods to add grip — from simple broom finishes on fresh concrete to anti-slip coatings and adhesive strips on existing steps — and many of them are well within a confident DIYer's reach.
Why Concrete Steps Become Slippery
New concrete that has been steel-trowelled to a smooth finish, or older concrete that has been polished by foot traffic, offers very little friction when wet. Add algae, moss, or a thin film of water and the surface becomes dangerously slick. In NZ, the NZ Building Code clause D1 (Access Routes) requires that pedestrian surfaces be slip-resistant, so addressing the problem isn't just sensible — it may be a compliance issue, particularly for rental properties under the Healthy Homes standards.
Method 1: Broom Finish (Best for Fresh or Resurfaced Concrete)
If you're pouring new concrete or applying a resurfacing compound, a broom finish is the simplest and most durable non-slip solution.
- After screeding and floating the concrete to a level surface, drag a stiff-bristled broom across the step in one smooth, consistent stroke.
- Work perpendicular to the direction of travel (across the width of the step, not front to back) so the ridges catch feet as they land.
- Allow the concrete to cure fully — at least 28 days — before applying any sealer.
- If sealing, choose a non-slip sealer or add a non-slip aggregate (fine sand or aluminium oxide) to the sealer before applying.
Resurfacing products from suppliers like Ardex or Mapei can give worn steps a fresh, grippy surface without a full replacement pour.
Method 2: Anti-Slip Coatings and Sealers (Best for Existing Steps)
For existing concrete steps, a textured anti-slip coating is one of the most popular DIY options.
What to look for
- Coatings that contain fine aggregate (sand, aluminium oxide, or rubber granules) mixed in, or that you broadcast onto a wet coat.
- Products rated for exterior, wet-area use.
- UV-stable formulas if the steps are exposed to direct sun.
Application steps
- Clean thoroughly — remove all dirt, moss, algae, oil, and loose material. A pressure washer works well; follow up with a diluted bleach solution for biological growth, then rinse and allow to dry completely.
- Repair cracks and spalls first using a suitable concrete repair mortar.
- Apply the coating with a roller or brush, following the manufacturer's dwell times between coats.
- On the final coat, you can broadcast additional fine sand or aluminium oxide grit while the coating is still wet for extra texture, then lightly roll it in.
Check the paint and coatings ranges at Resene, Dulux, or Wattyl — all carry exterior concrete coatings suitable for steps. Your local Bunnings or Mitre 10 store will also stock anti-slip additives you can mix into most sealers.
Method 3: Anti-Slip Grip Strips and Nosing Inserts
Adhesive grip strips or aluminium nosing inserts are a fast, low-skill solution — ideal for rental properties or when you need a quick fix.
| Option | Pros | Cons |
|---|---|---|
| Adhesive grip tape | Cheap, fast, no tools | Can peel over time, needs replacing |
| Aluminium nosing with grip insert | Very durable, tidy look | Requires drilling, higher cost |
| Rubber stair nosing | Good grip, cushioned | Can trap moisture underneath |
- For adhesive strips, clean and dry the surface thoroughly before application — any moisture or dust will cause premature lifting.
- Aluminium nosing profiles are fixed with masonry anchors drilled into the step edge. These are available at PlaceMakers and most hardware stores.
- Check that any nosing profile meets applicable accessibility requirements if the steps serve a public or shared area — confirm the relevant standard with your council or a professional.
Method 4: Exposed Aggregate Finish
If you're replacing or pouring new steps, an exposed aggregate finish provides excellent long-term grip and looks great. After pouring, a surface retarder is applied, and once the concrete has partially set, the top layer is washed away to reveal the aggregate beneath. This is a technique best left to an experienced concreter as timing is critical.
Maintenance Tips
- Clean steps regularly to prevent algae and moss build-up — these are the number one cause of slippery steps in NZ.
- Reapply coatings or grip tape as needed; most coatings will need a refresh every few years depending on traffic and UV exposure.
- Trim back overhanging plants that keep steps in permanent shade and damp.
When to Call a Professional
While cleaning, coating, and applying grip strips are all DIY-friendly tasks, there are situations where you should bring in a qualified concreter or Licensed Building Practitioner (LBP):
- If the steps are structurally cracked, sunken, or heaving — surface treatments won't fix underlying problems.
- If you're replacing or rebuilding steps that are attached to the house structure, a building consent may be required. Always check with your local council, as Schedule 1 exemptions have specific conditions. See MBIE Building Performance for guidance.
- If steps serve a commercial or public building, compliance with accessibility standards (NZS 4121) and the Building Code must be verified by a professional.
- For large-scale resurfacing or exposed aggregate work where timing and mix ratios are critical.
You can find qualified local concreters and building tradespeople on tradedirectory.co.nz.
Safety note: Always wear gloves, eye protection, and a dust mask when working with concrete products, sealers, and coatings. Check the Safety Data Sheet (SDS) for any product you use. See WorkSafe NZ for guidance on safe handling of construction chemicals.
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