& Ruutu 230 Thermowood Cube Sauna Glass Front Gas — Aurora 81 safety pack

Steam & Oak Ruutu 230 Thermowood Cube Sauna Ruutu is Finnish for a square pane, the kind you look through. The Ruutu range is built around that idea: a squared cabin with softly rounded corners and a front that is almost entirely glass. The Ruutu 230 is 2.3 metres by 2.3 metres, in 46mm thermowood, held together with stainless steel bands, with a hot room of about 8.5m³ and a two metre bench run along the side wall. Why the corners are rounded On a conventional cube the roof and the walls meet at hard edges, and every edge is a joint where rain can sit and work its way in. On the Ruutu the roof curves down into the sides, so one continuous skin of bitumen shingles runs from the base on one side, over the top, to the base on the other. There is no roof to wall joint for water to find, and nothing flat for it to pond on. Inside, the same curve leaves fewer tight corners where air stalls. The glass front The front is 8mm tempered, tinted glass: two full height panes, one of them the door, and a narrow pane either side. That is roughly 3.1m² of glass looking out from the bench. Tinted glass cuts glare and gives some privacy from outside while the view from inside stays clear. Glass also loses heat far faster than solid timber, which is why the heater choice below matters more on this cabin than on a closed cube. Why the bands are stainless The Ruutu is built like a barrel: solid staves held in compression by steel bands, rather than thin cladding over a frame. Timber shrinks each time the sauna is heated and dries out, then swells again through a wet British winter, so the bands work constantly and need checking and re-tightening over the life of the sauna. Ordinary steel bands eventually rust, and rust runs down the timber and stains it. Stainless steel does not. What thermowood actually does Thermowood is timber that has been heat treated at around 200°C rather than chemically preserved. The process breaks down the sugars and resins that fungus feeds on and permanently reduces how much moisture the wood can reabsorb. The practical result outdoors is timber that moves less through wet British winters, resists rot without chemical treatment, and holds its shape in a structure that depends on staying tight. A note on wall thickness: 46mm solid staves give the cabin plenty of thermal mass, but how warm a sauna stays is governed far more by the glass, the ventilation and the heater than by a few millimetres of timber. Choose the Ruutu for the design, the glass and the build rather than for a thickness figure. Also available with gas — no electrician, no chimney, no fire to tend Pick a gas option at checkout and your cabin ships gas-ready: engineered ventilation built for gas, plus a bundled FinSteam gas heater package — ready to light on a UK propane bottle the day it lands. Steam & Oak is the only UK retailer offering this on a thermowood cube. Hot in 15 minutes, turn a dial. The Aurora 81 is the only CE-marked electricity-free sauna gas heater on the European market (FinSteam's stated claim), and the heater that powers the FinSteam NOIR Signature packages. Why gas changes the equation Gas Wood Electric Heat-up time ~15 min, dial 30-45 min, tend a fire 30-60 min Electrician / wiring None None 50A circuit (£800-£1,500) Chimney / flue None Required None Smoke, ash, soot None Every session None Off-grid / power-cut Yes Yes No Humidity Naturally humid (combustion vapour) Dry until löyly Dry until löyly Running cost / session ~£2.00-2.50 £2-4 logs £2.00-3.25 Safety EU-cert, auto O₂ shut-off Open flame Electrical The real cost to your first löyly An electric sauna's shelf price is not the price to your first session. The 9kW Harvia needs its own dedicated circuit on 10mm² cable, wired by a qualified electrician and signed off under Part P — typically £800–£1,500, more again over a buried run to the end of a garden, plus the wait to get one booked. The gas heater connects to a propane bottle outside: no dedicated circuit, no trench across the lawn, and it is hot on the day it arrives. Against the wood fired M3, gas gives you the same freedom from the grid without the flue, the chimney route we would otherwise have to agree, or anyone building and tending a fire before every session. What gas-ready means The gas variants ship with wooden louvre vents at the FinSteam-specified sizes built into the cabin: intake ≥350 cm² low next to the heater drawing fresh air directly from outside, exhaust ≥250 cm² high in the opposite corner discharged directly to outside. FinSteam explicitly exclude plastic disc and twist valves. The vent configuration and the heater are certified together under EU Gas Appliance Regulation 2016/426. Pick a wood fired or electric variant and the cabin ships with the appropriate vent set for that heat type. Which gas option? Botnia 81 Our standard 8.1 kW gas heater. Everything you need to run the sauna. Aurora 81 The premium version of the same 8.1 kW heater — better finish and detailing, which suits