How to clean a steam room: tile, grout, mosaic, terrazzo, stone and glass

The short answer

• After each session: rinse the walls, benches and floor with clean water, squeegee glass and smooth surfaces, check the floor waste, and let the room dry the way it was designed to, whether that is a drying cycle, a fan or the door left open.
• Regularly: wash with a cleaner that suits every finish it touches, including the grout and any sealer, then rinse well and dry.
• Know your finishes. Ceramic tile, porcelain, epoxy grout, cement grout, glass mosaic, terrazzo and marble all tolerate different chemicals. There is no single cleaner for all of them.
• pH-neutral is the safe default. Acidic limescale removers suit only acid-resistant surfaces, and cement grout, terrazzo, marble and limestone are not among them.
• Treat the steam outlet, sensor and controls gently. Clean the outlet only when cold, never block it, and wipe the sensor and fittings rather than spraying them.
• No abrasives, no product mixing, no high-pressure water at seals, penetrations and fittings.

Your installer’s and finish manufacturers’ instructions govern. This guide explains the principles behind them.

Room cleaning versus generator maintenance

A steam room has two quite different maintenance jobs:

• The room (tile, grout, glass, benches, door, outlet, drains and fittings) is cleaned by the owner or operator. That is what this guide covers.
• The steam generator (water, scale, the automatic drain, descaling and servicing) follows its own manual and service schedule. See our guide to steam generator maintenance and steam generators and water quality.

The two meet at the steam outlet and the floor drain, so both are covered here only as far as the owner’s side goes. Owners never open electrical equipment or dismantle the generator.

After each session

Most steam-room cleaning happens in a couple of minutes after each use, while the residue is still fresh and soft.

1. Switch off at the control, as the manual describes, so any automatic drain or drying cycle can run. Don’t stand at the outlet while the generator is still hot.
2. Rinse the benches, walls and floor with clean water, working from the top down, to carry skin oils, soap and product residue to the floor waste.
3. Squeegee the glass and other smooth surfaces. The Australian Glass and Window Association says squeegeeing glass, hardware and frame after every use is the simplest way to prevent water spots and mineral deposits, and the Natural Stone Institute recommends a squeegee after each use in wet areas to minimise soap scum. Use a squeegee without a metal holder that could scratch the glass.
4. Check the floor waste for hair and debris and make sure water is draining away.
5. Dry the room as designed. Harvia’s steam generator manual asks owners to make sure the steam room dries properly after use. Depending on the system, that may mean a drying function on the control, a fan that runs after the session, or the door left open. Harvia’s steam controls include a drying function. If the design relies on the door being left open, leave it open; if the room has a fan or drying cycle, let it finish.
6. Take everything out: towels, bottles, scrubbers and anything else that can hold water against a surface.

Why this matters: water left to evaporate leaves its minerals behind as spots and film, and residue that dries on is harder to shift and tempts people towards stronger chemicals. A room that dries fully after each session also stays cleaner between deeper cleans.

Regular cleaning

How often a steam room needs a thorough wash depends on how much it is used, the water hardness, the finishes and whether it is a home or commercial room. No manufacturer we reviewed sets a single interval for the room itself, so none is given here.

A good general routine for a deeper clean:

1. Let the room and generator cool, and keep the generator off while you work.
2. Pre-wet the surfaces with clean water. Several cleaner makers ask for this so the product works on the surface, not in the grout.
3. Apply a cleaner suited to all the finishes it will touch, mixed as its label says. Let it sit for the stated time but don’t let it dry on. The National Terrazzo & Mosaic Association gives the same advice for terrazzo.
4. Agitate with a soft brush, sponge or non-scratch pad, with a soft-bristled brush for grout lines, textured mosaic and corners.
5. Rinse thoroughly with clean water, top to bottom, so no cleaner residue is left on surfaces or in grout.
6. Squeegee and dry the room as you would after a session.

Test first. Grout, tile and cleaner makers all ask for a test in an inconspicuous area before using a new product. Harvia also recommends a separate cleaning light in home steam rooms (it is mandatory in public ones) so surfaces can be inspected properly during cleaning.

While cleaning, look at the silicone joints, grout and door seals. Cracked sealant or grout lets moisture behind the tiles, where damage is hidden. Our caring for your sauna (and steam room) guide covers these checks as part of the owner’s routine.

Know your finishes before choosing a cleaner

Cleaning compatibility depends on the actual tile, stone, grout and sealer in your room, not on how it looks. Two mosaics that look alike may be glass on epoxy grout or marble on cement grout, and need quite different care. The people who know are your installer and the product manufacturers, so keep their care instructions with the room’s handover documents.

A room can combine several finishes. One room we have worked on has uneven mosaic walls and a terrazzo floor, for example, so the walls and floor need to be considered separately: a textured mosaic that traps residue and a floor that needs a pH-neutral approach.

Ceramic and porcelain tile

Glazed ceramic and porcelain are dense and resist most cleaners, which is why they are so common in steam rooms. Routine cleaning with a pH-neutral tile cleaner is enough for most rooms.

For limescale or mineral film, an acidic cleaner can help, but only where it is safe for everything it touches. Harvia’s heater cleanser is an acidic product described for acid-resistant materials such as glass, tile and porcelain: dampen the tiles first, leave it for 10–15 minutes, scrub, then rinse carefully, and don’t use it with chlorinated products. Mapei likewise warns that its acidic tile and grout cleaner etches polished marble, limestone and concrete and may lighten cement-based materials. The tile may cope; the grout and any stone nearby may not.

Why this matters: in a steam room the grout lines and silicone joints are the weak points, not the tile face.

Grout: cement-based or epoxy

Most steam-room problems with cleaning come back to the grout.

Cement-based grout is porous. Mapei’s maintenance guide notes that it readily absorbs water, dirt, oils and other contaminants. Grout makers recommend routine cleaning with a pH-neutral cleaner. Ardex Australia states that its cement-based grouts cannot take acidic cleaning solutions and corrode in contact with acid, so the cleaning agent must be neutral or alkaline. Laticrete says no cement grout needs sealing to perform, but sealing improves stain resistance and ease of maintenance; Mapei describes protection and routine cleaning as musts.

Epoxy grout is far more chemical-resistant. Laticrete says its epoxy grouts never need sealing, and Ardex says its epoxy grouts can handle an acidic cleaning solution within their published chemical-resistance tables. Harvia recommends epoxy grout for home steam rooms and requires it in public ones, because ordinary grout wears under heavy use.

Bleach. Ardex allows bleach on its grouts only when well diluted, because strong bleach can affect the oxides that colour the grout. Never mix bleach with ammonia or acids; the Natural Stone Institute warns that bleach and ammonia together produce a toxic gas.

Sealing in a steam room. A grout sealer must suit constant vapour and the room’s temperature. Ask the installer which grout was used and whether, and with what, it should be sealed and resealed. Ardex also recommends regular inspection so damaged grout can be repaired promptly, because contamination enters through gouges and cracks.

If you don’t know which grout you have, assume it is cement-based and use pH-neutral products until the installer confirms otherwise.

Mosaic

“Mosaic” describes the size of the pieces, not the material. Steam-room mosaics can be ceramic, porcelain, glass, natural stone or a blend, laid on cement or epoxy grout. Their care therefore follows the most sensitive material in the sheet and the grout between it: a glass mosaic on epoxy grout tolerates far more than a marble mosaic on cement grout.

Mosaic also has many more grout lines per square metre than large tiles, and handmade, uneven or textured mosaic has edges and hollows where residue collects. That calls for:

• a rinse after every session to carry residue away before it dries;
• a soft-bristled brush rather than a cloth for regular cleaning, so cleaner reaches the texture and grout without scratching the face;
• careful rinsing, because cleaner left in the texture dries to a film.

Tile makers advise against scouring pads, steel wool and abrasive powders on glass and decorative mosaic. If the composition isn’t known, ask the installer or supplier before using anything stronger than a neutral cleaner.

Terrazzo

Terrazzo is made of marble or other aggregate set in a binder, which may be Portland cement, polyacrylate-modified cement or epoxy resin. The National Terrazzo & Mosaic Association (NTMA) gives clear care principles:

• Use neutral pH cleaners, made for terrazzo, mixed to the maker’s instructions.
• Let the cleaner sit for several minutes to loosen dirt, but don’t let it dry on the surface; rinse with plenty of clean water.
• Don’t use degreasers, bleach, vinegar, ammonia or other household chemicals, or all-purpose cleaners containing crystallising salts, harmful alkalis or acids.
• Seal with a suitable sealer applied to the sealer maker’s instructions, and strip and reseal as required. Avoid surface waxes and all-purpose sealers, which can make floors slippery.

NTMA also notes that even standing water can eventually damage some sealers. Its guidance is written for terrazzo floors generally, not steam rooms specifically, so in a steam room confirm with the installer and sealer maker that the sealer suits continuous moisture and heat, and that the floor stays slip-resistant. NTMA advises contacting a terrazzo contractor before deviating from its instructions.

Natural stone: marble, limestone and travertine

Marble, limestone, travertine and onyx are calcareous: made mainly of calcium carbonate, which acids dissolve. The Natural Stone Institute warns that lemon, vinegar and other acids can dull or etch these stones, and recommends a neutral cleaner, stone soap or mild liquid dishwashing detergent in warm water. In wet areas it recommends a squeegee after each use and a non-acidic soap-scum remover. Abrasive creams and powders can scratch stone. Sealers make stone more stain-resistant, not stain-proof.

Siliceous stones such as granite, slate and quartzite are generally more tolerant of mild acids, Mapei notes, but the sealer and grout still decide what is safe.

Harvia advises avoiding porous natural stone in steam rooms because it tends to erode. Where stone has been used, there is no universal recipe: follow the stone supplier’s, sealer maker’s and installer’s instructions. Limescale removers and generator descalers must never reach stone surfaces; one generator maker warns that descaler reaching the steam line can damage marble and limestone in the room.

Glass doors and screens

The Australian Glass and Window Association’s shower-screen guidance applies well to steam-room glass:

• Squeegee glass, hardware and frame after every use.
• Use warm, mild, pH-neutral soapy water; never let a cleaning solution stay on any surface.
• Never use abrasive cleansers on glass, hardware or frame; watch rings and jewellery.
• Rinse thoroughly, then dry with a lint-free cloth or clean squeegee, working from the top down.
• Check fixings and hardware periodically for looseness.

AGWA also notes that continuous wetting and drying can raise the alkalinity of the glass surface and cause a cloudy appearance, which is another reason to squeegee and dry. Glass with a factory hydrophobic coating should be cleaned only as its maker instructs.

Benches

Steam-room benches are usually tiled or stone, and they carry most of the body contact and residue. Clean them like the wall finish they’re made of, with extra attention to the front edge and the junction with the wall, where residue and water collect. Benches are designed to fall slightly so water drains; if water ponds, tell the installer rather than scrubbing harder. Sitting on a towel reduces the residue left behind.

Door, seals and hinges

• Wipe door seals and gaskets with a mild, pH-neutral solution and rinse. Avoid solvents and abrasives, which can damage seals.
• Keep hinges and handles clean and dry, and report stiffness, sagging or a door that no longer closes as designed.
• Don’t pack towels against the door gap. Some systems, including Harvia’s, rely on a gap under the door for supply air.
• Check silicone joints at the frame for cracks or lifting while you clean.

Steam outlet

The steam outlet (nozzle or steam head) is part of the generator system, but it sits in the room and gets cleaned with it.

• Clean it only when the generator is off and the outlet is cold. Harvia warns that the nozzles become scalding hot in use and that the steam itself is scalding.
• Harvia’s commercial generator manual says the nozzles can be cleaned with a mild soap solution. Don’t use abrasives or take the outlet apart.
• Never block or cover it. Harvia asks users to make sure steam vents freely from the nozzle before starting; if nozzles or pipes are blocked, the generator releases steam through its overpressure valve.
• Keep descalers and acidic cleaners off the outlet unless the generator manual says otherwise. Scale inside the generator is a generator maintenance job, covered in our steam generator maintenance guide.

Floor waste and drains

Hair, soap and skin residue collect in the floor waste and its grate. Lift the grate and clear the trap regularly, rinse it, and make sure the floor drains freely after each session. A slow drain leaves water standing on the floor, which marks finishes and works on grout and sealers.

Avoid caustic drain cleaners near stone or terrazzo, and never mix drain products with other cleaners. Persistent slow drainage, smells or water appearing outside the room are matters for a licensed plumber.

Controls, sensor and lights

• The temperature sensor sits in the ceiling or high on the wall. Wipe it gently with a damp cloth; never spray it or hose it, and never pull it from its sealed hole.
• Light fittings in the room are sealed into the vapour layer. Wipe them; don’t spray cleaner or water at the fittings or their sealant.
• The control panel is outside the room on Harvia systems. Wipe it with a barely damp cloth and never spray liquid onto it.
• Owners never open electrical equipment or bypass safety devices. If a light, sensor or control is cracked, loose or behaving strangely, stop using the room and call a licensed electrician or authorised service person.

Body oils, products and residue

Skin oils, soap, shampoo, oils and other body products travel with condensation down the walls and settle on benches, lower walls and the floor. Over time they build a dull film that grips minerals from the water and makes surfaces slippery.

The simplest controls are upstream: shower before using the room, sit on a towel, and keep body products and oils out of the steam room unless the room and generator makers allow them. Use only fragrances made for steam generators, through the system designed for them. Then rinse after each session and clean regularly with a suitable cleaner.

Commercial steam rooms

A commercial room is used for many hours a day by many people, so cleaning becomes a written routine with logs, staff training and products approved for each finish. Disinfectant choice, dilution, contact time and staff safety are matters for the operator’s work health and safety advice and the local council’s environmental health officer, and products must suit both the finishes and the chemical manufacturer’s instructions. Our guide to commercial saunas and steam rooms covers hygiene, supervision and an operator checklist.

What not to use

When to call for help

• Cracked or missing grout or silicone, a door that no longer seals or closes as designed, or water appearing outside the room: call the installer.
• Etching, staining or dulling on stone or terrazzo: stop cleaning with that product and ask a stone or terrazzo specialist.
• Leaks, repeated tripping, fault codes, spitting at the outlet or weak steam: call a licensed or authorised service person. Our troubleshooting guide explains common symptoms.

BSC Wellness works with a dedicated electrical contractor, an independent business and a Harvia-authorised service agent, who carries out our electrical servicing. See our service page or request a service.