Custom vs Prefabricated Sauna: Design, Delivery, Service

Sauna Dekor Spa Solutions engineering team, Istanbul · project and press enquiries: Alican Aykaç, Managing Partner

Last updated: 11 November 2026

Both routes can give a good sauna. The difference is where the decisions are made. A prefabricated sauna fixes most of them at the factory, before anyone has seen the room. A custom sauna makes them on the drawings of the room itself. Which one is right depends on the space, the programme and how the sauna will be used.

Table of contents

• What is the difference between a custom and a prefabricated sauna?
• What is a prefabricated sauna?
• What is a custom sauna?
• How does the design process differ?
• What happens to the room around the sauna?
• How do glass fronts change the choice?
• How do delivery and installation differ?
• What about service and spare parts?
• Which suits a Gulf villa or hotel?
• What does a made-to-measure cabin look like?
• Frequently asked questions
• Sources

A prefabricated sauna is a ready-made cabin in a catalogue size; a custom sauna is drawn for one room. The 2 differ in 6 places: who sets the dimensions, how the cabin meets the walls, how glass is handled, how it reaches site, how long installation takes and how it is serviced later.

Neither column is better in every case. A prefabricated cabin is predictable and quick to order. A custom sauna takes more drawing time and gives more control over how the room looks and works. The rest of this page goes through each row.

A prefabricated sauna is a factory-made cabin, sold in set sizes and finishes, that arrives as wall, ceiling and bench elements and is assembled inside an existing room. Harvia, for example, lists 3 routes: a ready-made indoor sauna cabin, a custom-designed bathroom sauna and an outdoor sauna.

The cabin carries its own insulated walls, ceiling, door, benches and lighting, and the heater and control are chosen from the maker’s range for that cabin size. Tylö describes the same split from the buyer’s side: a pre-built sauna room, or building your own.

The strength of a prefabricated sauna is that the decisions have already been made and tested on many identical cabins. Its limit is the same: the cabin’s sizes, bench layouts, glass sizes and finishes are the maker’s, and the room has to accept them. Infrared cabins are almost always supplied this way, which is why our page on the types of sauna heaters treats them separately from built rooms.

A custom sauna is designed for one room and made to its measurements: walls, ceiling, benches, glass, lighting and heater position are drawn for that space and those users. It can be a free-standing cabin or a sauna built into the walls of the room. We make ours in 6 primary timbers, from ayous to thermo-pine.

The timber list for our custom saunas is ayous, thermo-ayous, aspen, thermo-aspen, low-resin pine and thermo-pine; hemlock, red cedar, alder and, rarely, spruce are used on request. Our guide to sauna wood explains how each timber behaves in heat.

Custom does not have to mean complicated. Many of our custom saunas are simple rectangular rooms; what makes them custom is that the bench runs the full length of the wall that is actually there, the door sits where the corridor needs it, and the glass is the size of the opening the architect drew. Our page on choosing the right sauna room covers the size and layout questions that come first.

With a prefabricated sauna, the design is choosing a model. With a custom sauna, it is a sequence of 4 fixed decisions before the interior: heater, ventilation, door and glass. Tylö’s building guide puts them in that order, and its advice is to plan benches and backrests last, once those are fixed.

The order matters because each decision limits the next. The heater position decides where the air comes in. The door works with the heater, so Tylö recommends placing them on the same wall or on adjacent walls close to each other. Glass sections change how much heat the room needs. Only then can the benches be drawn so that guests sit in the right place relative to the heat.

The electrical design is part of the same early stage. Harvia’s design guidance is that the electrical work in a sauna is planned well in advance, because the supply cables run inside the wall insulation; once the surfaces are installed, it is too late to change the wiring. Our page on sauna electrical requirements covers the supply side.

A sauna is always a room within a room. A prefabricated cabin brings its own insulated walls and stands clear of the building’s walls; a custom sauna either does the same or builds its insulation and panelling against the existing walls. Tylö asks for an air gap of about 20 mm against an outer wall and at least 45 mm of insulation.

That build-up is where the two routes differ most on site. A free-standing cabin, prefabricated or custom, needs space around it and a ceiling void above it, and it does not touch the structure. A built-in custom sauna uses the room’s own walls, so the vapour barrier, insulation and panelling are installed against them and the sauna occupies every centimetre of the space.

Tylö’s guidance also lists the materials that do not belong inside: plasterboard, chipboard, OSB and glued wood composites, which can release odours or lose their strength in the heat. A prefabricated cabin solves that by being timber throughout. In a custom sauna, the same rule is applied to every surface the drawings show, including the ceiling.

Glass is where most custom saunas start. A prefabricated cabin offers standard glass fronts in set sizes; a custom sauna sizes the glass to the architecture. Tylö’s guide adds 1 m³ to the sauna’s volume for every square metre of glass, tile or stone when the heater is chosen.

That rule is why glass is decided before the heater, not after. A full-height glass front looks like a small change on a drawing and is a large change in how the room heats and recovers between sessions. In a custom sauna, the heater, the glass area and the bench positions are chosen together; in a prefabricated cabin, the maker has already matched them for each model.

Glass also brings the sauna into the rest of the space. In villa wellness rooms and bathrooms, a sauna with a glass front reads as part of the room rather than as a box in a corner; our page on the bathroom sauna shows how that works when the sauna shares a room with a shower.

A prefabricated sauna is shipped as a kit and assembled in the room; a custom sauna is made in our workshop, then assembled and finished on site. For a single custom sauna, installation takes about 2 weeks; large projects with many rooms can run up to 6 months.

The time on site is not the whole programme. A custom sauna needs measured drawings, approval of the drawings and manufacturing before it ships, while a prefabricated cabin can often be ordered from stock. On the other hand, a custom sauna is drawn around the real site, including how the panels reach the room: through which door, in which lift and up which stairs.

In the Gulf, the electrical supply and the room’s finishes are usually the critical path for both routes. The cabin cannot be connected until the supply is ready, and it cannot be finished until the surrounding floor and walls are. For outdoor saunas, where foundations and weather add their own steps, our outdoor sauna guide covers the prefabricated and custom routes for gardens and terraces.

Service depends less on the route than on the parts. The heater, control and lighting in either sauna are made by their manufacturers and serviced with their spare parts. The difference is in the timber: a prefabricated cabin is repaired with the maker’s panels, a custom sauna with parts made to its 1 set of drawings.

For a hotel, the question is what happens in year five, when a bench board is damaged or a panel is stained. With a prefabricated cabin, the answer depends on whether that model and finish are still made. With a custom sauna, the drawings and timber specification stay on file, and a replacement part is made to them.

The heater is the other service item. In a prefabricated cabin it is chosen from the cabin maker’s range; in a custom sauna it is chosen for the room from a heater manufacturer’s range. In both cases, the heater’s installation manual sets the clearances, the supply and the maintenance, and those instructions belong to its manufacturer.

A prefabricated sauna suits a regular room, a standard layout and a short programme. A custom sauna suits a room with glass, odd dimensions, a sauna that is part of the architecture, or a hotel that needs to repair it for years. We see 3 recurring cases where custom is the safer route.

• Glass and views. Villas in Dubai, Riyadh and Doha often want a sauna with a full glass front onto a wellness room, garden or pool. That is a custom glass elevation, with the heater chosen for it.
• Room shapes. Basements, under-stair spaces, sloping roofs and niches rarely match catalogue sizes. A custom sauna uses the full space instead of leaving gaps around a box.
• Hotel use. A hotel sauna runs for long hours and has to be maintained for years. Bench length, ventilation and access for cleaning are drawn for that use, and spare timber parts are made to the same drawings.

Where none of those applies, a prefabricated cabin can be a sound choice. A guest bathroom with a regular corner and no glass requirement is the typical example.

A custom sauna is still a cabin; it is simply drawn for one room. At the Grand Millennium Hotel in Sulaymaniyah, completed in 2013, we made the sauna to the measured room: slatted benches in 2 tiers on three walls, lantern lamps and the thermometer at eye level.

More of that project is on our page on the Grand Millennium Hotel sauna. The benches turn the corners without a gap and meet the walls on every side, which is the kind of detail a catalogue cabin in a standard size does not give a room with its own dimensions.

In a custom sauna the cabin, glazing, benches, lighting and heater come from one contractor, which is the other difference from a kit: the cabin and the room’s finishes are coordinated on one set of drawings. In hotels the same applies at a larger scale; at Hilton Istanbul Maslak, delivered in 2017, the spa and pool were built together.

Sauna Dekor has designed, manufactured and installed saunas, steam rooms, hammams, pools and cold plunges since 1987: 40 years of manufacturing in Istanbul, in our own facility in İkitelli OSB, with a team of 19 employees and 5,000+ projects in 41+ countries. We work under TS EN ISO 9001:2015, certificate no. 202025106. Our offices are in Istanbul (İkitelli OSB), Dubai (Latifa Tower, World Trade Centre) and Boston (66 Long Wharf, Unit 4B). We also have representative offices in Bodrum, Monheim am Rhein (Germany), Haarlem and Doha.

We design and manufacture the sauna room itself: walls, ceilings, benches, glass fronts, lighting and finishes, made to the drawings of each project. We do not manufacture sauna heaters or controls; their manufacturers make them, and their technical documentation and conformity marking belong to those manufacturers. The TS EN ISO 9001:2015 certificate is ours. On the work we deliver, the terms are a 24-month warranty on workmanship and manufacturing; 24-month manufacturer’s warranty on electrical and mechanical equipment; 5-year warranty on structure and waterproofing.