Short answer: A domestic hammam runs at 45 °C with saturated humidity. Ceiling, joints, bench and generator are all designed around that permanent condensation.
· Wellness · 9 min
The domestic steam room is sold as a shower with vapour. It is not. It is a permanently wet room at 45 °C with saturated humidity, and everything around it — slab, partitions, ceiling, luminaires, door — works with condensation for hours after each session.
When a hammam fails, the generator is rarely the problem. The envelope is.
The whole enclosure is tanked: floor, walls to the ceiling, and the ceiling itself. Liquid polyurethane-cement or a bituminous membrane with reinforcing bands at every junction, corner and service penetration. Any interruption becomes, in time, a stain in the room next door.
The gully must have a bonding flange integrated into the membrane, not simply sit on top of it.
Vapour condenses on the coldest surface, which is always the ceiling. With a flat ceiling that condensation falls in fat drops onto the user's shoulders: complaint number one in badly built steam rooms. The answer is a minimum 2 % fall — ideally a soft vault — so water runs to the walls and down them.
That vault is also what visually separates a good hammam from a tiled box: grazing light across a curved surface is half the experience.
Microcement over epoxy primer, large-format porcelain with minimal joints, low-absorption natural stone or glazed tile. Joints are epoxy grout, never cementitious: standard grout blackens with mould within months.
The bench is built in situ with a 1.5 % fall to the floor and heated, either from underfloor circuits or an embedded element. A cold bench in a 45 °C room condenses and feels unpleasant to sit on.
Rule of thumb: 1 kW per m³, corrected for cold surfaces. The generator lives in a ventilated technical cupboard within 5-6 m of the enclosure, with genuine access for servicing; we have seen units walled in behind plasterboard that had to be cut out at the first service.
The steam outlet sits 25-30 cm above floor level, away from legs and guarded, because steam leaves at 100 °C.
A hammam needs mechanical extraction with a run-on timer: 15-20 minutes after the session ends. Without that drying cycle moisture migrates into the construction, and deterioration starts there. Extraction discharges outside, never into a bathroom ceiling void.
Everything inside the enclosure is extra-low voltage, 12 or 24 V, IP65 as a minimum. Luminaires are recessed and sealed, and fibre optics remain the cleanest solution when you want light with no electrical component inside the room at all.
A properly built bespoke hammam in a private home starts around €12,000-18,000 for 4-6 m³, including tanking, finishes, generator, heated bench, screen and extraction. Prefabricated cabins cost less but rarely fit an existing geometry and never give you the vault.
Programme with construction work: 4-6 weeks, governed by the curing times of the waterproofing.
We draw the hammam in section before plan: ceiling fall, bench levels, steam point and the path of the water. Material comes afterwards. We coordinate the tanking contractor, tiler and installer around a single construction detail, and we test the enclosure for water tightness before anything is clad.
If you want a steam room at home and are unsure whether your current bathroom can take one, send us the dimensions and we will give you a straight answer.
A sauna runs at 80-100 °C with 10 % humidity and is a ventilated timber cabin. A steam room runs at 42-48 °C with humidity close to 100 % and is a sealed tiled or microcement enclosure. They share no envelope, no ventilation and no finish, which is why they cannot be built the same way.
Around 1 kW per m³ of enclosure, corrected upwards for cold surfaces: glass, natural stone or external walls can add 20-40 %. A 5 m³ hammam with a glass screen calls for roughly 6-7 kW.
Because it is flat. Vapour always condenses on the ceiling; without a minimum 2 % fall towards the walls the water drops onto whoever is sitting below. The fix is geometric, not a question of material.
Rinse and dry after each use, weekly cleaning with a non-acidic product, and descaling of the generator every 3-6 months in hard water. Above 25 °fH a dedicated softener significantly extends the life of the equipment.