DIY Sauna Kits — Build Your Own Sauna Room

Complete DIY sauna room kits with everything you need to turn a framed, insulated space into a fully functional sauna. Choose from two kit lines: Finnish Sauna Builders pre-cut custom kits in 21 room sizes with three premium wood options and a Harvia heater included, or our cedar room liner kits in traditional electric and infrared configurations. Every kit ships free.

Finnish Sauna Builders — Pre-Cut Custom Sauna Room Kits

Finnish Sauna Builders kits are complete pre-cut sauna packages built to an 8-foot ceiling height — the proper height for authentic Finnish sauna performance with even heat distribution and good löyly (steam). Each kit includes all interior components precisely cut and tailored to your room dimensions: tongue-and-groove wall and ceiling boards, 20"-deep bench boards with supports in your choice of bench configuration, an all-glass sauna door with wood handles, ergonomic backrests, a headrest, duckboard flooring, foil vapor barrier, upper and lower vent grills, a marine-grade vapor-proof sauna light, a traditional sauna bucket with liner and ladle, a thermometer, and a Harvia heater with stones. You provide the framing, insulation, electrical wiring, and exterior wall covering.

Available in 21 room sizes from 3'x4' up to 8'x9', each available in three wood types:

Western Red Cedar — The classic sauna wood. Grade A, knot-free, naturally moisture- and decay-resistant, cool to the touch during sessions, with rich reddish-brown tones. Browse our full cedar sauna wood selection.

Thermo Aspen / Alder — Thermally modified at 419°F+ for a deep, rich color with dramatically enhanced durability and dimensional stability. A modern, sophisticated look with superior performance indoors or outdoors. See our thermo-aspen and alder wood collections.

Thermo Poplar — Thermally modified at approximately 374°F for improved dimensional stability and humidity resistance with a warm, rich tone. A chemical-free process that's ideal for indoor saunas at a competitive price point.

Finnish Sauna Builders sizes: 3'x4', 4'x4', 4'x5', 4'x6', 4'x7', 4'x8', 5'x5', 5'x6', 5'x7', 5'x8', 6'x6', 6'x7', 6'x8', 6'x9', 6'x10', 7'x7', 7'x8', 7'x9', 7'x10', 8'x8', and 8'x9'. Need a size not listed? Request a custom sauna quote.

Cedar Room Liner Kits — Traditional Electric

Our traditional cedar room liner kits are designed for a standard 7-foot ceiling height and come in A+ clear, kiln-dried Western Red Cedar tongue-and-groove paneling. Each kit includes a stainless steel electric sauna heater with built-in timer, an insulated cedar door with tempered glass window, upper and lower benches (19" deep), two vapor-proof sauna lights, and interlocking PVC floor tiles. Heater wattage is matched to room volume — smaller rooms get a 4–5 kW heater, mid-size rooms get 5–6 kW, and larger rooms get 7.5–9 kW.

Available in 11 sizes: 4'x4' (4 kW), 4'x5' (5 kW), 4'x6' (5 kW), 5'x5' (5 kW), 5'x6' (5 kW), 5'x7' (5 kW), 6'x6' (6 kW), 6'x7' (6 kW), 6'x8' (7.5 kW), 7'x8' (9 kW), and 8'x8' (9 kW). All require a 240V dedicated circuit.

Cedar Room Liner Kits — Infrared

Our infrared cedar room liner kits use the same premium Western Red Cedar paneling, benches, door, lighting, and flooring as the traditional kits but swap the electric heater for low-EMF infrared heater panels with a digital controller. Infrared panels deliver gentle radiant warmth at lower air temperatures (typically 120–150°F) and plug into a standard 120V household outlet — no electrician required for most installations.

Available in 4 sizes: 4'x4' (1,800W), 4'x5' (2,400W), 4'x6' (3,600W), and 5'x5' (3,600W).

Finnish Sauna Builders vs. Cedar Room Liner Kits

The two kit lines serve different builders and budgets. Finnish Sauna Builders kits are a premium option with three wood choices, an all-glass door, Harvia brand heaters with multiple model options (including WiFi models), duckboard flooring, backrests, a bucket and ladle set, and an 8-foot ceiling designed for proper Finnish heat stratification. They're ideal for builders who want an authentic Finnish sauna experience with high-end materials and the flexibility to choose their exact wood species and heater.

The cedar room liner kits are a straightforward, all-in-one package at a lower price point — Western Red Cedar only, 7-foot ceiling, with a basic stainless steel heater (traditional) or infrared panels. They're a great fit for budget-conscious DIY builders who want quality cedar paneling and a reliable heater without the premium upgrades. For a deeper look at how ceiling height affects sauna performance, read our Finnish Rule of 230 guide.

How to Build a Sauna With a DIY Kit

Both kit types install into a pre-framed, insulated room. Here's the general process:

1. Frame and insulate your room. Build a standard 2x4 stud wall frame to your chosen kit dimensions. Insulate with R-13 fiberglass batts in the walls and R-19 in the ceiling. Cover the insulation with a foil vapor barrier (foil side facing into the sauna). Finnish Sauna Builders kits include the foil vapor barrier; cedar liner kits do not. Do not use plastic vapor barriers — they can melt at sauna temperatures.

2. Install the wall and ceiling paneling. Tongue-and-groove boards interlock and nail directly to the studs. Start from the bottom and work up. Walls first, then ceiling.

3. Mount the benches. Each kit includes pre-cut bench frames and bench boards for upper and lower seating. Finnish Sauna Builders kits offer multiple bench configurations to choose from.

4. Hang the door and lights. Finnish Sauna Builders kits include an all-glass door (28" x 80" rough opening). Cedar liner kits include an insulated cedar door with tempered glass window.

5. Install the heater. For traditional kits, mount the electric heater and have an electrician wire the 240V circuit. For infrared kits, mount the panels per the layout diagram and plug into a 120V outlet.

Most builders complete the entire installation in a weekend. Our team is available at (360) 233-2867 if you have questions during the build.

Where to Install a DIY Sauna

These kits work in any space where you can frame an insulated room: a spare bathroom, basement corner, garage, walk-in closet, or dedicated room addition. Some customers build the framed room inside an existing shed or outbuilding for a backyard sauna. The smallest kit (3'x4') fits in spaces as tight as a large closet, while the largest (8'x9') can seat 6+ people comfortably. For outdoor builds with a weatherproof enclosure, explore our outdoor DIY sauna kits.

Upgrade Your Build

Starting with a DIY kit doesn't mean you're locked into what's in the box. Many builders upgrade the heater to a higher-end unit like a Harvia KIP with WiFi or an HUUM DROP for smartphone control. You can also add red light therapy panels to any traditional sauna build, or browse our full sauna wood selection if you want to source individual boards for a fully custom project. Need help sizing a heater to your room? Use our sauna heater size calculator.

Frequently Asked Questions

Do the kits include a sauna heater?

Yes. Finnish Sauna Builders kits include a Harvia heater with stones — you choose from multiple Harvia models including the KIP, Cilindro, Spirit, and Virta in both WiFi and built-in control versions. The cedar room liner traditional kits include a stainless steel electric heater with built-in timer, and the infrared kits include infrared heater panels with a digital controller.

What ceiling height do I need?

Finnish Sauna Builders kits are designed for an 8-foot ceiling, which is the recommended height for proper Finnish sauna heat performance (see the Rule of 230). The cedar room liner kits are designed for a 7-foot ceiling. Contact us if you need a custom ceiling height — Finnish Sauna Builders can accommodate non-standard dimensions.

Do I need a permit to build a sauna in my house?

Permit requirements vary by municipality. Most residential sauna builds that don't change the home's footprint or add new plumbing don't require a building permit, but the 240V electrical work for a traditional heater typically requires an electrical permit and inspection. Infrared kits that plug into a standard 120V outlet generally don't trigger permit requirements. Check with your local building department.

Can I install a DIY sauna kit on a concrete floor?

Yes. The cedar liner kits include interlocking PVC floor tiles that sit directly on concrete. Finnish Sauna Builders kits include duckboard flooring in matching wood. Neither requires a subfloor. If your concrete is below grade (basement), make sure you have a vapor barrier under the slab or apply a concrete sealer to prevent moisture migration.

What kind of insulation should I use?

Standard R-13 fiberglass batts in the walls and R-19 in the ceiling. Cover the insulation with a foil vapor barrier (foil-faced kraft paper or aluminum foil), with the foil facing into the sauna room. The foil reflects radiant heat back into the sauna and prevents moisture from reaching the insulation.

What's the difference between the wood types?

Western Red Cedar is the traditional North American sauna wood — aromatic, naturally decay-resistant, cool to the touch, and available at the widest range of price points. Thermo Aspen/Alder is thermally modified hardwood with a deep, dark color and exceptional dimensional stability — it won't warp, shrink, or absorb moisture the way untreated wood can, and it works indoors or outdoors. Thermo Poplar is a mid-range thermally modified option with a warm tone and good humidity resistance, ideal for indoor saunas. For more on sauna wood options, visit our sauna wood guide.

Learn More

For step-by-step build guidance, sizing help, and heater comparisons, explore our Sauna Learning Center. For a fully custom build with specific dimensions and materials, try our custom sauna design and quote service. Ready to start your build? Call or text our team at (360) 233-2867.

Shop more: Outdoor DIY Sauna Kits · Electric Sauna Heaters · Infrared Heater Panels · Sauna Wood · Complete Heater Packages · All Saunas