What Materials Matter Most in Steam Showers?

The most important factor when choosing steam shower wall materials is porosity. Porous materials absorb heat and moisture, which forces your steam generator to work harder and your enclosure to take longer to reach temperature. Non-porous materials hold steam in, heat up efficiently, and keep your system running the way it was sized to run.

Table of Contents

1. Why does porosity matter more than looks?
2. What wall materials work best in a steam shower?
3. What about natural stone — marble, granite, slate?
4. What is Tadelakt, and can you use it in a steam shower?
5. What wall materials should you avoid?
6. How does wall material affect steam generator sizing?
7. Does wall material affect where the Linear SteamHead® should be installed?
8. Frequently Asked Questions

Why does porosity matter more than looks?

Porous materials absorb heat and moisture rather than reflecting them back into the enclosure, which means your steam generator is constantly compensating for the heat the walls are absorbing.

A steam shower works best as a sealed, efficient system. The generator heats water into steam, the steam fills the enclosure, and the enclosure holds that heat until you're done. When the walls are porous—marble, granite, concrete, brick—they act as a heat sink. Steam hits the surface, cools on contact, and condenses before the room reaches temperature. The generator keeps firing to make up the difference.

Non-porous materials like porcelain tile, ceramic tile, and quartz do the opposite. They reflect heat back into the space, the enclosure reaches temperature faster, and the generator runs less to maintain it. Same session, less work, better experience.

This is why wall material is more than an aesthetic decision. Your wall material affects performance, your generator selection, your energy cost, and how long you're waiting before you can actually sit down and relax.

What wall materials work best in a steam shower?

The best steam shower wall materials are non-porous. Non-porous materials don't absorb steam, require oversized generators to compensate, and are built to handle sustained heat and humidity.

Porcelain and ceramic tile remain the most practical choice for most homeowners. Both are non-porous, come in an enormous range of sizes and finishes—including options that convincingly replicate wood, marble, concrete, and brick—and hold up well over years of daily steam use. Large-format tiles (24×24 or larger) reduce the number of grout lines, which simplifies maintenance and reduces the chance of moisture infiltration over time.

Quartz composites (including Caesarstone) are an excellent premium option. The slabs are large enough to install with minimal seams, no grout is required, and the surface is antimicrobial—meaning mold and mildew can't form on the surface itself. Quartz is also highly heat resistant and resists scratching and staining. The maintenance trade-off compared to tile is nearly zero.

Man-made stone in general offers a consistent appearance that natural stone can't guarantee. Without natural variation, you get predictable performance alongside predictable looks, which suits both homeowners and contractors planning an installation.

What about natural stone—marble, granite, slate?

Natural stone is beautiful, and it can work in a steam shower, but it changes the performance equation in ways you need to account for before you buy a generator.

Marble, granite, and slate are porous. They absorb moisture and dissipate heat, which means an enclosure built with natural stone needs a generator sized up accordingly. The standard approach is to add 50% to your basic room volume calculation when sizing for natural stone. So if your enclosure is 100 cubic feet, you size for 150.

Skip that step and the generator you install will be working at capacity every session, struggling to maintain temperature rather than holding it comfortably. Over time, that affects both your experience and the life of the equipment.

If natural stone is the aesthetic you want, go for it, just involve a MrSteam dealer in the sizing conversation early, before anything is purchased. The VirtualSpa® sizing tool accounts for material type, so you can see the generator impact in real time.

One more note: natural stone also requires regular sealing to protect against moisture absorption. Without it, stone in a steam environment will eventually stain, crack, or grow mold in the substrate behind it. The sealing is part of the ongoing cost of the material choice.

What is Tadelakt, and can you use it in a steam shower?

Tadelakt is a waterproof lime plaster that originated in Morocco and has gained traction in modern, minimalist bathroom design. It has no grout, it's naturally resistant to mold, and it creates a smooth, organic surface that's genuinely different from tile.

It can be used in a steam shower with the right preparation. Tadelakt requires proper installation, sealing, and periodic maintenance to maintain its waterproof properties in a steam environment. You'll want to tell your contractor and design team upfront that the room will house a steam shower, so they apply the appropriate sealing protocol from the start.

Sizing-wise, treat Tadelakt the same way you'd treat natural stone: add 50% to the basic room volume calculation. It's more porous than ceramic tile, and the generator needs to account for that.

For homeowners drawn to the texture and warmth of plaster finishes, Tadelakt is a legitimate option. Just don't treat it as maintenance-free.

What wall materials should you avoid?

Some materials that appear frequently in bathroom design have no business being inside a steam enclosure.

Wood is the most common request and the clearest no. It absorbs moisture, swells, warps, and rots. What looks like a stunning design statement will be a mold and structural problem within a year or two of regular steam use. If you want the warmth and grain of wood, use a wood-look porcelain tile instead. The visual result is nearly identical and it will outlast the house.

Concrete has had its moment in design, and it looks excellent in bathrooms, but outside the steam enclosure. Like marble and granite, concrete is porous. It doesn't hold heat or moisture, and it requires constant sealing that will need to be repeated frequently in a steam environment. Concrete tile is an option if the aesthetic matters that much.

Brick is porous and rough-surfaced, which means both moisture absorption and a surface that traps debris and resists cleaning. Brick-look tile handles both problems cleanly.

Venetian plaster and standard plaster finishes—unlike Tadelakt —are not designed to be waterproof. In direct contact with steam and moisture, they will fail. Beautiful on the walls outside the enclosure; not inside it.

Fiberglass is inexpensive and easy to install, but shows wear faster than any other material in high-humidity conditions. If budget is the driver, ceramic tile at the lower end of the price range will outlast fiberglass in a steam application.

How does wall material affect steam generator sizing?

Wall material is one of the core inputs in generator sizing.

The general rule: non-porous materials like ceramic and porcelain tile are the baseline. Porous materials—natural stone, Tadelakt, concrete—add 50% to the effective room volume for sizing purposes. A 100 cubic foot enclosure in tile sizes for a generator rated at 100 cubic feet. The same enclosure in marble sizes for 150.

Generators are engineered to heat a specific volume efficiently. Install an undersized generator in a porous-walled enclosure and it will run continuously, take longer to reach temperature, and wear out faster. Install one that's correctly sized for the material and it runs clean, heats efficiently, and holds temperature without strain.

MrSteam's residential generators are sized by kilowatt output matched to room volume and material type. The VirtualSpa® tool handles the calculation—you enter your dimensions and material, and it recommends the right generator. Run it before any purchasing decision is made, especially if you're considering natural stone or a non-standard finish.

Does wall material affect where the Linear SteamHead® should be installed?

Wall material affects installation planning for the Linear SteamHead® in a few practical ways.

The Linear SteamHead® mounts flush to the wall, 6 to 12 inches above the finished floor. It should never be installed on or directly adjacent to a surface where sustained heat contact could cause expansion, cracking, or moisture infiltration at the mounting point. For tile installations, the steamhead sits cleanly in a standard field tile cut. For stone—particularly thicker slabs—the mounting depth and surrounding material behavior need to be confirmed before installation.

The broader principle: the steamhead location is determined first by function (low on the wall, away from seated bathers, on a wall the steam can rise from freely), and then by the material around it. Don't let a material's installation complexity push the steamhead to a location that compromises performance.

If you're working with large-format quartz slabs or natural stone, involve your contractor in the steamhead placement conversation early. The cut and seal around the fitting needs to be watertight regardless of the surrounding material.

The Bottom Line

The best steam shower wall material is the one that holds heat, resists moisture, and fits the generator you've selected for the space. Non-porous options—porcelain tile, ceramic tile, quartz—are the baseline. Porous materials can be used with the right generator, the right sealing, and realistic expectations about maintenance.

Get the material-to-generator match right from the start and the system runs efficiently for years. Get it wrong and you're compensating for it every session.

Start with the MrSteam VirtualSpa® tool to size correctly for your material choice, and work with a MrSteam dealer to spec the Linear SteamHead® placement before installation begins.

Frequently Asked Questions

What is the best material for steam shower walls?

Non-porous materials are the best choice for steam shower walls because they reflect heat rather than absorbing it. Porcelain tile, ceramic tile, and quartz composites are the most commonly recommended options. They require less generator output to reach and maintain temperature, are resistant to mold and moisture damage, and are available in a wide range of finishes and sizes.

Can you use natural stone in a steam shower?

Yes, but natural stone requires a larger steam generator to compensate for its heat absorption. Add 50% to your basic room volume when sizing a generator for a natural stone enclosure. Natural stone also requires regular sealing to prevent moisture infiltration. It's a viable option with the right planning — just not the most efficient one.

Can you use wood in a steam shower?

No. Wood absorbs moisture and will warp, swell, crack, and eventually develop mold in a steam environment. Wood-look porcelain tile is the recommended substitute — it delivers the same aesthetic without the moisture risk.

How does wall material affect steam generator sizing?

Porous materials — natural stone, Tadelakt, concrete — require a generator sized for 50% more than the actual room volume. Non-porous materials like ceramic and porcelain tile use the actual room volume as the sizing input. Using the wrong calculation for your material leads to an undersized generator that runs continuously and struggles to reach temperature.

What is Tadelakt and can it be used in a steam shower?

Tadelakt is a waterproof lime plaster with roots in Moroccan architecture. It can be used in a steam shower when properly installed and sealed, and it requires no grout. Because it's more porous than ceramic tile, size the generator as you would for natural stone — adding 50% to the basic room volume. Periodic resealing is required to maintain its waterproof properties.

Does wall material affect where the Linear SteamHead® is installed?

Wall material affects the practicality of the installation at the mounting point. The Linear SteamHead® installs 6 to 12 inches above the finished floor, and the surrounding material needs to be properly cut, fitted, and sealed at the fixture. For large-format stone or quartz, confirm mounting depth and seal requirements with your contractor before installation begins.

What wall materials should you avoid in a steam shower?

Avoid wood, standard concrete, brick, Venetian plaster, and standard fiberglass. These materials are either porous, unable to withstand sustained moisture exposure, or both. Many of these aesthetics — wood grain, concrete texture, exposed brick — are available in porcelain tile formats that perform well in a steam environment.

How do I choose the right steam generator for my wall material?

Use MrSteam's VirtualSpa® tool, which accounts for both room dimensions and wall material type in its sizing recommendations. If you're using natural stone or Tadelakt, the tool will adjust the effective volume calculation automatically. A MrSteam dealer can also help confirm the right generator before purchase.