Understanding Slip Ratings in Paving Projects
The first priority when specifying paving for any project should be to ensure the material is suitable for its intended use. When it comes to external paving, slip ratings are a critical factor — particularly for patios, paths, or seating areas where grip underfoot is essential.
A second consideration is the slope or gradient of the surface. Steeper walkways or inclined paths will require materials with greater grip to reduce the risk of slipping.
Most paving products are supplied with a slip rating, known as an ‘R’ rating. This rating indicates the level of slip resistance the surface provides. It’s based on the ramp test, where the higher the R value, the greater the friction and grip:
- R9: Low slip resistance – the least grippy and not recommended for external use
- R10: Moderate slip resistance – may be suitable for lighter use areas
- R11: Standard slip resistance – commonly used for general outdoor paving
- R12: High slip resistance – ideal for sloped or higher-traffic areas
- R13: Very high slip resistance – used in areas where maximum grip is needed
These ratings help ensure paving is safe and suitable for varying site conditions. If you’re specifying materials for areas near water — such as pool surrounds or wet room extensions — an additional rating may be used. Known as the ‘P’ rating, it’s determined using a wet pendulum test.
Slip ratings are also an important part of any project risk assessment, particularly for commercial or public spaces where safety and compliance are key.
