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Anti-Slip Ratings Explained: R9 to R13, PTV and Barefoot Classes
If you are choosing tiles or flooring for a bathroom or shower, you will see slip ratings like R10 or R11 and terms like PTV. They come from different tests and mean different things. This guide explains each one in plain English and which matters most for a bathroom floor.
What the R rating means
The R rating comes from a ramp test. A tester in safety shoes walks on a sample of the floor coated in oil while the ramp is tilted steeper and steeper. The angle at which they can no longer walk safely sets the rating.
| Rating | Ramp angle | Typical use |
|---|---|---|
| R9 | 6° – 10° | Mainly dry areas |
| R10 | Over 10° – 19° | Homes and areas with occasional moisture |
| R11 | Over 19° – 27° | Wetter areas, many outdoor tiles |
| R12 | Over 27° – 35° | Commercial kitchens and work areas |
| R13 | Over 35° | Heavily contaminated industrial floors |
A higher number is not automatically better for a home. Very high-grip surfaces can be harder to clean and uncomfortable underfoot.
Barefoot classes: A, B and C
Because the R test uses shoes and oil, it says little about wet, bare feet — which is exactly what happens in a shower. For that there is a separate barefoot ramp test, graded:
- Class A — 12° or more
- Class B — 18° or more
- Class C — 24° or more
For shower floors and wet rooms, look for a barefoot class on the manufacturer's data. B or C gives more grip where water collects.
PTV: the pendulum test
The pendulum test swings a rubber slider across the floor and gives a number called the Pendulum Test Value (PTV). It is widely used in the UK and can be done on a floor that is already laid. A wet PTV of 36 or above is the common benchmark for low slip potential.
R ratings and PTV come from different tests, so one cannot be converted into the other.
What to look for in a bathroom
- General bathroom floor: R10 is a sensible minimum for a domestic bathroom.
- Shower areas and wet rooms: check the barefoot class or the wet PTV, not just the R rating.
- Small tiles grip better than large ones in a shower, because the extra grout lines add texture.
- Safety vinyl is a reliable choice for wet rooms, with consistent grip across the whole floor.
- Anti-slip shower trays have a textured surface built in — a good option if you are keeping a tray.
Always use the slip data published by the manufacturer for the exact product you are buying.
Products in this guide
AKW Safety Flooring (0.5m x 2m) Cement 21901-CMT
£40.95
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Kartell K-VIT Anti-Slip Square Low Profile Shower Tray – All Sizes
From £112.50
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Nuie White Slip-Resistant Slimline Square Shower Tray (All Sizes)
From £144.00
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JT Fusion Anti-Slip Square Shower Tray 45mm – Gloss White with 90mm Waste – All Sizes
From £183.15
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Frequently asked questions
Is R10 good enough for a bathroom floor?
R10 is a sensible minimum for a domestic bathroom floor outside the shower. For shower areas, check the barefoot class or wet PTV as well.
Is R11 better than R10?
R11 grips more in the ramp test, but it is not always better for a home bathroom — it can feel rougher and be harder to clean. Choose the rating that suits the area.
What PTV is classed as low slip risk?
A wet PTV of 36 or above is widely used as the benchmark for low slip potential on level floors.