Design guide — Garden sauna design
Bespoke garden sauna design guide.
A true bespoke garden sauna begins with design drawings, not a checkout basket. Here's what shapes the design — from site and ritual to materials, performance and cost.
What makes a sauna bespoke
True bespoke design resolves three things together:
The site
Orientation for light, the relationship to neighbours, weather patterns, and the views worth framing.
The ritual
Sauna type, social versus solo layouts, cold-plunge integration, and space to rest.
Architectural expression
Cladding, detailing, window reveals and the proportional refinement that ties it together.
Materials for UK performance
External cladding
- Western red cedar — naturally durable, ages to silver.
- Thermally modified timber — improved stability, a contemporary finish.
- Larch or Douglas fir — cost-effective, but reward careful detailing.
Insulation & structure
- Rigid insulation between studs, with breathable membranes and a vapour-control layer.
- Mineral wool or wood-fibre insulation for heat resistance.
Interior linings
Typically aspen, alder or thermo-aspen — chosen for tolerance to temperature and humidity.
Glazing
Double or triple glazing, toughened glass, minimal framing, and solar-gain management.
Key design elements
Heater specification
Matched to cubic volume, insulation performance and glass surface area. Electric heaters dominate UK residential installations.
Ventilation
Low intake vents near the heater and high exhaust vents, for even heat distribution and moisture control.
Foundations
Concrete slab, ground screws or timber bearers — depending on soil type and permanence.
Planning
Many saunas fall under permitted development when single-storey and within height and boundary limits. See our planning guide.
2026 UK cost ranges
A guide to budget, by level.
- Entry
- £18,000–£25,000 — compact, electric heater, standard glazing
- Mid
- £25,000–£40,000 — larger footprint, premium materials, enhanced insulation
- High-end
- £40,000–£65,000+ — fully custom design, complex glazing, integrated features
Cost is driven by groundworks, electrical upgrades, material specification and design complexity. Figures are indicative — every project is priced to its design.