Hot Tub Tiles: Mosaics, Porcelain vs Ceramic, Slip Resistance and Grout

Updated September 2026. I’ve rewritten this guide with what I’ve learned from helping more than 1,500 people build their own tubs. I’ve added mosaic pool tiles, the real difference between porcelain and ceramic, slip resistance for steps and seats, and the adhesive and grout that should go behind them.

Tiles are the perfect way to finish a DIY hot tub. I’ve always thought tubs look best finished in tile. Yes, tile costs more than a painted finish, but in my humble opinion it’s well worth it. It’s hard-wearing, easy to keep clean, and it’s what you’ll be looking at every time you get in.

Not every tile is suitable, though. A hot tub is warm, chemically treated water, all day, every day, with bare feet on the steps and seats. This guide covers which tiles work, which to avoid, and what goes behind them.

What tiles can I use on a hot tub?

When you’re choosing tiles for a tub, think about four things: what the tile is made of, how much water it absorbs, how slippery it is when wet, and how well it copes with heat, chemicals and (outside) frost. Here’s how the main options compare:

Tile type	Under water?	Good for	Watch out for
Glass mosaic	Yes, if sold as pool tile	Walls, seats, curves. Colours that shimmer under water and don’t fade.	Smooth glass is slippery. Use the anti-slip version on steps and floors.
Porcelain mosaic	Yes	Everywhere, including textured anti-slip versions for floors and steps	Check that it’s rated for pools and, outdoors, for frost
Larger porcelain tiles	Yes, on flat areas	Flat walls and floors in a modern, square design	Won’t follow curves. Needs a very flat surface and more care with movement.
Ordinary ceramic (wall tile)	Not recommended	Above the water in a sheltered or indoor spot	More absorbent body. Can craze, stain or crack in frost.
Natural stone	Generally no	Coping and surrounds, if the stone is suitable	Porous, and it can stain or etch. Needs sealing and the right stone.

The simple rule: if the tile manufacturer doesn’t say it’s suitable for swimming pools, don’t put it under water. “Suitable for wet rooms” isn’t the same thing.

Why I’d choose mosaic pool tiles

Hot tub tiles come in small mosaic sizes and larger rectangular sizes. When I first wrote this post, I sat on the fence about which to use. Having now seen so many customer builds, I’ll be straight with you: I’d go for mosaic pool tiles every time. I used larger tiles on my own tub, and it’s one of the things I’d change if I did it again. I’ve written more about that in What I’d change if I built my DIY hot tub again.

Here’s why mosaics suit a hot tub so well:

• They follow the shape. A hot tub is all seats, steps, corners and sometimes curves. Mosaics come on a mesh or paper sheet, so they wrap round radiused edges and bullnoses. Big tiles need cutting at every change of plane.
• They cope with movement. Lots of small tiles and lots of grout joints spread any movement from heating and cooling. Large tiles crack more easily and are harder to repair or replace.
• More grip. All those grout joints give your feet something to hold, especially on the seats.
• They forgive a less-than-perfect surface better than a big format tile, although you still want the render flat.
• That look. Glass mosaic under warm, lit water is in a different league.

The trade-off is more grout lines to keep clean. With an epoxy grout and balanced water, that’s not the chore it sounds.

Porcelain vs ceramic: what’s the difference?

Both are fired clay tiles, but they’re not the same:

• Ceramic tiles are made from clay and other natural materials such as sand and feldspar, then fired in a kiln. The body is relatively porous, so they rely on a glaze to stop water and stains.
• Porcelain tiles are made from more refined clays and fired at a higher temperature, which makes them much denser. Under the international and European tile standards (ISO 13006 and BS EN 14411), porcelain is defined by water absorption of less than 0.5%.

Why does that number matter in a hot tub? A tile that soaks up water can let chemicals and minerals into the body of the tile, can stain, and outdoors can crack when that water freezes. Porcelain’s very low absorption is why porcelain (and glass, which absorbs next to nothing) is the go-to for pools. Ordinary glazed ceramic wall tiles are fine in a bathroom. Under 40°C chlorinated water all year, and through a British or North American winter, they’re a gamble.

Porcelain does cost a bit more than basic ceramic, but on a hot tub-sized area the difference is small compared with the cost of retiling.

What about glass tiles?

Glass mosaics are hugely popular for hot tubs, and for good reason. The colours shimmer under water, they don’t fade, and glass is non-porous. Two things to know. First, smooth glass is slippery when wet, so use the textured anti-slip versions on steps and floors. Second, some manufacturers want a specific adhesive for submerged glass tile. In the USA, for example, Ardex specifies its WA epoxy for glass tile under water. Check the tile maker’s instructions.

Slip resistance for steps and seats

This was missing from my original post, and it matters. Everyone gets in and out of a hot tub on wet, bare feet, often in the dark, sometimes after a glass of something. The steps and the floor are where people slip.

• Use anti-slip tiles where people stand. Most pool mosaic ranges include a textured or anti-slip version for steps, benches and shallow floors. Keep the smooth, glossy tiles for the walls.
• Ask for the barefoot rating. Pool tile makers often quote a barefoot slip rating (in Europe this is usually the German DIN 51097 classes A, B and C, with C the grippiest). For steps into the water, ask for the highest class they offer.
• Understand the UK test. In the UK, the HSE uses the pendulum test. Its guidance on assessing slip resistance classes a Pendulum Test Value (PTV) of 36 or more as “low slip potential”, and uses a softer rubber slider (Slider 55) for barefoot areas. If a tile quotes a wet PTV of 36+, that’s a good sign.
• Mark the edges. A contrasting tile along the front edge of each step makes the step visible, day and night. Underwater lighting helps too. See my guide to underwater hot tub lighting.
• Don’t forget the surround. The coping and deck around the tub get wet feet too. Choose an outdoor-rated, textured surface.

For step layout, riser heights and handrails, see Hot tub steps: the ultimate guide.

Colour and design

Colour is personal, but a few things are worth knowing. Lighter blues and whites make the water look clear and inviting, but show dirt and scale lines more. Darker tiles look dramatic and hide marks better. Many people run a band of feature tiles along the waterline, where scale and body oils collect, so it’s easier to wipe clean. Think about the setting too. You may want tiles that tie in with your garden, deck and house, or a bold contrast.

Swimming pool grade adhesive and grout

Whatever tile you choose, it’s only as good as what’s behind it. The adhesive and grout must be swimming pool grade, not the standard stuff for floors, walls and worktops. Here’s the difference:

	Standard adhesive and grout	Swimming pool grade
Designed for	Kitchens, bathrooms, floors	Permanent immersion in treated water
Adhesive	Often a basic C1 cement adhesive	Improved, flexible cement adhesive (C2 class or better) or a reaction resin
Grout	Standard cement grout, which can wash out	Epoxy (class RG), or a pool-rated polymer cement grout
Chemical resistance	Limited	Made to cope with sanitisers and water chemistry

As an example, the pool mosaic maker Ezarri’s installation guide recommends an adhesive of at least C2TE classification on concrete, and epoxy grouts classified RG.

Why epoxy grout? Warm, soft or low-pH water attacks cement-based grout. The Tile & Stone Journal notes that aggressive water “dissolves calcium salts in cement-based grouts, leading to erosion and loss of bond”, and strongly advises epoxy where calcium is below 250mg per litre. A hot tub is exactly that environment, so epoxy is my recommendation.

And remember, tiles and grout aren’t the waterproofing. They go on top of a pool-rated membrane that’s been flood tested. I’ve covered the membrane, the adhesive and grout products, and the cure times before you fill in Waterproofing, grout and tile adhesive.

Tiling tips

• Get the surface flat first. Mosaics show every lump in the render.
• Full coverage, no voids. Under water, a hollow spot behind a tile is a weak spot. Use the right notched trowel and press the sheets in firmly. Back-butter larger tiles.
• Plan the setting out so cut pieces end up in corners and under the waterline, not on the front of the steps.
• Clean epoxy grout off as you go. You have a short window before it sets on the tile face.
• Leave movement joints where the tile meets different materials and at changes of plane, as your adhesive maker specifies.
• Let everything cure before you fill. It’s usually days, not hours. Check the data sheets.

Common problems and what causes them

Problem	Likely cause	What to do
Grout washing out or going sandy	Cement grout in soft or low-pH water	Balance the water. Regrout in epoxy.
White crust on the waterline	Scale from high pH or hard water	Bring pH and alkalinity into range, and use a tile cleaner made for pools
Tiles sounding hollow or falling off	Voids in the adhesive, the wrong adhesive, or filling too soon	Drain, remove, and refix with pool-grade adhesive at full coverage
Cracked tiles	Movement in large tiles, frost, or no movement joints	Replace with mosaic if you can, and add movement joints
Slippery steps	Smooth glass or glazed tile underfoot	Retile the treads with anti-slip mosaic

Most of these are water chemistry. For a tiled tub, keep calcium hardness around 200–400 ppm and pH at 7.2–7.6. My hot tub chemical levels guide has the full ranges. If you ever need to drain down for tile repairs, see How to drain and clean a hot tub.

Tiles or a liner?

Tile isn’t the only finish. A liner is cheaper and quicker, although in my view it doesn’t look as good. I’ve compared them in Can I use a liner on my DIY hot tub? If you want to see a tiled finish on a real build, have a look at Patrick’s basement hot tub and cold plunge.

Planning your own build?

Tiling is the fun part, but it only goes well on a shell that’s the right shape, the right size and flat. My DIY hot tub plans give you CAD drawings with every dimension (seats, steps and all), the plumbing layout, a full parts list and the video course. The in-ground build guide takes you from the dig to a watertight shell ready for tiles.

FAQs

Can you use normal tiles in a hot tub?

Not under the water. Use tiles the manufacturer rates for swimming pools, usually glass or porcelain mosaic. Ordinary glazed ceramic wall tiles are more absorbent and aren’t made for permanent immersion in warm, treated water.

Is porcelain or ceramic better for a hot tub?

Porcelain. It’s denser and absorbs no more than 0.5% water by weight, so it resists staining, chemicals and frost far better than ordinary ceramic.

What size tiles are best for a hot tub?

Mosaics. They follow the seats, steps and curves, cope with movement better and give more grip. Larger tiles can work on big flat areas but crack more easily.

Are glass mosaic tiles slippery?

Smooth glass is slippery when wet. Use it on walls, and use the textured anti-slip version, or an anti-slip porcelain mosaic, on steps and floors.

What grout should I use for hot tub tiles?

A swimming pool grade grout, ideally epoxy. It resists the warm, treated and often soft water that washes out cement-based grout.

Got a question about tiling your own tub? Drop it in the comments below. I read them all.

Cheers,
Andi

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Thanks - Andi

 

Hi, Andi here. I own Buildahottub.com and also write all of the articles and info pages on the site. Some years back now, I built my own hot tub but struggled to find the information I needed. So, once my tub was complete, I started this website to help others in their own pursuit of hot tub and plunge pools DIY building information.

Fast forward to 2025, I've helped over 1400+ DIY customers just like you all over the world build hot tubs and pools. Have a good look around the site, there are lots of resources here. Please do get in touch if I can help you. - Cheers, Andi