Installation
What Base Does an Outdoor Sauna Need?
A practical guide to base requirements for Wellness One outdoor saunas — what surfaces are suitable, what to avoid, and how to prepare your site.
By Wellness One Lifestyle · Published 2026-08-02 · Updated 2026-08-02
Base Requirements for Wellness One Outdoor Saunas
A suitable base is essential for a successful sauna installation. The Wellness One installation team will confirm base requirements for your specific model before installation.
What Makes a Suitable Base
A suitable base must be:
- Level — within 10mm level across the full footprint of the sauna
- Load-bearing — capable of supporting the weight of the sauna and its occupants
- Stable — not subject to movement, settling, or frost heave
- Drained — water must not pool under the sauna
Suitable Base Types
Concrete slab — the most common and recommended base. A 100mm reinforced concrete slab is ideal. The slab must be level and cured before installation.
Paving slabs — suitable provided they are laid on a compacted sub-base and are level. Individual slabs must not rock or move.
Composite decking — suitable provided the subframe is structurally sound and the surface is level. Composite is preferred over timber decking as it is dimensionally stable.
Existing patio — suitable if level and load-bearing.
What to Avoid
- Timber decking that is soft, rotten, or uneven
- Grass or soil (without a suitable sub-base)
- Gravel (without a solid sub-base)
- Any surface that is not level or load-bearing
Site Access
The installation team requires vehicle access to within a reasonable distance of the installation site. The sauna is delivered in sections — each section is manageable by the installation team, but clear access is required.
Frequently Asked Questions
What base does an outdoor sauna need?
The sauna requires a level, load-bearing base within 10mm level across the full footprint. Suitable bases include concrete slabs, paving slabs, and composite decking. The Wellness One team will advise on base requirements for your specific model.
Can I put a sauna on decking?
Yes, provided the decking is structurally sound, load-bearing, and level. Composite decking is the preferred option as it is dimensionally stable and resistant to moisture.