Ethelia Wellness — September 2026 — 9 min read
Short answer: a float tank room is a small room with four hard requirements — a floor that carries well over a tonne on a small footprint, salt-proof materials and drainage, acoustic and light isolation, and air handling that holds a warm, humid room without condensation. In Indonesia, the specialist works for the room typically cost $12,000–$25,000 on top of the tank itself, and they cannot be left to a general contractor.
This guide is for spa and wellness operators planning float or sensory deprivation rooms — including the growing number of enquiries for sensory deprivation tanks in Jakarta, where most projects are fit-outs inside existing towers and shophouses.
A float pod is a closed tank with a lid. It is compact, holds its own heat and is easier to fit into an existing building. An open float room (a float cabin) is a walk-in room where the solution fills the floor area and the whole room becomes the tank. It feels less enclosed, which helps first-time and claustrophobic guests, but it turns the room itself into a wet, salt-exposed structure — walls, ceiling, door and lighting all have to be built for it. Pods suit tight fit-outs; open rooms suit new builds where the structure can be designed around them.
A float tank holds a shallow bath with 500–600 kg of Epsom salt dissolved in it. Filled, it weighs well over a tonne on a footprint of a few square metres. On a ground-floor slab that is usually fine; on an upper floor of an office tower or a timber-framed villa it must be checked by a structural engineer before the room is drawn. In Jakarta high-rise fit-outs this check, together with building-management approval for wet works, often sets the location of the float room before anything else.
Saturated magnesium sulphate solution corrodes ordinary steel and attacks many fixings, and it travels: on feet, towels and in the air near an open tank. Everything inside the float room and its shower should be salt-tolerant — plastic or suitable stainless-steel fixings, sealed floor finishes, no exposed mild steel. Drainage lines from the room and the shower should be plastic, laid with real falls, and the route for emptying or replacing solution should be planned with the tank supplier. Every float room needs a shower next to it: guests shower before and after each session.
The product is silence and darkness, so the room is built as a room within a room. Partitions run to the structural slab rather than to a suspended ceiling, the door is solid-core with perimeter seals, and no plumbing, pump or chiller shares a wall with the tank. The filtration pump — which runs between sessions — sits on isolation mounts, ideally in an adjacent plant cupboard. Lighting is low-voltage, dimmable to full darkness, and switchable by the guest from inside.
The solution is held at about skin temperature, roughly 34–35.5°C, and the room air should be close to it so the guest feels no boundary between water and air. In Indonesia’s climate the problem is not heating but humidity: a warm, wet room next to air-conditioned corridors will sweat on every cold surface. The float room needs its own extraction, a vapour barrier on the warm side of its walls and ceiling, and a door that keeps humid air out of the corridor. Shared ductwork with dry rooms is the most common and most expensive mistake.
| Element | Requirement | Why it matters |
|---|---|---|
| Floor | Structural check for over 1 tonne; sealed, salt-tolerant finish | Load and corrosion |
| Walls and ceiling | Full height to slab, vapour barrier, acoustic insulation | Silence and no condensation |
| Door | Solid-core, perimeter seals, salt-tolerant hardware | Sound, light and humidity |
| Plumbing | Plastic drainage with falls, adjacent shower, solution disposal route | Salt and hygiene |
| Plant | Filtration pump on isolation mounts, service access outside the room | Noise and maintenance |
| Electrical | Residual-current protection, low-voltage lighting inside the room | Safety in a wet room |
| Air | Dedicated extraction, room air close to solution temperature | Comfort and building fabric |
In our published wellness center cost breakdown, the acoustic and waterproofing works for a float room run $12,000–$25,000, depending on pod or open room and on how much isolation the building needs. The tank itself is priced separately by brand; imported equipment adds 10–18% of its value in import and customs costs. One float tank is part of our Core level ($150K–$250K); centers with three or more tanks and premium isolation sit higher — see pricing.
For operators in Java, our wellness center construction in Jakarta page covers logistics and permitting there. The float room is one of the specialist rooms we build under wellness center construction, and tanks are installed and commissioned under equipment installation.
Planning a float or sensory deprivation room? Send us the floor plan and the floor level on WhatsApp — we will tell you whether the space works, what the room needs and a first cost range.
Check Your Float Room PlanThe specialist acoustic and waterproofing works typically cost $12,000–$25,000, plus the tank itself and 10–18% import costs on imported equipment.
Often yes, but a filled tank weighs well over a tonne on a small footprint, so a structural engineer must confirm the slab first. In Jakarta towers, building management also has to approve wet works.
Pods are compact and easier to fit into existing buildings; open float rooms feel less enclosed but turn the whole room into a salt-exposed wet structure. The building usually decides.
The solution is kept at about skin temperature, roughly 34–35.5°C, with room air close to it; in a tropical climate the main task is controlling humidity.