Concrete steps are among the most dangerous surfaces in any property. Falls on steps account for a significant proportion of home injury hospitalisations across Australia, and wet, smooth concrete steps are a major contributing factor. On the Central Coast, where steps are frequently wet from morning dew, sea spray, or rain, and where algae and moss grow rapidly in the humid coastal climate, maintaining adequate slip resistance on outdoor steps is both a safety and a liability priority.
This guide explains how slip resistance is measured, what the standards require, and how to choose the right sealer or coating for your specific steps.
How Slip Resistance Is Measured
In Australia, the primary test method for outdoor surfaces is the Pendulum Test Method (described in AS 4586). The result is expressed as a Pendulum Test Value (PTV):
| PTV Range | Classification | Risk Level |
|---|---|---|
| 0-24 | P0 | Unacceptable, high slip risk |
| 25-35 | P1, P2 | Marginal, only acceptable in dry areas |
| 36-44 | P3 | Acceptable for dry external areas |
| 45-54 | P4 | Acceptable for most wet external areas |
| ≥55 | P5 | Required for high-risk wet areas (pool surrounds, ramps) |
The key point for steps: A concrete step surface that feels rough when dry may have a wet PTV under 36, particularly if it has a topical sealer coating that creates a film over the surface texture. Film-forming sealers (acrylics, some polyurethanes) reduce wet slip resistance by providing a smooth film that water planes over.
What the Standards Require
AS 1428.1 (Design for Access and Mobility): For steps in a public path of travel, minimum P4 (PTV ≥ 45) in wet conditions is required on the step tread.
Building Code of Australia / NCC: For steps in commercial premises and residential Class 1b or Class 2-9 buildings, the NCC requires step treads to be slip-resistant under AS 4586. For private residences (Class 1a), there is no legislated standard, but the common law duty of care to visitors still applies.
Pool safety standards (AS/NZS 1926.1): Steps in pool surrounds must meet a minimum of P4 (PTV ≥ 45 wet), which is more stringent than general outdoor requirements. Many pool area steps fail this test and are not in compliance.
Why Coastal Steps Lose Slip Resistance Faster
On the Central Coast, outdoor concrete steps deteriorate in slip resistance faster than in non-coastal environments for several reasons:
Algae and lichen growth: The warm, humid climate supports rapid biological growth on concrete. A thin layer of algae on a step surface drops the wet PTV dramatically, from P4 to P1 or lower. Steps that are shaded (north sides of buildings, beneath tree canopy) are particularly susceptible.
Salt air sealer degradation: UV-stable sealers in coastal environments still degrade faster than in sheltered inland locations. As the sealer degrades, it may become rough (holding more aggregate = higher PTV) or smooth (sealer is polished off = lower PTV) depending on the failure mode.
Thermal cycling: The Central Coast’s temperature range (5°C winter nights, 38°C+ summer afternoons) creates repeated thermal expansion and contraction that micro-fractures coating surfaces over time, eventually producing a texture that holds water rather than shedding it.
Hose-down and foot polish: Steps that are regularly hosed down and walked on (particularly bare-foot on pool steps) gradually polish the surface of any coating over time, reducing PTV.
Types of Slip-Resistant Products
1. Penetrating Impregnating Sealer (No Slip Additive)
Penetrating sealers soak into the concrete and don’t form a film on the surface. They don’t significantly change the surface texture and therefore don’t reduce the slip resistance of the underlying concrete, but they also don’t improve it. If the underlying concrete has a rough enough texture to achieve the required PTV, a penetrating sealer maintains that without reducing it.
Best for: Steps with adequate existing texture (broom finish, exposed aggregate) where you want to protect the concrete without changing its appearance.
2. Topical Sealer with Non-Slip Additive
Most topical sealers (acrylic, polyurethane) reduce the wet PTV of the surface they’re applied to. To counteract this, non-slip additives are incorporated into the final coat:
- Aluminium oxide: Tiny particles of very hard aluminium oxide suspended in the sealer. Creates a permanent abrasive surface. Available in fine (barely visible) and coarse (clearly visible grip texture) grades.
- Quartz sand: Similar to aluminium oxide but less hard. More cosmetically subtle.
- Shark Grip / similar products: Pre-mixed non-slip additives with specific particle sizes calibrated to achieve P3, P5 ratings.
The particle size and density determine the PTV achieved. For steps requiring P4 (PTV ≥ 45), a medium aluminium oxide loading in the final coat is typically sufficient.
Best for: Steps that need a topical sealer for colour protection or appearance, where non-slip performance must be maintained.
3. Anti-Slip Paint / Coating
Purpose-formulated anti-slip coatings for concrete steps. These are pre-loaded with non-slip aggregate and applied in one or two coats directly to prepared concrete. Less flexible in colour choice but simpler to apply than a separate sealer + additive.
Best for: Simple, cost-effective step safety treatments where appearance is secondary.
4. Applied Grit Strips
Self-adhesive anti-slip grit strips (GRP, aluminium or abrasive paper-faced) can be applied to the leading edge of step treads. These are a quick fix for immediate compliance but are not as durable as an applied coating, they peel at the edges, collect dirt, and require annual replacement in coastal conditions.
Best for: Temporary or emergency compliance where a full coating application isn’t immediately possible.
5. Mechanically Applied Texture
For concrete steps with very smooth surfaces (hand-trowelled, or polished), mechanical texture can be added before sealing:
- Diamond grinding in a crosshatch pattern
- Scabbling or bush-hammering the step tread
- Sandblasting
These physical interventions improve the underlying concrete texture, after which any sealer system (with or without additive) will achieve higher PTV.
Application Guide
Step 1: Clean and Prepare the Surface
- Pressure wash with water (minimum 1,500 PSI) to remove dirt, algae, and loose material
- Apply a 3% bleach solution or dedicated concrete anti-algae treatment to any organic growth, allow 15 minutes dwell, rinse thoroughly
- Allow to dry completely (minimum 48 hours, longer in humid conditions)
Step 2: Check Sealer Condition
If steps have an existing sealer, check its condition:
- If the sealer is sound and adhered, the new non-slip coat can go over it (surface clean and lightly abraded)
- If the sealer is peeling or flaking, it must be completely removed before any new product is applied
Step 3: Apply Primer (If Required)
For bare concrete or after sealer removal, apply the appropriate primer for your coating system. For small step areas, a penetrating primer or diluted first coat often serves as the primer. Follow the product manufacturer’s datasheet.
Step 4: Apply Non-Slip Coat
Apply the sealer coat with non-slip additive. For step applications:
- Brush application gives better control around edges and nosings than roller
- Apply a slightly thicker coat on the tread face to maximise additive density
- Pay special attention to the step nosing (leading edge), this is where most falls initiate
Step 5: Verify Performance
If you need documented PTV for commercial premises or body corporate areas, arrange a Pendulum Test after curing (typically at 7 days cure minimum). A NATA-accredited testing laboratory provides a test report that is acceptable for compliance documentation.
Cost Guide for Step Sealing on the Central Coast
| Step Area | Scope | Typical Cost |
|---|---|---|
| 1-5 steps (standard residential) | Clean + non-slip coat | $180 to $400 |
| 6-10 steps | Clean + prep + non-slip coat | $350 to $650 |
| Full step flight (12-20 steps) | Full preparation and coating | $550 to $1,200 |
| Commercial step set (with test report) | Full system + PTV test | $800 to $2,000 |
Note: Minimum call-out charges typically apply for small areas. Combining step sealing with a larger project (driveway resurfacing, path sealing) is more cost-effective.
Frequently Asked Questions
My steps are painted, can I just add non-slip additive to the paint? Not reliably. If the paint is in good condition, you can apply a specific non-slip coating over it with proper surface preparation. But if the paint is flaking or peeling, no topcoat will adhere reliably, the paint must come off first.
Can you make my steps match my driveway colour after applying non-slip coating? Yes. Non-slip coatings are available in a range of colours and can be matched to the adjacent surface reasonably closely. Exact colour matching to existing concrete is difficult (see our colour matching guide) but within the same colour family is achievable.
How long does a non-slip coating last on outdoor steps? In a Central Coast coastal environment, a quality polyurethane non-slip coating on steps lasts 4-8 years before re-application is needed. Annual inspection and cleaning is recommended, if algae is returning quickly or the surface starts to look worn, re-application is approaching.
Can you re-apply non-slip coating without stripping the old coat? If the existing coat is sound and well-adhered, a new coat can go over it after proper cleaning and light abrasion. If the old coat is peeling, it must be removed first. Each application cycle adds thickness, after 3-4 cycles, the coating may need to be fully stripped and re-started.
My elderly parents live in Gosford and their back steps are very slippery, how soon can you help? This is exactly the kind of job we prioritise. Contact us for a fast assessment and we can typically complete step sealing within a week of initial contact. For urgent safety situations involving elderly occupants or disability access, mention this when you enquire.
Don’t wait for a fall. Get a free assessment of your steps and paths, we check slip resistance, recommend the right treatment, and get the work done quickly.