How is slip resistance specified on a public walkway?

Slips are the most common injury on public and school sites, and they concentrate in predictable places: ramps, external stairs, entries where water is tracked in, and any surface that was selected for its appearance.

Slip resistance is a measured classification

Surfaces carry a slip resistance rating from a defined test, and the required rating depends on the location: a dry internal corridor, a wet external ramp and an entry where water gets tracked in are three different requirements.

Which means the specification references the classification and the test, not a description. A tile that looks textured can perform poorly wet, and a surface that performs well new can fall below the requirement once it is worn or polished by cleaning.

The classification is also the thing a certifier and an insurer will ask about, which is why the test certificates go into the handover record described in [handover documentation and operation manuals](/answers/handover-documentation-and-operation-manuals).

Where the problems are

**External ramps,** where the gradient and the water combine. The highest risk surface on most sites and the one most often specified as a continuation of the adjacent paving. The access requirements for them are in [how are accessible ramps and chair lifts installed for disability access](/answers/how-are-accessible-ramps-and-chair-lifts-installed-for-disability-acce).

**External stairs,** where the nosing is the critical element and where the contrast requirement sits alongside the slip requirement.

**Building entries,** because water tracked in produces a wet surface on a floor specified as dry. The fix is usually a matting zone of sufficient length rather than a different floor.

**Amenities,** where the floor is wet by design, which is part of [how are school toilet and amenity blocks upgraded to the new NSW facilities guidelines](/answers/how-are-school-toilet-and-amenity-blocks-upgraded-to-the-new-nsw-facil).

**Painted surfaces,** including line marking and court coatings, which can be substantially more slippery than the substrate underneath. The additive goes in the specification rather than being assumed, and it matters most on the markings covered in [line marking and play markings](/answers/line-marking-and-play-markings).

**Timber decks and boardwalks,** which become slippery with algae growth in shaded positions, which is the maintenance consideration in [boardwalks and timber structures](/answers/boardwalks-and-timber-structures).

Treating an existing surface

Replacement is not always warranted, and there are options that work.

**Chemical etching,** which micro-textures the surface of a tile or a stone and raises the rating without changing its appearance. Effective, and it has a service life rather than being permanent.

**Anti-slip coatings,** applied over a prepared surface, which work well where the appearance can change.

**Mechanical texturing,** grinding or shot blasting a concrete surface, which is durable and visible.

**Anti-slip inserts and nosing strips,** which address the specific hazard at a stair edge rather than the whole surface.

**Mechanical grinding of a lip or a high point,** where the real hazard is a trip rather than a slip.

The right answer depends on the substrate, the exposure and how long the asset is expected to last. On a surface approaching the end of its life, replacement is usually the better outcome, which is the calculation in [flooring replacement in an operating building](/answers/flooring-replacement-in-an-operating-building).

Cleaning changes the performance

A surface specified correctly can be made hazardous by the wrong cleaning regime: a polish applied over a textured floor, or a detergent that leaves a film.

Which is why the cleaning requirements for a specified surface are handed over with the building rather than left to be worked out, and why a slip problem in a recently completed building is as often a cleaning issue as a specification one.

Testing after installation

The useful check is a test on the installed surface rather than on a sample, because the installation method and the grout or joint pattern affect the result.

On a ramp, an entry or an amenity floor, that test is worth having in the record. It is also the only way to answer the question when somebody asks later whether the surface met the requirement when it was built.

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