What Is the Best Wood for a Sauna? A Guide for Melbourne Buyers
Alana Farina | ๐ info@thesaunacompany.com
TLDR; Quick Answer
The best wood for a sauna is Western Red Cedar.
It's a light, low-density softwood with natural decay resistance, low resin content and excellent dimensional stability, so it stays comfortable to touch at 80 to 100°C.
Use tight knot cedar on walls and ceilings and clear grade cedar where you sit. For a neutral scent indoors, choose Canadian Hemlock. For outdoor cladding, choose Thermo Spruce or cedar. For a Japanese-style sauna, choose Hinoki.
Avoid pine and treated timber.
A range of timbers are available from our Heidelberg West warehouse, with pick-up or Victoria-wide delivery.
Best Wood for a Sauna at a Glance
Sauna wood selection starts with where the timber sits in the room.
Our pick
Also from our range
Avoid
The Breakdown: What You'll Find
The right choice depends on where the timber sits, whether you're building an indoor sauna or an outdoor barrel or cabin sauna, your budget and your aroma preference.
Jump to:
How Do You Choose Wood for Each Part of a Sauna?
Why Are Softwoods Best for Saunas?
What Is Thermally Modified Wood?
Can You Use Australian Hardwoods in a Sauna?
๏ปฟHow Do You Choose Wood for Each Part of a Sauna?
Choose sauna wood for the job it does: walls and ceilings need stability and low resin, benches need low density and no knots, and outdoor cladding needs to be weather-resistant.
Walls and ceilings
Walls and ceilings make up most of the timber in your sauna. They take the full heat of the room and the burst of steam every time you throw water on the stones, so they need:
- Dimensional stability, so boards don't shrink, cup or open up gaps through constant moisture cycling.
- Moisture resistance, to cope with humidity rising and falling in every session.
- Low resin content, so there's no sap leakage when the room heats up.
- The right look and aroma for how you want your sauna to feel.
Our pick: tight-knot Western Red Cedar. Canadian Hemlock if you want a pale, neutral-scent room, or Hinoki for a Japanese-inspired finish.
๏ปฟBenches, backrests and headrests
Benches, backrests and headrests are the timber your skin touches directly, so bench comfort comes first.
The best bench slats are:
- Low-density wood. Light, soft timber has low thermal conductivity, which means it doesn't hold or pass heat to your skin the way dense timber does.
- Knot-free. Knots are denser than the surrounding wood, so they create hot spots and can weep resin.
- Smooth, with no splinters. Fine-grain wood construction gives benches a silky surface that stays comfortable session after session.
Our pick: clear grade Western Red Cedar bench timber. Bench frames can be a sturdier timber, as long as they sit out of reach.
Outdoor sauna cladding
An outdoor sauna has to handle what the Melbourne weather throws at it: heavy rain, strong UV exposure, temperature swings and, closer to the bay or the coast, coastal humidity and salt air.
Outdoor sauna cladding needs:
- Good outdoor rot resistance
- Proper weather protection
- A plan for termite management
Our pick: Thermo Spruce or Western Red Cedar.
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Why Are Softwoods Best for Saunas?
Softwoods are best for saunas because their low density gives them low thermal conductivity, so they stay comfortable to touch in high heat. Every timber in our range is a softwood for this reason.
Softwoods like Western Red Cedar, spruce and hemlock are light, open-celled timbers with low thermal conductivity. They warm up gently and don't hold heat at the surface, so you can lean back against the wall at 90°C without flinching. Most hardwoods are far denser, so they feel hotter to touch and are more likely to develop hot spots on benches.
Low-density wood also tends to be more dimensionally stable through heat and moisture cycling. That matters in a room that goes from room temperature to near boiling, then back again, several times a week.
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Our Sauna Timbers, One by One
Western Red Cedar
Western Red Cedar, also sold as Canadian Red Cedar, is the timber we build with most and the one we'd recommend for most saunas. It's the lightest, softest timber in the table, and its heartwood is naturally durable against decay
Its natural oils give cedar its distinctive aroma. Most people love it. If you'd prefer a neutral scent, choose hemlock walls instead.
The trade-off:
- Cost. Cedar sits at the premium end. Because it lasts, many owners find it the better value over the life of the sauna.
Canadian Hemlock
Canadian Hemlock is pale, even-textured and almost scent-free, with a clean, modern look. It's usually more affordable than cedar and performs well in indoor saunas, where conditions are controlled.
The trade-off:
- Not suited to outdoor cladding. It's denser than cedar and isn't naturally decay-resistant.
For the full head-to-head, read our cedar vs hemlock sauna comparison.
Thermo Spruce
Thermo Spruce is Nordic Spruce that has been thermally modified. Nordic Spruce is the traditional Finnish sauna timber: light, with only a very slight scent, but not naturally decay resistant. Thermal modification changes that, which is why Thermo Spruce is our pick for outdoor sauna cladding.
The trade-off:
- Not fit for all purposes. Use this only for outdoor cladding, sauna walls and ceilings It isn't suitable for load bearing. It also conducts heat and is not suitable for where the body will touch.
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Hinoki (Japanese Cypress)
Hinoki is a Japanese cypress that has been used in Japanese baths, temples and wellness spaces for centuries. It's light and pale, with a fine, straight grain and a soft, fresh, slightly lemony scent that many people find calming.
It's naturally durable and copes well with heat and humidity.
Hinoki suits anyone after a Japanese-inspired sauna or a lighter, brighter finish than cedar. It's a premium timber, sourced direct from Japan.
The trade-off:
- Cost & Expertise. It's considered a luxury timber and must be applied correctly to maximise its lifespan.
What Is Thermally Modified Wood?
Thermally modified wood is timber that has been heated to high temperatures in a low-oxygen kiln. The process is chemical-free: it uses only heat and steam.
Thermal modification breaks down the hemicellulose and wood sugars in the timber, which are the parts that absorb water and feed decay fungi.
The result is wood with:
- Better dimensional stability and moisture resistance
- Improved natural decay resistance
- Darker, even colour all the way through
- Light smoky scent when it's new
Can You Use Pine for a Sauna?
We don't recommend pine for a sauna. Local radiata pine is resinous, dense and not durable enough for constant heat and moisture, and treated pine should never be used inside a sauna.
Pine is one of the most-searched sauna timbers in Australia because it's affordable and easy to find. But the pine sold locally is usually radiata pine, a plantation timber grown for construction, and it isn't a good match for a hot room:
- Sap leakage. Radiata pine is resinous. At 80°C or more, resin can soften and weep from boards and knots.
- Hot spots. It's around 40% denser than Western Red Cedar (515 vs 370 kg/m³), and its knots feel hotter still against your skin.
- Durability. Radiata pine heartwood is rated non-durable to perishable, so it won't stand up to constant moisture cycling.
Never use treated pine inside a sauna. Treated pine (the H-rated timber sold for decks, fences and garden beds) is impregnated with chemical treatments designed for outdoor and in-ground use. Those preservatives have no place in a small room you heat and breathe in.
You may see pine in European saunas. Slow-grown Nordic pine and thermally modified pine are different products from local radiata pine. If you're considering one of those, give us a call and we'll talk it through.
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Can You Use Australian Hardwoods in a Sauna?
Most Australian hardwoods aren't a good choice for the hot room because they're dense, heavy and run hot to the touch. Australia grows some of the world's best hardwoods, so it's natural to ask whether eucalyptus or another local timber could work. In most cases, we'd steer you away from hardwoods for the hot room:
- Most eucalypts are dense. That means higher thermal conductivity, hotter benches and more hot spots.
- Weight. Dense hardwoods are heavy and harder to work into fine tongue and groove lining.
- Movement. They can move more through heat and moisture cycling.
One name that confuses buyers is Australian red cedar (Toona ciliata). Despite the name, it's an unrelated native rainforest timber, prized for furniture and in limited supply. It isn't the same as Western Red Cedar and isn't a standard sauna timber.
What Should You Check Before Buying Sauna Timber?
Before buying sauna timber, check its grade, heartwood content, moisture content at delivery, profile and fixings. Species is only half the decision. These specifications make the difference between a sauna that looks great for decades and one that gaps, stains or weeps in its first year.
Grade: clear vs knotty
Western Red Cedar is sold in grades, and you'll see names like:
- Clear Heart: heartwood with virtually no knots.
- A Clear: a premium clear grade.
- Select Knotty: sound, tight knots with a more rustic look.
Clear grade timber is the premium choice for benches, backrests and headrests. Knotty grades suit walls and ceilings and are more affordable. Avoid loose or open knots anywhere in a sauna, as they can drop out once the timber heats.๏ปฟ
Heartwood vs sapwood
Heartwood is the denser, more stable inner part of the tree. In cedar, it carries most of the natural decay resistance. Sapwood is paler and less durable. Sauna-grade cedar should be predominantly heartwood.
Moisture content at delivery
Sauna timber should be kiln dried and at the right moisture content at delivery. Timber that's still carrying moisture will shrink once the heater runs, opening gaps between boards. If your timber has been stored outdoors or in a damp space, let it acclimatise indoors before installing.
Profile and tongue and groove (T&G) installation
Most sauna lining is tongue and groove, so boards lock together and fixings stay hidden. Our standard Western Red Cedar lining profile is 84 x 10 mm, in lengths from 1.8 to 2.7 m. Good tongue and groove installation leaves a small expansion allowance, so boards can move without buckling.
Commercial rooms and multi-residential buildings
Saunas in commercial rooms, gyms or multi-residential buildings may need to meet National Construction Code fire hazard requirements for internal linings. Check with a sauna expert.
What Should You Keep Out of a Sauna?
A sauna should be built from natural, non-toxic materials that are stable in the heat. Inside the hot room, avoid:
- Varnish, lacquer, paint or ordinary stain. These can soften, discolour or give off fumes in the heat.
- Plywood and VOC glues. Engineered boards rely on adhesives that aren't designed for high-heat interiors.
- Treated timber of any kind.
- Experimental materials. If a product isn't proven in sauna conditions, keep it out of the hot room.
A note for DIY builders
Cutting and sanding cedar creates fine dust. Western Red Cedar contains plicatic acid, which can irritate some people's airways. Use dust extraction where you can, wear respiratory protection such as a P2 mask, and work in a ventilated space.
So, Which Sauna Wood Should You Choose?
Walls and ceilings
Western Red Cedar, or Canadian Hemlock for a neutral scent and lower cost indoors.
Benches, backrests and headrests
Clear grade cedar, aspen or basswood, with no knots.
Outdoor saunas
Western Red Cedar or thermally modified timber such as Thermo Spruce.
Avoid
Radiata pine, treated pine, dense hardwoods, varnish and plywood inside the hot room.
Still deciding? That's normal. Most of our customers have a few questions about sauna timber before they commit, and we're always happy to help.
Ready to Start Your Sauna?
Whichever way you want to build, we'll help you choose the right timber.๏ปฟ
Building your own?
Order Western Red Cedar lining, SAWO heaters and every material you need from our Heidelberg West warehouse, with Victoria-wide delivery.
Want a kit?
Our prefabricated cedar sauna kits arrive cut and ready to assemble.
Prefer it done for you?
Our team designs and builds custom saunas across Melbourne.
Not sure which timber suits your build?
Call us on 0429 303 271 or send us your plans, and we'll talk you through the options. You're welcome to visit our showroom at 23 Percy St, Heidelberg West, to see and feel the timbers in person.
Frequently Asked Questions
Victoria's Trusted Sauna & Steam Room Specialists
The Sauna Company provides end-to-end SAWO sauna/steam room services Victoria-wide:
- Comprehensive consultations pre-purchase
- Delivery statewide
- All of our sauna rooms are constructed from premium grade materials including circa 70mm thick double insulated wall panels which are lined on both sides with 14mm kiln dried western red cedar boards
- Certified carpenters build our custom saunas
- We utilise colour bond skillion roofs to our outdoor saunas
- Certified electricians handle install wiring
- All waste + rubbish is cleaned on-site at your convenience
- Ongoing post-purchase maintenance and customer service support
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