How to make shower tile less slippery

An earlier version of this article incorrectly used outdated information to define the desirable coefficient of friction for a tile shower floor. The old standard measured the static coefficient of friction, used before 2012. The new standard rates the dynamic coefficient of friction, which measures slip-resistance when something or someone is already in motion. For a level, wet surface, such as a shower floor, tile should have a dynamic coefficient of friction, often referred to as DCOF, of 0.42 or higher. The article has been corrected.

Q: We are both over 70 years old and want to avoid slipping and falling. We’ve installed grab bars in our shower, but it's completely tiled with shiny six-inch square tiles and the floor is slippery. We use a shower mat but because of the grout between the tiles, the mat does not stick very well and is not as safe as one would hope. Is there anything we can do to the tile floor to make it nonslip?

A: Slippery shower floors are a huge issue, so it's no surprise that manufacturers have come up with an array of possible solutions, including different types of mats, grip tape, and coatings and etching products.

Were you designing your shower from scratch, you could guard against slipping by choosing small tiles. The numerous grout lines would create a floor that's inherently slip-resistant. Or, if you wanted larger tiles, you could choose a style with a textured surface. The tile industry uses a rating system called the dynamic coefficient of friction, often listed as DCOF, which measures slip-resistance when someone or something is already in motion. For a shower, you’d want tiles with a DCOF of 0.42 or higher.

But you have six-inch tiles and they’re slippery. Mats are the simplest way to reduce the risk of slipping. As you have discovered, they don't always grip well. But there are styles that don't have suction cups, so one option would be to try a different type. Many mats are 16 or 17 inches wide, sized to fit in bathtubs. For a tiled shower, get one that covers more of the floor, such as the Tchdio non slip shower mat, which is 24 inches square ($21.99 on Amazon). The downside with any kind of mat is keeping it clean and free of mildew. It helps to hang it on a towel bar to dry, or, if your bathroom is big enough, on a clothes-drying rack or a quilt rack. West Elm's Yamazaki bath linen rack ($60) would be an elegant solution.

Beyond mats, options vary based partly on whether the tile was sealed, said Darren Merchant, sales supervisor for No Skidding Products. If the floor is sealed, he said, you’re limited to topical treatments, such as grip tape and coatings. If the floor is unsealed, you would also have the option of adding traction by using a penetrating sealer or an etching product. If you don't know whether the floor is sealed, Merchant suggested sprinkling some water on the floor when it is dry to see if the water soaks in and makes the color darker. A customer service representative for Miracle Sealants, which makes 511 anti-slip formula penetrating sealer ($17.99 a quart on Amazon), said the test for a product like 511 is to apply a small amount in a corner and see whether the solution soaks in.

Sealers and etching products have one big advantage: Unlike topical treatments, they can't peel. Sealers like the 511 formula make the surface harder and less likely to stain, which probably gives them an edge over etching products, which eat into the surface and thus may make cleaning more difficult. Sealers need to be reapplied periodically, which requires a thorough cleaning first, sometimes with acidic or other special products. Etching can clog with soap scum, which can make the floor as slippery as it is was before; scrubbing with a degreaser can restore the anti-slip surface.

No Skidding and SlipDoctors both offer etching treatments in containers much larger than what you would need to treat a single shower, but they also sell in smaller quantities designed for homeowners to use. No Skidding's D.I.Y. anti-slip bathtub treatment is $18.95 for a four-ounce bottle; the product is identical to what's in the gallon jugs sold for professionals to use. SlipDoctors’ Bathtub & shower kit ($35) comes with two one-ounce bottles, enough for one standard-size tub or shower. But this product is less aggressive than what is in the company's larger jugs, a company representative said. So the etching might wear off sooner, in a year or several years, and would then need to be redone.

If applying a sealer or etching the tiles isn't an option, consider grip tape, which usually comes in fairly narrow strips or rolls and works best in situations where the shower floor is smooth. For a tiled floor, you’d need to cut the strips to fit only on the tiles, skipping the grout lines. A better option would be a product such as Nadco anti-slip squares ($42.99 for a package of 50). These are 5½ inches square so you could center one on each tile and wind up with a relatively tidy look. A customer service representative for the manufacturer said they would work well in a shower. The adhesive is acrylic-based, so if the edges started to peel, which they almost certainly will at some point, you could use rubbing alcohol to remove them and start fresh. Color options are limited, though: black, white or yellow.

Or, instead of sticking on nonskid squares, you could roll, brush or spray a nonskid coating on the floor. Read labels to see how easy it would be to reapply the coating when it wears through or begins to peel.