The wood you choose for your sauna's interior is one of the most visible and experiential elements of the finished build. It affects aesthetics, aroma, thermal properties, durability, and cost. Western Red Cedar is the most popular choice for good reason — but it's not the only option, and depending on your budget and preferences, other species may serve you better.
This guide compares the major sauna wood species, their costs, durability, thermal properties, and sourcing so you can make an informed choice. Wood is just one piece of a larger build — our custom sauna design packages include a full materials specification, and you can start with our free design checklist.
| Sauna Wood | Cost/Sq Ft | Durability | Aroma | Best For |
|---|---|---|---|---|
| Western Red Cedar | $4–$8 | Excellent | Distinctive | Standard choice, walls & ceiling |
| Hemlock | $3–$6 | Very Good | Minimal | Budget alternative to cedar |
| Aspen | $2.50–$5 | Good | None | Budget builds, allergies |
| Aspen Wax/Char | $6–$10 | Very Good | None | Modern design, hypoallergenic |
| Alder | $4–$6 | Good | Mild | Pacific NW builds, warm tone |
| Spruce | $2–$4 | Fair | Slight | Kit builds, lowest cost |
| Basswood | $3–$7 | Fair | None | Premium benches (cool touch) |
| Thermally Modified | $6–$12 | Excellent | Minimal | Premium builds, max durability |
Read on for detailed breakdowns of each species, including sourcing tips, installation notes, and which wood works best for each part of the sauna (walls, ceiling, benches, trim).
Western Red Cedar is the most popular sauna wood for a reason: it delivers on every front. It's naturally resistant to moisture and decay, boasts a beautiful warm reddish color and distinctive aroma, and has excellent dimensional stability.
Availability: Tongue-and-groove (T&G) 1x4 or 1x6 boards are widely available at specialty lumberyards and online.
Cost: $4–$8 per square foot, depending on grade and source. Select or clear grades run higher; knotty cedar runs lower.
Properties: The wood contains natural oils that repel water and resist rot. Low density means it's lightweight and stays relatively cool to the touch compared to denser woods. The grain is attractive and ages to a silver-gray if left unsealed, or retains warmth if oiled.
Aroma: The distinctive cedar smell is one of the highlights of a cedar sauna. Many users cite the aroma as part of the therapeutic benefit. Some are sensitive to cedar oils — in those cases, aspen or hemlock is a better choice.
Our recommendation: Cedar is the standard for a reason. If your budget allows, use cedar for walls and ceiling.
Hemlock is an excellent alternative to cedar if you prefer a lighter appearance, don't want cedar's distinctive aroma, or are looking to save on cost. It's durable, stable, and grows in the same regions as cedar, making it readily available.
Cost: $3–$6 per square foot. Often $1–$2/sq ft cheaper than cedar.
Properties: Hemlock is slightly denser than cedar, which means it's a bit more durable under heavy use. It has excellent grain and a smooth, neutral appearance. It's naturally decay-resistant, though not quite as strong as cedar's resistance.
Aroma: Minimal scent. The wood smells clean and neutral — some users prefer this to cedar's strong aroma.
Appearance: Light, cream-colored with subtle grain. Doesn't develop the warm orange patina of cedar. This appeals to minimalist or Scandinavian design preferences.
Best for: Builders who want cedar-quality durability with a lighter aesthetic and no strong aroma.
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Aspen is a softwood that's lightweight, soft to the touch, and virtually free of resinous compounds. It's an excellent choice if you're sensitive to cedar oils or looking to minimize cost.
Cost: $2.50–$5 per square foot. The most affordable option among hardwood alternatives.
Properties: Aspen is soft — so soft that it won't absorb and hold heat the way denser woods do. This makes it particularly good for benches where you want wood that stays cool to the touch. For walls, the softness means it's more susceptible to dents and damage over time, but in a home sauna with moderate use, this is rarely an issue.
Durability: Aspen is less naturally rot-resistant than cedar or hemlock. In a well-sealed sauna with proper ventilation and moisture management, it works fine. In a humid environment with poor drying, it may develop issues sooner than other species.
Aroma: No resin, no distinct scent. Clean and neutral. Ideal if cedar oils trigger allergies or sensitivities.
Appearance: Pale, creamy white. Doesn't darken or develop character over time the way cedar does.
Best for: Budget builds, users with cedar sensitivity, and anyone prioritizing soft-to-touch wood for benches.
Aspen wax (sometimes called "wax aspen") and aspen char are thermally modified versions of aspen that have been heat-treated to improve dimensional stability, moisture resistance, and durability. The treatment darkens the wood — "wax" produces a warm brown tone, while "char" creates a deeper, almost espresso color.
Cost: $6–$10 per square foot. Significantly more than raw aspen but comparable to other thermally modified options.
Properties: The thermal modification removes moisture-attracting sugars and resins, making the wood far more dimensionally stable than untreated aspen. It retains aspen's key advantage — low thermal conductivity, meaning it stays cool to the touch — while fixing aspen's main weakness: susceptibility to moisture damage.
Best for: Builders who want aspen's hypoallergenic, cool-touch properties with significantly better durability. The darker color works well in modern sauna designs. Popular for benches and accent walls.
Alder is common in Pacific Northwest builds and offers a warm, reddish-brown tone that deepens with age and heat exposure. It's moderately priced and readily available in the western US.
Cost: $4–$6 per square foot. Similar to hemlock, sometimes slightly higher.
Properties: Alder is a hardwood with moderate density — heavier than aspen but lighter than oak. It's reasonably moisture-resistant and has good dimensional stability. The grain is subtle and even.
Aroma: Mild, slightly sweet. Not as distinctive as cedar but pleasant.
Best for: Builders in the Pacific Northwest who want a warm, distinctive look without cedar's strong aroma. Works well for walls and ceiling; pair with aspen or basswood benches for a mixed-species build.
Spruce is commonly used in sauna kits and barrel saunas because it's inexpensive and widely available. It works, but comes with trade-offs in durability compared to cedar, hemlock, or aspen.
Cost: $2–$4 per square foot. Cheapest of the commonly available species.
Properties: Spruce is softer than hemlock but has moderate decay resistance. The wood is lighter in color and has a neutral appearance. It does contain some resin, so it's not ideal for users sensitive to wood oils.
Durability: Spruce is more susceptible to moisture damage over time. In barrel saunas and prefab kits (where structural integrity isn't critical and replacement panels are inexpensive), it's acceptable. For a permanent custom build, better options exist at slightly higher cost.
Best for: Budget-conscious kit-style builds where wood replacement is anticipated.
Basswood is exceptionally soft and light-colored, making it popular for sauna benches where users want wood that doesn't absorb heat. It's less common for walls but can work in specialty builds.
Cost: $3–$7 per square foot. Similar to or slightly above cedar, but limited availability.
Properties: Basswood is very low density, which means it stays cool in your hand and conducts heat poorly. This is ideal for benches — you won't burn your legs. It has no resin, so there's no distinct aroma.
Durability: Basswood is not naturally rot-resistant. For benches in a well-ventilated sauna, it's fine. For walls, you'd need aggressive vapor barrier work to prevent long-term issues.
Appearance: Pale, almost white. Doesn't develop patina. Very clean, Scandinavian aesthetic.
Best for: Premium bench construction where you want maximum comfort and temperature control.
Thermally modified wood (often called heat-treated wood) is lumber that's been kiln-heated to extremely high temperatures, improving stability, moisture resistance, and durability. It's gaining traction in European sauna design and is becoming more available in North America.
Cost: $6–$12 per square foot. More expensive than cedar, but offers superior performance.
Properties: The heat treatment removes volatile organic compounds and increases dimensional stability dramatically. The wood resists warping, cupping, and moisture absorption far better than untreated species. It's naturally more durable than cedar.
Appearance: Darker color than untreated wood — often browns or blacks depending on the treatment intensity. This can be beautiful in modern sauna designs.
Durability: Excellent. The treatment makes the wood less susceptible to rot and mold. Lifespan can exceed 20+ years with proper maintenance.
Best for: Long-term builds where durability and minimal maintenance are priorities. Growing choice for premium custom saunas.
Pine: Pine is cheap and tempting, but contains high levels of resin that leaches and oozes at sauna temperatures. The resin coats your skin and the walls become sticky. Avoid.
Pressure-treated lumber: Treated wood contains chemicals that offgas at high temperatures, releasing toxic fumes. Never use it inside a sauna.
Plywood or MDF: The adhesives in engineered wood offgas in heat and humidity. They deteriorate rapidly in a sauna environment.
Any wood with stains, sealants, or finishes: These offgas in heat. Sauna wood should be raw or finished with only food-grade mineral oil or sauna wax.
Big box stores (Home Depot, Lowe's): Carry standard cedar T&G. Selection is limited, but prices are reasonable for average-grade material. Quality varies.
Local lumberyards: Often stock better grades of cedar, hemlock, and specialty woods. They can source on request. Prices are often better on bulk orders.
Sawmills and specialty dealers: If you have a local mill, you can often get higher-quality wood at better prices, especially in bulk. Building relationships with suppliers can lead to wholesale discounts.
Online specialty retailers: Amazon, Etsy, and dedicated sauna supply sites carry T&G boards. Shipping costs add up for bulky material, so compare total cost carefully.
Best practice: Buy kiln-dried wood with 8–12% moisture content. Check for knots, cracks, and warping. Inspect a few boards before committing to a full order.
Walls & Ceiling: Cedar or hemlock are the standard choices. Both provide good durability, appearance, and aroma (or lack thereof, for hemlock). Aspen works if budget is tight.
Benches: Cedar, hemlock, redwood, or basswood. If you want benches that stay cool to the touch, choose basswood or aspen. Cedar and hemlock are warmer but more durable.
Doorframe & Trim: Match the walls for aesthetic continuity. Cedar is standard.
Regardless of which wood you choose, proper installation maximizes lifespan and performance.
Orientation: Install all T&G boards horizontally (running perpendicular to the wall studs). This creates a more attractive pattern and allows water to run down the boards instead of sitting in grooves.
Male-side-down rule: The tongue (male edge) should point downward, the groove (female edge) upward. This prevents water from sitting in the groove if condensation drips from above.
Fastening: Use brad nails or stainless steel screws driven through the tongue (blind fastening). This hides fasteners and prevents rust marks.
Furring strips: Install boards on 1/4–1/2 inch furring strips over the vapor barrier. This creates an air gap that allows any trapped moisture to dry.
No finish: Leave wood raw or finish with food-grade mineral oil or sauna wax only. Never use polyurethane, varnish, stain, or any finish that offgasses.
For a standard 6×8 sauna with 7-foot ceilings, here's the breakdown:
Total for a 6×8 sauna: approximately 250–300 sq ft of T&G boards plus 40–60 board-feet of bench stock. At cedar prices ($4–$8/sq ft), that's $1,400–$3,000 for walls/ceiling plus $200–$500 for benches.
Use our materials estimator for a more precise calculation based on your specific dimensions.
| Species | Cost/Sq Ft | Durability | Aroma | Best For |
|---|---|---|---|---|
| Western Red Cedar | $4–$8 | Excellent | Distinctive | Standard choice |
| Hemlock | $3–$6 | Very Good | Minimal | Budget alternative |
| Aspen | $2.50–$5 | Good | None | Budget & sensitivity |
| Spruce | $2–$4 | Fair | Slight | Kit builds |
| Alder | $4–$6 | Good | Mild | PNW builds, warm tone |
| Basswood | $3–$7 | Fair | None | Premium benches |
| Aspen Wax/Char | $6–$10 | Very Good | None | Modern, hypoallergenic |
| Thermally Modified | $6–$12 | Excellent | Minimal | Premium builds |
For most builds, Western Red Cedar is the best choice. It balances durability, appearance, aroma, cost, and availability. The distinctive smell is part of the sauna experience for many users.
If you're budget-conscious, hemlock delivers nearly cedar-quality durability at a lower price. If you have cedar sensitivity, aspen or hemlock are good alternatives. If you're building for decades of durability and don't mind the premium, thermally modified wood is worth exploring.
Whatever you choose, buy kiln-dried wood, install it with proper orientation and fastening, and never paint or seal the interior wood. A well-chosen wood and properly maintained sauna will serve you beautifully for 20+ years.
Western Red Cedar is the best overall choice. It's naturally rot-resistant, dimensionally stable, has a pleasant aroma, and stays relatively cool to the touch. Hemlock is the best budget alternative. For people sensitive to cedar oils, aspen or hemlock are good choices.
No. Pine contains high levels of resin that leaches and oozes at sauna temperatures (160–200°F+). The resin coats your skin and makes the walls sticky. Also avoid pressure-treated lumber, plywood, and MDF — they offgas toxic compounds in heat.
Aspen wax is thermally modified aspen that's been heat-treated to improve stability and moisture resistance. The treatment darkens the wood to a warm brown ("wax") or deep espresso ("char"). It combines aspen's hypoallergenic, cool-touch properties with significantly better durability.
A standard 6×8 sauna needs roughly 250–300 sq ft of T&G boards for walls and ceiling, plus 40–60 board-feet of 2× stock for benches. Add 10–15% for waste. At cedar prices, total wood cost runs $1,400–$3,500.
No. Leave sauna wood raw or finish only with food-grade mineral oil or sauna wax. Polyurethane, varnish, stain, and other finishes offgas at sauna temperatures and can release harmful fumes. The wood will naturally darken and develop character over time.
12 decisions that determine how well your sauna performs — insulation, bench height, heater sizing, ventilation, and more.
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