Car Parks: The Overlooked Slip Risk in Commercial Properties

External and undercover car parks are becoming a higher priority for facility managers, insurers and asset owners.

They are not just vehicle areas. They are pedestrian environments, often used by customers, tenants, staff, contractors and cleaners every day. Yet they are frequently treated as secondary spaces when it comes to cleaning, inspection and slip resistance management.

That creates risk.

Car parks often contain a mix of concrete, painted line markings, traffic coatings, pedestrian crossings, ramps, drains and transition areas. Over time, these surfaces wear unevenly. Some areas remain textured. Others become polished, contaminated or coated with materials that no longer perform as originally intended.

Why car parks need closer attention

Slip risk in car parks is rarely caused by one factor alone. It usually comes from a combination of:

• worn paint or line markings
• ageing traffic coatings
• inconsistent resurfacing or patch repairs
• oil, tyre residue, dust and water contamination
• sloped or ramped pedestrian paths
• reduced cleaning attention in car parks and back-of-house areas
• poor drainage or moisture tracking from vehicles

AS 4586:2013 makes clear that usage, cleaning systems, applied coatings and wear patterns can affect slip resistance after classification. It also notes that specifiers should consider in-service wear, traffic, environmental conditions, cleaning and sealing when selecting surfaces.

Undercover does not mean low risk

Undercover car parks can be misunderstood because they are partially protected from rain. But they are not necessarily dry, clean or consistent.

Water can still enter from vehicles, wind-driven rain, leaks, mopping, drainage issues or pedestrian movement from external areas. Contaminants can also build up over time, particularly where cleaning is irregular.

HB 198:2014 guidance identifies undercover car parks as requiring a P3 wet pendulum classification, while external car park areas, pedestrian crossings, external ramps and sloping driveways may require higher classifications depending on the location and conditions.

The cleaning issue

When cleaning hours are reduced, car parks and back-of-house areas are often the first to suffer.

That matters because these areas collect contaminants that are not always visible, including tyre residue, oils, fine dirt, water and detergent build-up. A surface may look acceptable while its slip resistance has changed materially.

This is where asset teams and cleaning teams can miss the risk. Cleanliness is often judged visually. Slip resistance is not visual. It has to be measured.

Painted markings and coatings need attention

Painted pedestrian crossings, directional markings and traffic coatings can create localised slip risk, especially where they are worn, smooth, contaminated or installed on sloped sections.

Many sites also contain a patchwork of coating systems applied at different times. Older coatings, newer repairs and worn markings may all perform differently underfoot.

That inconsistency can matter in a claim, because a pedestrian does not experience the car park as one uniform surface. They experience the specific patch of floor they step on.

What should facility managers do?

Car parks should be included in routine pedestrian surface risk reviews, particularly where there are:

• pedestrian crossings through vehicle zones
• ramps or sloped walkways
• undercover entries and exits
• painted or coated pedestrian paths
• recurring water or contamination issues
• recent resurfacing, repainting or coating works
• prior slip incidents or complaints

Testing existing pedestrian surfaces to AS 4663:2013 provides objective data about how the surface is performing in its current condition. Where interpretation is required, results can be assessed against relevant guidance, including HB 198:2014 and AS 4586:2013 classifications.

The practical takeaway

Car parks are often managed as operational zones, not pedestrian risk zones.

That needs to change.

For many commercial properties, car parks are now one of the areas where surface wear, contamination, coatings, cleaning and slope come together. If these areas are not tested and monitored, risk can increase quietly over time.

Visual inspection is not enough.

If a car park surface is used by pedestrians, exposed to moisture or contamination, or includes painted markings, ramps or coatings, it should be assessed as part of the site’s slip risk management program.

Zerofal provides on-site slip resistance testing for existing pedestrian surfaces, including external and undercover car parks, ramps, crossings and back-of-house areas.