A Home Spa Bathroom: Sauna, Steam Shower and a Retreat Behind Your Own Door

What a home spa bathroom is really about

Wellness is often confused with equipment. A sauna, a steam shower, a rain shower with six programmes. But what works in a good spa is something else: calm, warmth, subdued light and the transition between heat, cooling down and lying still.

That is why we do not begin by asking which appliance you would like. We ask: what does your evening look like when it goes well? Do you use the sauna alone, or together? At weekends, or every other day? Do you go to bed afterwards, or out into the garden? From these answers it becomes clear whether a sauna, a steam shower or an especially good bathtub is the right choice.

A spa bathroom has succeeded when you use it. Not when it looks good in a photograph.

For the couple in Mödling the answer was clear: two or three evenings a week, together, a Finnish sauna, then a cold shower and half an hour of rest. That is a different programme from a quick steam session before work.

The alternative is easy to overlook. Every winter you spend the hours in the car instead of in the warmth, and the storeroom full of suitcases stays what it was. Yet a spa planned as an afterthought can cost more in the end than one planned properly at the start. So what does a sauna in a bathroom demand?

Planning a sauna in the bathroom: space, power and ventilation

A sauna for two can be built on as little as about 1.5 by 1.5 metres if you sit. If you want to lie down, you need a bench length of around 1.90 to 2.00 metres. The cabin height is usually about two metres, so that the heat does not escape too far upwards. On top of that you need floor space in front of the sauna for cooling down and arriving.

Power: the question of the connection

A sauna heater draws a lot of power. Depending on its size, it needs a three-phase connection at 400 volts. Smaller heaters and most infrared cabins manage with an ordinary 230-volt supply. Whether the existing supply can cope, and which cable has to be run to the sauna, is checked by the electrician before planning. In a condominium apartment this may also require coordination with the Hausverwaltung (the building's property management).

Ventilation: the sauna breathes

A sauna needs supply air at floor level near the heater and extract air on the opposite side. The room in which the sauna stands has to deliver this air and then carry the moist heat away again. In a bathroom, which is damp anyway, ventilation becomes the central question. Why this matters so much and how to rule out mould through the building design is explained in our article on ventilation in the bathroom.

A sauna in an Altbau and in an attic apartment

In a Viennese Altbau (the pre-1945 period apartment building), there is an additional question about the floor. A sauna itself is not particularly heavy, but heater, stones, benches and people are concentrated on a small area. On a timber-beam floor we settle this with the structural engineer. Then there is the heat: a sauna gives off warmth to the outside, and adjoining walls should be able to tolerate this without moisture being drawn into them.

At first glance an attic seems ideal, because it often has unused space under the slope. The sauna can even adapt to the slope, with the upper bench placed where the ceiling is highest. What matters is good insulation towards the roof structure and a ventilation route that does not lead the moist air into the roof skin. Many sauna controls can now also be started remotely, so the cabin is warm when you come home. And if there is no room for a sauna at all?

A steam shower in an apartment: what it demands

For apartments, a steam shower is often the more realistic choice. It needs hardly more floor space than a generous shower, from about 1.0 by 1.2 metres, or better larger with a seat. The temperature is around 40 to 50 degrees, the humidity close to 100 per cent. This is precisely what makes it technically demanding.

So that steam does not travel into the rest of the bathroom or into the walls, the cabin must be sealed: glass up to the ceiling, a tight door, and a separate ceiling within the cabin. This ceiling should be slightly sloped or curved so that condensation runs down the walls and does not drip on your head. The waterproofing must run across the full surface of floor, walls and ceiling, not only in the splash zone as with an ordinary shower.

The steam generator sits outside the cabin, for instance in a cupboard, a false wall or an adjoining room. It needs water, power, a drain and above all an access hatch. It has to be descaled and serviced regularly. Where exactly it can stand and how far it may be from the cabin depends on the unit and is planned in detail.

The steam shower forgives no inaccuracy in the waterproofing. What is not sealed there does not show at once, but after two winters.

Which surfaces can take that much heat and moisture?

Materials that withstand heat and moisture

In the sauna itself, timber is the right material, but not every timber. For benches, choose woods that heat up little and are low in resin, such as aspen, abachi or thermally modified woods. For walls and ceiling, Nordic spruce is usual; cedar and hemlock are also used. Varnish and oil have no place in a sauna. Imagine sitting on a bench of pale aspen, the air smelling of warm wood, the glass door slowly clouding over. You can read more about timbers in interiors in Solid wood in interior fit-out.

In a steam shower, by contrast, timber is hardly suitable. Dense, low-porosity surfaces work best here: large-format ceramic, ultra-compact surfaces such as Dekton or dense natural stones with a suitable treatment. Few joints are an advantage, because moisture and deposits collect in joints. We have written about this at length in Large-format ceramic in the bathroom. But a spa is more than heat.

The bathroom as a retreat: light, warmth and calm

Even without a sauna and steam, a bathroom can be a spa bathroom. Often it is a handful of inconspicuous decisions that make the difference.

• Layered light: task lighting at the mirror, dimmed light for the evening, no spotlights directly above the tub. How to achieve this is described in Planning bathroom lighting.
• Warmth from below: underfloor heating makes walking barefoot pleasant and dries the floor faster. What surface heating systems can do is explained in Heating and cooling through surfaces.
• Acoustics and quiet: hard surfaces echo. A textile, a timber element or an acoustically absorbent ceiling calms the room noticeably.
• A place to sit: a bench, a stool, a warm spot after the sauna. Without a rest zone, the most important part of the ritual is missing.
• Order: towels, oils and bathrobes need a place, otherwise they end up everywhere. A made-to-measure cupboard from our joinery Tischlerkultur, which carries on a Viennese carpentry tradition begun in 1935, solves this.

A freestanding bathtub can also be the centrepiece of a spa bathroom. What it requires structurally is covered in Freestanding Bathtub: What Your Room, Floor and Pipework Must Offer.

The sequence of rooms: heat, cooling down, rest

In a thermal spa, the sauna, showers and rest area are arranged one after the other. At home it works similarly, only smaller. Ideally the sauna is positioned so that you step straight into a shower. After that comes a place to lie or sit, perhaps with a view of greenery or a quiet wall.

In the house in Mödling, the storeroom became a sauna with a glass front. The wall to the bathroom was opened so that you step from the sauna directly into the walk-in shower. There, a bucket-style rain shower provides the cold plunge. The bedroom lies opposite, and a wide bench under the window became the rest zone. In this way a sequence of rooms emerged from the bathroom, the storeroom and the hallway. How to plan sleeping, dressing and bathing as one connected area is shown in Sleeping, dressing, bathing.

Planning step by step: from wish to spa bathroom

A spa bathroom involves more trades than an ordinary bathroom. Electrician, plumber, ventilation engineer, joiner, tiler, glazier and sauna builder have to mesh. This sequence has proved its worth:

1. Clarify the ritual: who uses what, how often, at what time of day?
2. Survey the existing conditions: floor area, ceiling height, power, water, waste water, ventilation routes and, in an Altbau, the floor structure.
3. Choose the variant: sauna, steam shower, infrared or a combination.
4. Plan the technology in advance: capacity, cable routes, position of the steam generator, access hatches, ventilation concept.
5. Design: materials, light, sequence of rooms, furniture and storage.
6. Build and coordinate: waterproofing and ventilation are checked during construction, not only at the end.

Because planning and execution come from a single source with us, these steps converge in one person, your contact from the first line to the handover. This matters especially for a spa bathroom, because mistakes usually happen at the interface between two trades, for example between glazier and waterproofing.

What a spa bathroom costs

A spa bathroom is an extension of a bathroom renovation, not a separate product. With a sauna or steam shower, the project is usually clearly more extensive than a standard bathroom.

The cost drivers are less the appliances than the preparation: new power cables, ventilation technology, full-surface waterproofing, glass up to the ceiling and made-to-measure sauna fittings. How the items of a bathroom renovation add up is explained in What does a bathroom renovation cost in Vienna?. The actual costs always depend on the existing building and on the ritual you want, and we talk about them openly from the first conversation.