A home steam room is a fully sealed, tiled room fed by a steam generator outside it. What makes it last is hidden: a high-integrity vapour barrier, insulated backing boards, a ceiling and bench shaped to shed condensation, and a way to vent steam outside. Get those right and the tiles can be anything.
Key takeaways
- A steam room runs at very high humidity, so waterproofing and vapour control matter more than the tiles you choose.
- The ceiling and seats should be shaped so condensation does not drip on bathers.
- The steam generator belongs outside the room, with touch controls, and the steam should be exhausted to outside after use.
- Our steam room (Aqua Spazio Vapore) prices start from £19,995, excluding VAT and excluding builders' and preparatory work.
- Most of our steam rooms are built alongside a sauna, often converted from an existing shower room.
How is a home steam room different from a sauna?
A sauna is a timber room with dry heat and low humidity. You add moisture by ladling water on the stones. A steam room is the opposite: lower air temperature and air that is heavy with moisture. Our post on sauna humidity control sets out the typical ranges.
That moisture-laden air is the whole design problem. Every surface is wet during and after a session. Any weak point in the structure behind the tiles will let moisture into the walls, and by the time you see a stain or smell mould, the damage is already done. This is why we treat every steam room as a bespoke build and do not recommend DIY kits.
What goes behind the tiles?
Vapour barrier and tile backing
Our steam rooms use insulated tile backing boards installed over high-integrity vapour barriers. The insulation keeps the tiled surface warm, which reduces condensation and helps the room come up to temperature. The vapour barrier stops moisture from migrating into the timber or masonry behind.
On our loft gym project in Walton-on-Thames, the adjacent shower room was stripped of its old fittings and rebuilt with Marmox insulation board and full waterproofing before any tile went on.
The ceiling and benches
Steam condenses on the coolest surface it meets, and in most rooms that is the ceiling. A flat ceiling drips. We shape the ceiling and the seats so that condensation runs off to the sides rather than falling on bathers. It is a small detail that makes a large difference to comfort.
Drainage
Water has to leave the room. In a shower conversion this usually means a new wet-room tray and drainage. On the Walton-on-Thames project we fitted a new wet-room tray and drainage as part of the conversion. Drainage connections are normally carried out by your main contractor to our drawings.
The steam generator
The generator is mounted outside the steam room, with touch controls, and steam is piped in. We use Harvia (or Insignia) generators. Keeping the unit outside protects it from heat and moisture and makes servicing far easier. Generators are rated by room volume: Harvia lists its HGX60 model, for example, for rooms of 2 to 11 m³. We calculate the right size for each room as part of the design.
Ventilation
Air quality matters in a steam room just as it does in a sauna. Our steam rooms vent the steam to outside through an exhaust after use, so moisture is not left to soak into the rest of the house. In England, ventilation of wet rooms is covered by Approved Document F of the Building Regulations, and any new electrical circuit for the generator and lighting should be designed and installed by a qualified electrician under Approved Document P.
Lighting
Concealed LED lighting is standard in our steam rooms. It gives soft, indirect light without fittings in the wettest areas.
Which finishes work in a steam room?
The finish is where a steam room gets its character. Options we install include:
Finish
What it gives you
Glass mosaic
Reflects light, follows curves on benches and ceilings, classic spa look
Full-body porcelain
Hard-wearing, large formats mean fewer grout lines
Natural stone, slate or marble
Rich, natural look; needs the right sealing and care
A combination we use often is large-format tiles on walls and floor, with mosaic on the seat and ceiling. Mosaic handles the curves of a shaped ceiling and bench, while big tiles keep grout lines (and cleaning) to a minimum elsewhere.
What did we build in North Greenwich?
For Riean Siam Wellness Spa & Sauna in North Greenwich, we built a sauna and a steam room side by side. The steam room is finished entirely in glass mosaic tiles, from the bench to the ceiling, with a single-tier bench. Next to it, the sauna is lined in Thermo Aspen with a robust insulated frame, a slimline vapour barrier, 2+2 floating benches for five to six guests and concealed LED lighting.
The pairing shows why steam rooms and saunas so often go together: warm timber on one side, shimmering mosaic on the other, and two quite different experiences in one wellness area.
How much does a home steam room cost?
Our steam room (Aqua Spazio Vapore) prices, fully installed, are:
Guide price: our steam rooms (Aqua Spazio Vapore) start from £19,995 fully installed, excluding VAT and builders' and preparatory work. The final figure depends on size and finish.
Tiles up to £50 per square metre are included. All prices exclude VAT and exclude builders' and preparatory work. See our prices page for how other ranges compare.
What should you ask your installer?
- What sits behind the tiles? Ask for the vapour barrier and backing board specification in writing.
- How is the ceiling shaped? If the answer is "flat", expect drips.
- Where will the generator go, and how is it serviced? It should be outside the room and accessible.
- How is the steam vented after use? There should be a route to outside.
- Who does the drainage and electrics? Make sure the drawings tell your builder and electrician exactly what is needed.
- Will I get drawings and a manual? We provide layout, mechanical services and joinery drawings, and an operation manual with as-installed drawings.
FAQs
Can I convert an existing shower into a steam room?
Often, yes. We converted a shower room into a steam room on a loft gym project in Walton-on-Thames, stripping out the old fittings and rebuilding with insulation board, full waterproofing and new wet-room drainage. The room has to be fully sealed, so a standard shower enclosure is not enough on its own.
Where does the steam generator go in a home steam room?
Outside the steam room, with touch controls and steam piped in. This protects the unit from heat and moisture and gives easy access for servicing. Generators are sized to the room's volume.
What is the best tile for a home steam room?
There is no single best tile. Glass mosaic, full-body porcelain and natural stone all work if the construction behind them is right. Many of our clients choose large tiles on walls and floor with mosaic on the bench and ceiling.
How much does a home steam room cost in the UK?
Our steam rooms (Aqua Spazio Vapore) start from £19,995 fully installed, including tiles up to £50 per square metre. Prices exclude VAT and exclude builders' and preparatory work such as partitions, drainage connections and electrical supply upgrades.
Is a steam room safe for everyone?
Steam rooms are hot and humid, so keep sessions moderate, drink water afterwards and leave if you feel unwell. Speak to your GP before using one if you have a heart condition, are pregnant, or take medication.
Talk to a sauna designer
Every steam room we build is a one-off, designed around your room, your drainage and your finish. Book a free design consultation, or send photographs and dimensions of your space to info@saunacompany.co.uk for an initial assessment. You can see more on our bespoke steam rooms page.
Planning one for your own home? See our bespoke steam rooms page for options and recent projects, or book a free design consultation and we'll talk through your space.
Sources
- Harvia steam generator HGX60 5.7 kW — manufacturer specification showing generators rated by room volume (2–11 m³)
- Approved Document F: Ventilation (Planning Portal) — Building Regulations guidance on ventilation in England
- Approved Document P: Electrical safety – Dwellings (Planning Portal) — electrical safety guidance for dwellings, referencing BS 7671
Related
- Sauna vs Steam Room: Which Suits Your Home?
- Project: Loft gym sauna and steam room, Walton-on-Thames
- Sauna First or Steam Room First? How to Structure a Session
- Bespoke Saunas in London
- Luxury Home Saunas