A TECHNICAL GUIDE TO SLIP RATING FOR TILED FLOORS

When specifying tiles for an architectural project, aesthetic appeal must be balanced with technical performance, specifically slip resistance. This is particularly critical when aiming for a seamless transition between an interior kitchen and an exterior terrace.

To ensure the safety and longevity of your design, our studio utilises the following technical checklist . It is called the 'R' Rating (The Shod Ramp Test) and it is the most common classification for slip resistance. The values range from R9 to R13 indicating the degree of friction a tile provides.

• R9 Tiles: Provide a low level of friction. These are suitable for internal dry areas such as living rooms or hallways. They should not be used in areas prone to moisture.

• R10 Tiles: Offer moderate friction. These are often specified for internal domestic kitchens and bathrooms where occasional spills may occur.

• R11 Tiles: Provide high friction and are considered 'anti-slip'. This is the minimum standard we recommend for external terraces, patios, and walkways in the United Kingdom to ensure safety during wet weather.

• R12 & R13 Tiles: These offer the highest level of resistance and are typically reserved for commercial or industrial environments, such as professional kitchens or public swimming pool surrounds.

  
  

There is also The Pendulum Test Value (PTV):

In the United Kingdom, the Health and Safety Executive (HSE) often refers to the Pendulum Test. This is a rigorous test that mimics a heel striking a floor surface.

• For an area to be considered safe in wet conditions, it should achieve a minimum PTV of 36.

• When we specify tiles for a seamless indoor-outdoor transition, we ensure the external version of the tile meets or exceeds this 36+ PTV threshold.

  
  

Each of the above results in a surface finish. The texture that provides the grip (often achieved through a structured or "bussh-hammered" finish) can affect how the tile is maintained and hence it is a factor to be mindful of.

• Grip vs. Cleanability: Higher slip resistance often means a more textured surface. While this is essential for safety, it can trap more dirt. We advise our clients on the appropriate cleaning regimes to ensure their terrace remains pristine.

• Material Continuity: As mentioned in our previous post, many manufacturers now produce the same tile in two finishes: a smooth finish for the interior and a "grip" version for the exterior.

  
  

Additionally, and specially for exterior projects, we need to consider the environmental context.

London’s climate requires materials that can withstand the freeze cycle. It is not enough for a tile to be slip-resistant; it must also be frost-proof. Porcelain is a great material for this purpose due to its extremely low porosity, which prevents water from entering the tile and expanding when it freezes.

Final thoughts:

Selecting the incorrect slip rating can lead to significant safety risks and potential legal liabilities. This is why we do not provide uninformed opinions on material safety; instead, we rely on technical data sheets and expert consultations to ensure every architectural detail is fit for purpose.

Are you planning a project that requires a seamless transition from your home to your garden? Contact our studio for expert guidance on material specification and technical safety.