While slip-resistant tiles are mandatory in public and commercial areas, there is no obligation whatsoever for the private sector. However, why you should also pay attention to the slip resistance of your tiles in your own four walls and how you can ensure the necessary slip resistance, you will find out in the following article.

Watch out, danger of slipping!

Universally applicable and hard-wearing, yet at the same time visually appealing and easy to clean: a floor covering made of tiles offers many undisputed advantages. If it weren’t for this small but sometimes momentous downer.

Tiles can quickly become quite smooth in wet or damp conditions. This is because water, grease and dirt significantly reduce the static friction coefficient of the surface. Especially in the bathroom, around the pool, on the terrace or even in the kitchen, one wrong step is often enough to lose your footing.

This is not only annoying, but above all can be dangerous. According to accident statistics, insufficiently slip-resistant floors are one of the most frequent causes of falls and injuries. A good reason, therefore, to attach importance to sufficient safety in areas with increased risk of slipping.

Non-slip tile: That’s what counts

Although slip-resistant tiles are not a must in the private sector, they are the best prevention against accidents. It is therefore best to pay attention to the slip resistance of tiles as early as the planning and purchasing decision.

Material and format

The material or the structure of the surface already gives a first visible hint. In general, the rule is: the rougher a tile is, the higher the slip resistance. For example, untreated natural stone or porcelain stoneware tiles are inherently relatively slip-resistant, while glazed, impregnated or high-gloss polished tiles are generally less able to meet the requirements.

The size of the tiles also has an influence on slip resistance: with smaller formats, the proportion of joints on the floor surface is higher – and this also has a positive effect on slip resistance. This is one of the reasons why mosaic tiles are often used, especially in areas with an increased amount of water (e.g. showers or swimming pools), as the many joints give the floor a kind of braking effect.

Anti-slip classes according to DIN standard

However, it is not possible to determine at a glance how slip-resistant the tile actually is. Much more decisive is therefore the marking based on standardised slip resistance classes. However, these have nothing in common with the tile abrasion group.

Although these are primarily important for compliance with the legal requirements for non-slip tiles in the commercial or public sector, they naturally also offer private consumers a reliable guide to help them choose the right tiles.

Assessment of slip resistance: Tiles in test procedure

As with any other floor covering, the assessment of the slip resistance of tiles is carried out according to a special procedure: the so-called walk on sloping ground. In order to determine the static friction coefficient of the tiles, an expert test person from the tile manufacturer walks back and forth on the surface to be tested, whereby the angle of inclination of the tile is increased more and more by lifting it to one side. Depending on the commercial sector in which the floor covering is to be used, the test is carried out either with footwear on oil or barefoot on water, in order to simulate as real a use as possible. As soon as the test person begins to slip or become unsteady on the prepared surface, the test ends.

Classification according to evaluation groups

Based on these results, slip-resistant tiles are now assigned to the corresponding evaluation groups R9 to R13 according to DIN standard 51130 as follows

Class R9:

low coefficient of static friction, safe to step on at an angle of inclination of 6 – 10°, suitable for e.g. living rooms, interior stairs, entrance areas etc.

Class R10:

normal coefficient of static friction, safe to step on at an angle of inclination of 11 – 19°, suitable for e.g. outdoor stairs or tiles in outdoor areas, bathrooms, balconies / terraces etc.

Class R11:

increased coefficient of static friction, safe to step on at an angle of inclination of 20 – 27°; suitable for e.g. outdoor installations,

Class R12:

high coefficient of static friction, safe to step on at an angle of inclination of 28 – 35°, suitable for e.g. cold stores, hospitals, canteen kitchens

Class R13:

very high coefficient of static friction, safe to step on at an angle of inclination of over 35°, suitable for e.g. workshops, slaughterhouses, production halls etc.

If the floor covering is also suitable for use in so-called wet barefoot areas according to DIN 51097, an additional value is added to the tiles:

Class A:

very low slip resistance, slip resistance up to an angle of inclination of 12°, suitable for dry to maximum wet floors

Class B:

medium slip resistance, slip resistance up to an angle of inclination of 18°, suitable for wet floors

Class C:

high slip resistance, sure-footed up to an angle of inclination of 24°, suitable for swimming pools

What slip resistance tiles need in private homes

Depending on the slip class to which tiles are assigned, this results in the possible areas of application. However, it must always be kept in mind that the evaluation groups apply primarily in the commercial sector – and there the requirements for tile slip resistance are much higher than in private use. In addition, with tiles of higher slip-resistance classes, the cleaning effort also increases because the surface is rougher. The motto with regard to surefootedness at home is therefore: less is often more.

For normal domestic use, therefore, tiles of the R9 and R10 rating groups are usually laid. Even their “low” to “normal” coefficient of static friction usually meets the requirements for adequate slip resistance completely without the floor covering losing its attractiveness and comfort.

In sanitary rooms or outdoor areas, a higher degree of slip resistance can be achieved, if required, by using rating groups “B” or “C” and with tiles R10 and R11. Especially if people often walk barefoot there, this can of course be highly recommended. Class R12 and R13 tiles, on the other hand, are basically designed for special, mostly industrial areas and are therefore no longer relevant for private use.

Making smooth tiles non-slip

Ideally, the slip resistance is therefore already taken into account during the planning or laying phase. But even if it only turns out afterwards that certain areas are too slippery, this does not necessarily mean that the leg is broken. After all, even in retrospect there are various methods of improving slip resistance:

  • A simple but very effective option are self-adhesive anti-slip strips. These are simply stuck onto the smooth areas at specific points and thus provide more grip. They are particularly suitable for stair steps, but can also be used in wet areas.
  • In order to increase the slip resistance on larger surfaces, adhesive coverings and foils are suitable, which can also be applied relatively easily.
  • In addition, there are special anti-slip coatings or varnishes with which the entire surface can be provided.
  • Another possibility is to treat the tiles mechanically (e.g. by sandblasting or compressed air technology), chemically (e.g. fluorine, chlorine or ammonium compounds) or with laser technology and thereby additionally roughen the surface.