At Backcountry Recreation, we offer a range of barrel saunas designed to provide a relaxing and rejuvenating experience. The choice of wood is one of the most consequential decisions in sauna construction — it affects durability, comfort, maintenance requirements, and how the sauna performs year after year in Canada's demanding climate. Below is a detailed look at the six most commonly considered wood types for outdoor saunas, along with an honest assessment of where each one excels and where it falls short.
Clear Red Cedar (A or B & Better Grade)
Clear Canadian Western Red Cedar — also known as A & Better Cedar — is a grade of Western Red Cedar that is mostly free of knots. For a fully knot-free option, Clear Vertical Grain Cedar is available, though it can be difficult to source and carries a significant price premium. Backcountry Recreation uses only the highest quality clear grade cedar in its saunas, ensuring consistent quality across every unit.
Western Red Cedar is one of the most commercially valuable wood species in North America. Its natural resistance to termites, rot, and decay makes it outstanding for outdoor applications, and its attractive dark colour, lightweight feel, and soft texture have made it a benchmark material for roof shingles, exterior siding, cladding, decking, and saunas for generations.
Pros
- Lightweight and easy to work with — planes, shapes, and sands to a smooth satin finish
- Natural resistance to rot, decay, and termites without requiring chemical treatment
- Contains natural antimicrobial compounds that inhibit mould and bacterial growth
- Glues easily and holds fasteners reliably
- Stays cool to the touch on bench surfaces even at high temperatures
- Provides the distinctive intense cedar aroma that defines the traditional sauna experience
- Beautiful, consistent dark grain with unparalleled visual appeal
- Can last for many decades when properly maintained
- Suitable for all sauna surfaces including benches, walls, and ceilings
Cons
- More expensive than most alternative sauna woods
- A small percentage of users may have cedar allergies or sensitivity to the aroma
- May require periodic light maintenance to preserve natural beauty and protect against weathering
- Can be susceptible to surface discolouration if left unprotected from standing water or prolonged moisture contact
Scandinavian Thermowood
Scandinavian Thermowood is a Scandinavian softwood that undergoes a specialized heat-treatment process in chamber kilns for up to 96 hours at temperatures between 180°C and 230°C (356°F–446°F). Steam is used as a protective gas throughout the process to prevent splitting or structural damage. This treatment produces both chemical and structural changes that fundamentally alter the wood's performance characteristics.
The most significant benefit of Thermowood is dimensional stability. The intense heat removes virtually all moisture and resin from the timber, resulting in a wood that responds far less to changes in humidity than untreated alternatives. The result is a material that resists warping, cracking, and shrinkage far more reliably — and one that will never ooze sap or resin at sauna temperatures.
Pros
- Dimensionally stable due to extremely low residual moisture content — minimal warping or twisting over time
- Resistant to decay and insects as a result of the heat treatment process
- Reduced splitting and cracking risk due to tension release during treatment
- Increased durability and lifespan compared to untreated wood of the same species
- Reduced need for ongoing maintenance and preservation treatments
- Improved thermal insulation properties relative to untreated softwood
- Non-toxic and environmentally responsible production process — no chemical preservatives used
Cons
- More expensive than untreated wood due to the specialized production process
- Limited availability in some Canadian regions
- Requires specialized tools and care to work with, as the treatment increases hardness and brittleness
- The heat treatment produces a uniform warm brown tone — limited colour variation available
- Not appropriate for all woodworking applications due to the altered structural characteristics post-treatment
Select Tight Knot Cedar (Heritage or Rustic Cedar)
Select tight knot cedar is a lower grade of cedar that contains knots — areas where branches have grown through the timber. While knots can give the wood a rustic, natural aesthetic that some buyers find appealing, they carry important performance drawbacks in sauna applications that are worth understanding before purchasing.
Because a sauna expands and contracts with every heat cycle, the knots — which are considerably denser than the surrounding wood — tend to loosen over time and can eventually fall out entirely, leaving unplanned gaps in the wall or ceiling. Those same dense knots also retain heat at a much higher rate than the surrounding timber, creating hot spots on bench surfaces that can cause skin burns and make seating uncomfortable.
Select tight knot cedar typically costs around 60–70% less than clear cedar, and any finished sauna built with it should reflect that price difference accordingly. If budget is a genuine constraint, knotty cedar can be acceptable for exterior wall cladding where direct skin contact is minimal — but clear cedar should always be used for benches and backrests. What you save in upfront price, you give back in longevity, beauty, and long-lasting enjoyment.
Pros
- Significantly lower cost than clear cedar — typically 60–70% less
- The natural knot pattern gives a rustic, heritage aesthetic that some buyers prefer
- Still retains cedar's baseline natural resistance to rot and insects in the clear wood zones
- A practical option for wall cladding where skin contact is not a factor
Cons
- Knots can loosen and fall out over time as the sauna expands and contracts, creating ventilation gaps
- Dense knots retain heat disproportionately and can cause skin burns on bench surfaces
- Not suitable for bench or backrest surfaces — a safety risk in direct-contact applications
- Shorter lifespan and higher long-term maintenance requirements than clear cedar
Western Hemlock
Western Hemlock is sometimes considered as a cost-saving alternative to cedar, but it falls short in several key areas for sauna construction. Hemlock's straight grain — while visually consistent — makes it prone to splintering, which is a significant drawback for any surface that will be in direct contact with skin. Cedar's superior pliability and strength make it a better choice for all aspects of sauna construction, and hemlock is generally better suited to structural framing applications within buildings rather than interior sauna finishing.
Pros
- More affordable than cedar
- Natural resistance to decay and rot makes it reasonably durable for outdoor use
- Straight and uniform grain provides a consistent visual appearance
- Lightweight and easy to handle during construction
- Has a pleasant mild aroma at elevated temperatures
Cons
- Prone to splintering — a serious comfort and safety concern for bench and backrest surfaces
- Less pliable and structurally resilient than cedar, which affects long-term sauna durability
- Lower natural resistance to insects and pests compared to cedar
- Requires more maintenance than cedar to preserve appearance and performance over time
- Does not carry the same aesthetic warmth or aromatic quality as cedar
Pine, Fir, and SPF
The SPF group — Engelmann Spruce, Lodgepole Pine, and Subalpine Fir — is among the most widely available and affordable softwood options in North America. It offers a high strength-to-weight ratio and is easy to work with, making it common in flat-pack furniture, interior finishing, concrete formwork, and structural framing. However, SPF's low natural resistance to moisture and decay makes it a poor choice for outdoor sauna applications when left untreated, and it requires consistent maintenance to prevent warping, cracking, and rot in the heat-and-humidity environment of a sauna.
Pros
- High strength-to-weight ratio, suitable for structural support applications
- The most affordable softwood option
- Easy to work with and widely available across North America
- Appropriate for interior finishing, packaging, and framing applications
Cons
- Low natural resistance to moisture and decay — not suitable for outdoor sauna use when untreated
- Requires regular treatment and maintenance to resist weathering and rot
- Prone to warping, splitting, and cracking under repeated temperature and humidity changes
- Shorter lifespan than cedar or thermowood in sauna conditions
- Untreated pine can ooze sap at sauna temperatures, creating sticky, difficult-to-clean surfaces
Nordic Spruce
Nordic Spruce (Picea abies), also known as Norway spruce or European spruce, is a premium wood choice for outdoor saunas that is well established in traditional Finnish and European sauna construction. Native to Northern, Central, and Eastern Europe, it is prized for its high density and firmly ingrown structure, which give it exceptional durability under the demanding conditions of a sauna environment.
Nordic Spruce maintains a beautiful light, near-white colouring throughout its lifespan and produces a subtle, therapeutic aroma that enhances the sauna session. Its natural terpene hydrocarbons provide inherent insect-repelling properties that are particularly valuable for outdoor installations. Note: Nordic Spruce should not be confused with North American spruce varieties, which do not share the same density, structural properties, or terpene profile as the European species.
Pros
- High density and firmly ingrown structure deliver exceptional durability and resistance to warping
- Beautiful light colouring that remains predominantly white throughout the wood's lifespan
- Natural terpene hydrocarbons provide built-in insect-repelling properties
- Subtle, therapeutic aroma that contributes positively to the sauna experience
- Long-established track record in traditional Finnish and European sauna construction
- Can be sustainably sourced from certified forests in Northern, Central, and Eastern Europe
Cons
- More expensive than most North American softwood alternatives
- Limited availability in many Canadian regions — typically requires import sourcing
- May require more maintenance than some other sauna woods to ensure long-term durability
- Less widely recognized in the North American market, which may affect resale perception
Choosing the Right Wood for Your Sauna
At Backcountry Recreation, we never compromise on material quality. Our saunas are built exclusively with the highest available wood grades, and we only use clear cedar — not knotty or select tight knot grades — as our standard. Our commitment to affordable luxury means our pricing already reflects exceptional value without the need for frequent discounting.
Now that you have a clear picture of how the major sauna wood types compare, the next decision is your heat source. For a full breakdown of the barrel sauna ownership experience — from construction to first use — Barrel Sauna Basics is a thorough starting point. If you're still weighing whether a barrel sauna is the right format for your property, 5 Reasons You Should Consider an Outdoor Barrel Sauna covers the key lifestyle and practical considerations. And for a deeper look at the performance and design nuances that make barrel saunas a unique experience, 10 Things You May Not Know About Barrel Saunas is worth reading before you finalize your choice.