Western Red Cedar for Saunas

The gold standard for sauna paneling: properties, sourcing, grades, and installation.

Western red cedar is the most popular sauna wood in North America. Naturally moisture-resistant, aromatic, and beautiful, it's the ideal choice for most residential saunas. This guide covers cedar selection, sourcing, grades, and proper installation techniques.

Why Western Red Cedar?

Naturally decay-resistant: Contains thujaplicin, a natural antimicrobial compound that resists rot, insects, and fungus without added chemicals.

Aromatic: Pleasant, distinctive smell that enhances the sauna experience. Never off-gasses toxic fumes.

Low thermal conductivity: Doesn't get as hot to the touch as other woods, making it comfortable for benches and walls.

Beautiful appearance: Warm, reddish-brown color. Weathers gracefully.

Workability: Easy to cut, nail, and finish. DIY-friendly.

Availability: Widely available in North America, usually affordable.

Grades and Quality

Cedar Grades

  • Clear: No knots, no defects. Premium grade. Most expensive ($8–12/sq ft).
  • Select: Few, small knots. High quality. Mid-range price ($5–8/sq ft).
  • Knotty (or standard): Visible knots, character marks. Still beautiful. Most affordable ($4–6/sq ft).

All grades are suitable for saunas. Choice depends on budget and aesthetic preference. Knotty cedar is perfectly functional and looks great.

Sizing and Profile

Typical sizes: T&G (tongue-and-groove) 1×4 or 1×6 boards are standard for sauna paneling.

Thickness: "1×" lumber is actually 3/4 inch thick (nominal size). This is adequate for sauna walls. Thicker boards (5/4) are available but unnecessary for interior use.

Moisture content: Critical. Cedar must be kiln-dried to 8–12% moisture content. Higher moisture content will warp, shrink unevenly, and create gaps.

Tongue-and-groove vs. square edge: T&G boards lock together and hide fasteners — preferred for appearance. Square edge boards are cheaper and simpler to install but require more finishing work.

Sourcing Cedar

Big Box Stores (Home Depot, Lowe's)

Convenient, widely available, consistent pricing. Typically Select or Knotty grades. Quality is reliable but may have occasional defects. Prices: $5–8/sq ft.

Local Lumber Mills

Higher quality, better pricing, access to specialty profiles. May require ordering in advance. If available locally, often better value than big box stores. Prices: $4–7/sq ft (depending on grade and mill).

Online Specialty Suppliers

Wide variety, competitive pricing. Requires shipping heavy lumber (significant cost factor). Best for small orders if shipping is included. Prices vary widely.

Tip: Buy slightly more than you calculate (5–10% extra) for waste, mistakes, and replacements later.

Installation Techniques

Orientation: Horizontal Installation

Boards are installed horizontally, starting at the bottom and working upward. This is the standard method. The boards run perpendicular to vertical furring strips on the walls. Male edge down is preferred (the tongue points downward) so water doesn't collect in the groove if moisture somehow appears.

Fastening

Use stainless steel or galvanized nails (never regular steel — will rust). 2.5-inch finish nails are typical. Nail through the tongue of T&G boards (the fastener is hidden by the groove of the next board). For square-edge boards, nail every 16 inches into furring strips.

Spacing and Sealing

Cedar naturally shrinks and expands with humidity changes. Allow 1/16" to 1/8" spacing between boards during installation to account for seasonal movement. Don't force boards together. This flexibility prevents cracking and warping.

Finishing

Cedar can be left unfinished (will gray over time) or sealed/stained. For interior saunas, many builders leave it natural. For exterior-facing wood, a water-resistant stain every 3–5 years extends cedar life.

Calculating Cedar Quantity

Formula: Wall area (in sq ft) ÷ usable coverage per board = boards needed.

Example: For a 6×8 sauna with 8-foot interior height:

  • Wall area: (6 + 6 + 8 + 8) × 8 = 224 sq ft
  • Coverage: 1×6 T&G boards cover ~5 sq ft per board (accounting for tongue)
  • Boards needed: 224 ÷ 5 = 45 boards (plus 10% waste = 50 boards)
  • 1×6 boards are 16 feet typical length, so 50 boards × 8 linear feet usable = 400 linear feet of cedar

Get a quote from your supplier using linear feet or board count. They'll calculate the exact amount needed.

Cedar vs. Alternatives

Hemlock: Cheaper than cedar, but not as decay-resistant. Requires more finishing.

Spruce: Light in color, less aromatic. Less durable than cedar.

Thermally modified wood: More expensive but superior durability and stability. See our TMW guide for details.

For most residential saunas, western red cedar is the best balance of cost, durability, and aesthetics.

Common Cedar Mistakes

  • •Not checking moisture content: Dry lumber is essential. Wet cedar will warp and gap.
  • •Forcing boards together: Allow space for expansion. Tight installation leads to cracking.
  • •Using regular steel nails: They rust. Use stainless or galvanized.
  • •Installing without vapor barrier: Humidity behind cedar will cause rot.

Ready to Source Your Cedar?

The Sauna Builder Toolkit provides material calculators, supplier recommendations, and detailed installation guides for cedar paneling.

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