Anti-skid tiles: what R10 and R11 mean
R9 to R13 is a slip rating measured on a ramp under DIN 51130. For a home: R10 indoors where it gets wet, R11 anywhere the rain reaches.
What the rating measures
A tester walks an oiled tile on a ramp that tilts until they slip. The angle at which that happens sets the class:
| Class | Ramp angle | In practice |
|---|---|---|
| R9 | 6–10° | Dry indoor floors — bedrooms, living rooms |
| R10 | 10–19° | Kitchens, bathrooms, entrances |
| R11 | 19–27° | Balconies, terraces, open passages, garages |
| R12–R13 | 27°+ | Commercial kitchens, industrial floors, ramps |
There is a second standard, DIN 51097, for barefoot wet areas, graded A, B and C. A shower floor rated B or C is graded for the way it will actually be used: wet, soapy, and without shoes.
What to buy, room by room
- Bathroom floor — R10 minimum, and B or C if the rating is quoted. Small formats also help: more grout lines is more grip.
- Kitchen floor — R10. Oil underfoot is a harder problem than water.
- Balcony, terrace, open passage — R11. This is a Mumbai answer as much as a technical one: for four months a year those floors are wet with driving rain and nobody is wearing shoes.
- Bedrooms, living rooms, dry passages — R9 is fine. Do not pay for grip you will only have to scrub.
The trade-off nobody mentions
Grip is texture, and texture holds dirt. An R11 floor is a rougher floor: it takes more effort to mop and it will not look glassy. That is the correct trade outdoors and the wrong one in a living room. Buy the rating the room needs and no more.
What grip does not fix
Anti-skid tile reduces the chance of a slip; it does not eliminate it, and it cannot compensate for water that has nowhere to drain. Get the fall towards the drain right, keep the floor free of soap film, and treat the rating as the last line of defence rather than the first.