Does a Sauna Need a Floor Drain?
Not every residential sauna is legally required to have a floor drain, but a drain is strongly useful whenever bathers throw generous water, wash in the room, track in snow, or use the sauna frequently. Whether or not there is a drain, the floor must tolerate water, be easy to clean, dry fully and comply with local building requirements.
Why a drain earns its keep
A real sauna is not a bone-dry cabinet. Water reaches the floor from löyly, perspiration, washing and wet bodies. A drain lets the owner rinse benches and floors without carrying dirty water out by hand. It is especially valuable in outdoor, cottage, rental and commercial settings.
When owners sometimes omit it
Some lightly used indoor saunas sit beside a shower and use modest amounts of water. They may use a waterproof, cleanable floor without a drain, removable duckboards and careful hand cleaning. This is a conscious compromise, not permission to install absorbent flooring.
Floor design checklist
- Confirm whether local code treats the room as a wet area.
- Use a waterproofing system compatible with sauna temperatures and the substrate.
- Slope the floor to the drain where one is provided.
- Turn waterproofing up at walls and detail thresholds and penetrations.
- Keep removable wood duckboards ventilated on all sides.
- Make the area under benches reachable.
- Protect the drain trap from drying or freezing.
Never assume tile and grout are the waterproof layer. The waterproofing is beneath them.
Frequently asked questions
Can a sauna have a concrete floor?
Yes, when properly detailed. Removable wood duckboards make it more comfortable underfoot.
Where should the drain go?
Put it where the floor can slope cleanly and it remains accessible—not directly beneath a heater unless the appliance and plan allow it.