How to Prepare Your Bathroom or Spare Room for Sauna Installation

Step 2: Check the floor and structure

A sauna is heavy, hot and occasionally wet. The floor beneath it must be up to the job.

The ideal sauna floor is:

• Level: an uneven floor puts stress on panels and the door
• Solid: able to support the sauna, heater, stones and bathers
• Water-resistant: ceramic tile, porcelain, concrete or vinyl work well
• Heat-tolerant: avoid materials that warp or melt under warm conditions

Floors to avoid or replace

• Carpet: traps moisture and can become a mold and fire risk
• Solid hardwood or laminate: may warp from heat and moisture
• Uneven or damaged tiles: fix and level them first

In a spare room, you can often lay tiles or a waterproof vinyl floor in the sauna area only. In a bathroom, existing tiles usually work perfectly.How to Prepare a Bathroom or Spare Room for a Home Sauna

Upper floors and older homes

If the sauna is going upstairs or into an older building, ask your installer or a structural engineer to confirm the floor can carry the load.

Step 3: Prepare the electrical supply

Electrical preparation is the most important step, and it must always be done by a licensed electrician.

What your electrician should check

• Heater power rating: traditional heaters often draw several kilowatts; infrared saunas usually draw less
• Supply capacity: whether your home’s main supply can handle the extra load
• Dedicated circuit: most saunas need their own circuit and breaker, with the correct cable size
• Single or three-phase: some larger heaters need three-phase power
• Earth-leakage (RCD) protection as required by local rules and the manufacturer
• Connection point: an isolator or junction box in the position shown in the sauna’s installation manual

Bathroom electrical safety

Bathrooms have strict rules about electrical equipment near baths and showers. The sauna’s control panel, heater and connection point must be positioned safely outside wet zones or rated for them.

Always follow local regulations and the manufacturer’s instructions.

Tip: Share the sauna’s spec sheet with your electrician before you order. That way, the circuit is ready when the sauna arrives.

Step 4: Plan ventilation and air conditioning

A sauna needs fresh air during use and a way to dry out afterward.

Traditional sauna ventilation

• Fresh air intake low on the wall near or under the heater
• Exhaust outlet higher up on the opposite wall or under the bench
• A small gap under the sauna door
• Room ventilation so warm, moist air leaving the sauna can escape the room

Room ventilation checklist

• A working exhaust fan or window in the room
• Space around the sauna for air to circulate, as per the manual
• Exhaust air not blown into the AC return or ceiling void
• AC vents not blowing directly on the sauna cabin

In hot climates like the UAE, where rooms are air-conditioned most of the year, plan the sauna’s position so cold AC air and hot sauna air don’t meet inside walls. This prevents condensation and mold.

Step 5: Prepare the walls and ceiling

How much wall preparation you need depends on whether you’re installing a freestanding cabin or a built-in sauna.

Freestanding (modular) saunas

These have their own insulated walls and roof. The room’s walls simply need to be clear, dry and at the right distance from the cabin.

Built-in (custom) saunas

Here, the room’s walls become part of the sauna. They typically need:

• Framing (timber battens) to create a gap for insulation
• Heat-rated insulation such as mineral wool
• A foil vapor barrier with taped seams, facing the hot side
• An air gap before the wood paneling
• Wood paneling fixed to the battens

If there are tiles on the existing walls, the installer can usually build the framing in front of them. Ask before removing anything.

Lowering the ceiling

A lower ceiling heats faster and costs less to run. Built-in saunas often have a dropped ceiling at about 2.0–2.2 m, even if the room is taller.

Step 6: Protect the room from moisture

A sauna produces heat and some humidity, especially when water is thrown on the stones. That moisture needs a safe place to go.

In a spare room

• Protect nearby walls and furniture from warm, moist air
• Make sure the vapor barrier is continuous on built-in saunas
• Use moisture-resistant paint on surrounding walls if needed
• Remove or relocate wooden furniture, books and electronics close to the sauna

In a bathroom

• Keep the sauna away from direct shower spray
• Check existing grout and silicone for cracks
• Make sure the bathroom exhaust fan is working and sized for the room
• Plan for the extra humidity from both the shower and the sauna

Step 7: Plan access, delivery and a clear workspace

Sauna panels, benches and heaters are large and heavy. Plan the route from the front door to the room in advance.

Delivery checklist

• Measure doorways, corridors, stair turns and lift sizes along the route
• Compare them with the largest panel dimensions from the supplier
• Arrange parking or building access for the delivery vehicle
• Book the service lift and notify building management if you live in an apartment or managed community

Preparing the room on installation day

• Remove furniture, rugs, curtains and décor from the room
• Take down wall art and shelves near the sauna area
• Protect floors along the route with sheets or boards
• Make sure there’s light, a power socket for tools and space to unpack
• Keep children and pets away from the work area

Step 8: Plan the shower and cool-down area

The sauna experience doesn’t end when you step out. A good cool-down area completes it.

• Shower nearby: a quick cool rinse is part of traditional sauna culture
• Towel hooks or a heated towel rail close to the sauna door
• A place to sit and relax, such as a bench or lounge chair
• Water station to rehydrate
• Non-slip flooring where people step out wet

In a spare room without a bathroom, plan the shortest, safest route to the nearest shower.