The majority of our timber comes from a privately owned, sustainably managed woodland in the edge of the Snowdonia National Park.

Each tree has its own characteristics and values. When selecting our timber, the tree is felled, milled and prepared with care, and utilised to its full potential, and there is zero wastage, even the sawdust gets compressed into pellets for solid fuel stoves.

“The forest was initially planted in the period 1940 – 1965 and has been continuously replanted as timber has been removed when it has become mature. The main coniferous species are; Douglas Fir, European Larch, Sitka Spruce, Western Red Cedar, Lawson Cypress, Western Hemlock , Norway Spruce, Noble Fir and Grand Fir. The Deciduous species are; Sessile Oak, Birch, Beech, Chilean Beech and Sweet Chestnut.” – Esgair timber ltd. 

The workmanship

All our saunas are 100% hand made in our workshop in Machynlleth, West Wales, by craftsmen who have a passion for working with timber. Every detail of our work is carefully thought out, and designed to last in the UK weather.

We use no toxic glues or solvents when building our saunas.

The structure

Our outdoor saunas have a built in rigid steel structure, allowing them to be fully built in our workshop to our high standard, then delivered in one piece ready to go.

The entire structure is well ventilated, allowing it to breath both inside the hot room and throughout the structure ensuring no unwanted condensation build up and a long lasting structure. 


With the walls of our saunas being over 150mm thick they are heavily insulated using 100% natural welsh sheep wool. All the heat produced by the stove is contained in a multi layer vapour-proof barrier, this unique combination of insulation and the correct ventilation means our saunas are super energy efficient, optimising heat up times and reducing the amount of fuel needed to reach the desired temperature whilst also maximising health benefits and enjoyment.

The Stove – wood fired & electric heated

We fit all our saunas with Harvia stoves, a Finnish company with over 60 years of experience in the sauna industry. They are available as solid fuel wood fired and also electric heated. The sphere design we use has 120 kg of granite rocks surrounding the stove, retaining the heat for as long as possible meaning the sauna will remain heated for hours event once the fire has died down or gone out.

All flu systems for the solid fuel stoves are well insulated, double walled and made from stainless steel.

Knott free timber – Cedar & Aspen.

We specifically choose Knott free timber for the benches, walls and ceiling. This timber is much more stable over time when exposed to the extreme temperatures and high moisture levels of a sauna.

Why no knots?

Using knotted timber in the hot room of a sauna where temperature exceed 80 degrees, gives the risk of burning your skin as the knots become much hotter than the room itself.  

We typically use Aspen wood for the benches as it has a very low thermal absorption level, meaning it stays relatively cool when the sauna is up to temperature.

We use slow grown Western Red Cedar for the walls and ceiling in our saunas, it is extremely stable in high temperatures and very durable, we’ve found it’s the most suitable material for the job and also smells and looks great!

All Stainless steel fixings

Unlike other saunas available, our saunas are all made using stainless steel fixings ensuring a long life span, and zero corrosion due to the high levels of moisture that a sauna produces.

All seating and walls inside the hot room have hidden fixings, meaning there is no risk of you sitting or leaning back on a hot screw or pin head.



I wanted to make myself an outdoor wood fired sauna, that was of the highest quality, designed to last through the UK’s worst weather, all the time offering my family and friends the luxury, heat and enjoyment of a sauna right outside our own home. I wanted a beautiful, natural design that complemented the surroundings of our house in the mountains, allowing us to relax and enjoy the views from our garden, whilst sweating nicely at 80 degrees, before dousing ourselves with ice cold water.

The sauna industry is often viewed as a ‘leisure centre or spa only’ luxury, but with Heartwood Saunas you can own or hire a beautifully crafted, highest quality, outdoor sauna – delivered for use wherever you choose.

Olly Davey

Director, Heartwood Saunas

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