A tiled hammam or steam room at 43-48 °C, built to dry out between sessions

Hammam, steam room, steam bath: one system, three names

A hotel calls it a hammam, a gym calls it a steam room, a tender sometimes calls it a sauna. On this page it is one system: a tiled or mosaic cabin held at 43-48 °C by a steam generator, at humidity close to saturation, with a bench, a glass door, a drain in the floor and an extract that dries the room after use. It is the opposite room to our dry cabins at 90-110 °C; the terminology note shows how to write the difference into a BOQ. Where the brief wants both, the two stand side by side with a cold plunge pool in front of them.

Hammam or dry sauna: the honest comparison

Generator size by cabin volume

Indicative figures for a tiled cabin with a glass door; stone-clad walls, a glass wall or a tall ceiling push the generator up one size, and the generator's datasheet decides. The layout states the volume and the ambient the size was chosen for.

The shell is the product

• Waterproofing and a vapour barrier behind every tile, carried over the ceiling and down to the drain, flood-tested before tiling. A hammam that breathes steam into the structure next door grows mould in one monsoon.
• A sloped ceiling of roughly one in ten, so that condensate runs to the walls and not onto a bather's neck; a vault does the same job with more grace.
• Benches at seat height in tile or honed stone, heated under the finish where the operator wants a warm seat for the first guest of the day.
• A floor drain with a fall from every corner, a glass door with a threshold, wet-room lighting, and an extract that runs after the session until the room is dry.

Monsoon humidity and the drying cycle

A hammam has to dry between sessions. In Goa, where June and July bring close to 1,799 mm of rain between them (IMD, 1981-2010), and in Mumbai, where 96% of the year's rain falls from June to September (IMD, Santacruz, 1991-2020), the air the extract pulls in is already wet, so the drying cycle runs longer and the fan is sized for the monsoon, not for March. A room that never dries smells, stains its grout and loses its ceiling tiles first. The drying time goes into the controls and the operator's log, and the extract discharges outside the building, not into a service corridor.

Water: the generator drinks what the borewell gives

A steam generator boils water and leaves its minerals behind. Borewell water in Delhi NCR, Hyderabad and much of Bengaluru can be hard; fed untreated, the generator scales within weeks and its element fails early. A TDS and hardness test before the order decides between a softener on the feed, a mains fill and a descaling schedule; the generator's automatic flush and its drain are drawn with the cabin.

Power and the generator set

A 9 kW or 12 kW steam generator is a three-phase load with its own feeder and DB way, and not a candidate for the inverter. Where the site runs on a generator set during cuts, the set is sized for the steam generator and the extract together, or the hammam waits for the mains; the controls restart the cycle after a cut without a visit from the caretaker. The BOQ states the supply the utility confirms, since an older feed may still read 240/415 V.

Clubs, hotels and the farmhouse

A club puts the steam room where members pass after the cold pool, and peak-hour duty sets the generator and the extract. A hotel wants it as an architectural room: mosaic, a vault, a bench for eight, a brass bowl, with the generator behind the wall. A farmhouse takes a cabin for two to four beside the farmhouse sauna, for the cool season when the family wants warmth without a 90 °C cabin.

Five lines for the BOQ

1. Cabin: plan, ceiling height and slope, volume in m³, people, bench layout and the heated-bench option; climate 43-48 °C with the ambient assumed.
2. Steam generator: rated kW, supply, feeder and DB way, and the certification the bidder claims for it.
3. Water: feed, hardness and TDS result, softener if needed, drain at the generator, automatic flush.
4. Shell and services: waterproofing with the flood test recorded, tile schedule, floor drain and falls, door, wet-room lighting, extract fan and drying cycle with its discharge route.
5. Commissioning: temperature and humidity log, drying-time check and a signed test before the last 20%.