Steam & Oak Kesä 480 XL Sauna Garden Room — Lounge, Sauna and Terrace

The Kesä 480 XL is the largest building in the range: 6.81 m across in total, with sliding patio doors onto a lounge, a separate sauna room, and a covered terrace big enough to furnish properly.

Built in 70 mm solid log, 4.61 m deep.

A garden room first, with a sauna built in

The extra width over the Kesä 460 goes into the lounge — 2.6 m rather than 2.0 m — and into a 2 m covered terrace. That is the difference between a room you change in and a room you would actually sit in with people.

Sliding patio doors open the lounge to the terrace, so in summer the two become one space. The sauna room keeps its own door off the lounge.

Why 70 mm logs

Solid 70 mm log throughout. On the sauna side that is thermal mass — walls that store heat and hold temperature steadily. On the lounge side it is a building with enough substance to use in spring and autumn, not just high summer.

Available in black or natural spruce.

Specification

What's in the box

Everything structural. No hidden extras to buy before you can build it:

• Pre-cut, numbered 70 mm log walls
• Sauna benches
• Sliding patio doors, glazed doors and windows
• Internal partition wall
• Covered terrace structure and posts
• Roof covering
• Floor and foundation beams
• Complete fixing kit
• Ventilation grids
• Step-by-step assembly instructions

Run the sauna on gas — no electrician, no cable across the garden

A FinSteam gas heater runs on a standard propane bottle — the same sort you would use for a patio heater or a barbecue. No armoured cable, no trench across the lawn, no electrician's quote you had not budgeted for.

The sauna room is around 8.2 m³, so the 8.1 kW heater is well matched to it.

One honest caveat on a building this size: gas heats the sauna room, not the rest of the building. If you want the lounge heated in winter too, you will need a power supply for that regardless — so the gas option makes most sense if the lounge is a three-season space, or if you are heating it another way.

Pick a gas option above and we fit the flue and commission the heater on installation day.

Which gas option?

And then: safety pack, or without?

Every gas option includes the heater, the Orbis stone cage, and our fitting and commissioning. See the full gas heater range →

Or choose electric or wood-fired above

Electric — a Harvia heater with a full stone load, integrated controls and a 2-year warranty. On a building like this you are likely running a supply out anyway for lighting and sockets, so the marginal cost of a sauna circuit is lower than on a standalone cabin. Budget £400–£1,200 for the garden supply itself.

Wood-fired — a Harvia M-series stove. No electrics needed for the sauna at all. We fit the flue on installation day. If you are in a smoke control area, check the model against DEFRA's exempt appliance register first — see our smoke control area guide.

2-year warranty

Two years on the structure and on the heater, whichever heat source you choose. Covers manufacturing defects and workmanship.

Planning permission — read this before you order

This matters more on a garden room than on a small sauna, and we would rather you knew now.

Most garden buildings fall under permitted development, but the rules have real limits. The ones that catch people out:

• Total footprint. Outbuildings must not cover more than half the land around the original house.
• Height near a boundary. Within 2 m of a boundary, the whole building is limited to 2.5 m — which a building like this will exceed. Site it further in, or you are into a planning application.
• Listed buildings and conservation areas. Different rules apply, and they are stricter.
• Sleeping accommodation is not permitted development. A lounge is fine; a guest bedroom is not.

Our planning permission guide goes through it properly. If in doubt, a call to your council's planning department costs nothing and settles it.

The base

A building of this size and weight needs a concrete slab — level, load-bearing and well drained. Paving on gravel is not sufficient here. Budget £800–£2,000 for the base depending on ground conditions and access, and have it laid and cured before delivery day.

Ground should fall gently away from the slab. Timber sitting in standing water fails regardless of how well it was built.

Lead time — please ask before you order

Lead times vary with stock and specification — anything from 2 to 12 weeks. Ask us before you commit and we will give you the real date for the exact build you want.

Getting it into your garden

At roughly 2800 kg across multiple pallets, this needs proper access — a driveway or hard standing for unloading, and room to move long logs to the build position. Send us photographs of the route before you order and we will tell you honestly whether it will work.

Our construction service starts at £500, and on a building this size we would strongly recommend it — we apply insulating paste between every panel as we build, which is the single biggest factor in whether the sauna holds its heat. Full installation guide.

Options

Choose your heater above. Finish comes in black or natural spruce — tell us your preference when you order. Ask us anything before you commit.

Images are manufacturer renders. The heater shown is illustrative — your heater choice is made above. Furniture and hot tub not included.