Steam & Oak Kesä 688 Spa Garden Room — Sauna and Covered Hot Tub Shelter

The Kesä 688 puts a sauna and a covered hot tub shelter under the same 6.88 m roof — so the tub stays out of the rain, the sauna is two steps away, and neither needs its own separate structure in the garden.

Sauna and hot tub, one building

The building is 2.59 m wide and 6.88 m long, divided into three: a 3.0 m covered bay sized for a hot tub, a 2.0 m sauna room, and a 1.3 m room for changing and storage.

The reason this works better than two separate buildings is the bit in between. Sauna, cold water, somewhere dry to sit — all within a few steps and all under cover. In a British winter, that is what determines whether a hot tub and sauna get used together or used separately and rarely.

The hot tub bay is a covered shelter, open at the front. It suits most standard tubs, but send us your tub's dimensions before ordering and we will confirm the fit rather than guess.

Built in 45 mm timber

45 mm walls — more substantial than the 42 mm panel cabins, and appropriate for a building where only one of the three sections is heated.

Specification

What's in the box

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

• Pre-cut, numbered wall sections
• Sauna benches
• Doors and glazing
• Internal partition walls
• Covered hot tub bay structure
• 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. Note the hot tub needs its own supply regardless — a tub is an electrical appliance and gas does not change that.

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 2400 kg and nearly 7 m long, this needs a driveway or hard standing for unloading and a clear route to the build position. The hot tub itself is delivered separately — plan the order of works so the tub goes in before or as the shelter is completed, not after.

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. Tell us your hot tub's dimensions when you enquire and we will confirm the bay suits it. 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.