FAQs: How to Build a Sauna

• How to Prepare for My Sauna Installation?

  How to Prepare for My Sauna Installation?
  CUSTOMER TO PROVIDE/PREPARE PRIOR TO SAUNA INSTALLATION

  Cedarbrook Sauna & Steam requires the following. Mostly likely your installer will require the same or need to do this work:

  Framed and studded walls and joists

  • A room with wood studs 16″ on center or wood nailers or plywood lined (can not nail cedar to steel studs), 7′ ceiling (or custom ceiling height) and R-13/19 insulation in the walls and ceiling

  Do I need to remove sheet rock?

  She rock does NOT need to be removed IF insulation is already in the walls. It’s easier to install sauna wall materials without drywall or sheetrock

  • 5/8″ – 1/2″ sheetrock as a one hour firewall (if local code requires). * Typically not required

  Rough Carpentry List:

  • Frame Sauna door RO (Rough Opening) to specs as quoted. Typical is a 24×82″ RO
  • Provide door jamb width (= the thickness of your existing wall, i.e. studs + cedar thickness on sauna interior + thickness of material on outside of sauna wall)
  • Framing for 4×6″ or 6×8″ intake and exit vents
    Vent size is dependent on heater size/wattage. If heater ≥ 9kW, then the larger vents are used
  • Flooring: Ceramic tiles, cement or other non-permeable flooring needs to be completed

  Electrical Preparations:

  • Any master disconnects, any pre-wiring of controls and all electrical connections for the heater, controls and lighting to be done by a certified electrician
  • Cedarbrook Sauna & Steam does NOT perform any electrical work or connections.

  Installer’s Work Area:

  Work progresses very well when the installer can cut and install materials within minimal walking distance. Please indicate to us the location and access to the sauna room. IMPORTANT: If cedar materials can NOT be stored and cut near the work site, then we need to know this.

  Thank you for working with us and feel free to contact us with any questions.

• Do I need permits to build a sauna?

  Electric Work is Best Performed by an Electrician

  Plenty of home owners do their own electrical work. Electrical preparation involves reviewing the electrical capacity of your service panel for available amps. For example 4×6 sauna room uses: 6kW sauna heater / 240V / 30 amp breaker / 10 gauge wire. Run electrical wire planning for the heater, lights, switch and external controls (optional).

  Electric saunas require a dedicated breaker and circuit and electric work. Safety first!

  Most home saunas require 4.5kW, 6kW or an 8kW sauna heater unless of course, you prefer wood-fired all-natural, then NO you wouldn’t any electricity necessarily. Though you might still want a light bulb, but lanterns work was well or the flash light on your phone. Wood-fired saunas in the city may sometimes encounter burn ban days, so consider your options.

  Typically, then sauna installations will require a dedicated 240 volt, 30 or 40 amp GFI-protected circuit. If you pull an electrical permit, it covers the sauna heater, light and switch and possibly a wall-mounted control panel, etc. Commercial saunas often have two 40 amp circuits (240 V).

  If you’re renovating a room and constructing a sauna in your home, and you do your own electrical permit. Then when you sell your home, you’ve covered your responsibility when you declare on Form 17 any work that was done without permits.

  Structural permits are usually NOT required

  Commonly, an outdoor sauna and structures of 120 sq. ft. or less do not require permits (in the U.S.). Some counties allow larger structures of up to 200 sq. ft. without permits. You may run into some problems if you put your sauna right on the property line you share with a neighbor, a parking strip or an access easement.

• I haven’t built sauna walls yet… what’s the maximum dimensions?

  An example sauna will best serve our question better …

  What’s the maximum dimensions 5×7′ sauna material package?

  FAQ: What’s the MAXIMUM stud-to-stud-to-joist measurement that fits this 5x7x7 Sauna Materials Package?

  Set your wall spans at:

  • WIDTH = 5′1⁵/₈″*
  • LENGTH = 7′1⁵/₈″
  • HEIGHT = 7′ ³/₄″ *

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  * Why are studs 1⁵/₈″ further apart than the sauna’s W x L ??

  Since ³/₄″ is the standard thickness of our standard cedar material and we’re adding it to two opposing walls. This reduces the room size by 1¹/₂″. But now consider we’re going to ship 5 ft and 7 ft benches, exactly. You want those benches to angle and drop into place without scratching your new soft cedar wood walls. So you want ¹/₈″ – ¹/₄″ for wiggle room.

  IMPORTANT! When maximizing coverage, center your boards on each wall leaving a mostly hidden gap in all corners — the trim kit provided will cover all corner gaps!

  Decrease wall spans by ¹/₂″, IF you selected ¹/₂″ material (this option only available IF WxL = 4×4, 4×6, 6×6, 6×8 or 8×8)

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  At these dimensions, the sauna benches will fit perfectly with ~¹/₈″ on each side* — NO need to trim your benches and cutting the cedar boards is minimal. At these dimensions, sauna benches will drop in at an angle without scratching your cedar walls

• How should I mount my sauna heater on the wall?

  

  Mount Sauna Heater 23″ Off the Floor

  Mount my sauna heater instructions

  ALLOWS CHECK YOUR SAUNA INSTALLATION INSTRUCTIONS FOR MOUNTING HEIGHT

  At right is an exposed sauna wall showing blocking to mount the sauna heater and the intake vent. This is our method for most wall-mounted sauna heaters with 50 lbs of rocks

  • Add blocking between your studs, so it’s ready for your installer or electrician to hang the sauna heater on the wall.
    NOTE: IF your sauna is a DROP 4.5, 7.5o 9 OR a Spirit 6 or 8 weighing about 150 lbs., consider doubling the studs!
  • Below the heater blocking is the intake vent opening. It sits right on the bottom plate of the wall. So very close to your hard floor. Generally, we make a 4×6″ vent opening IF the heater is 8kW or less, and 6×8″ vent opening if 9kW or bigger
  • The intake vent does NOT need to be under the heater. It can be within 3 feet. In small saunas ≤ 4×6, you can also vent under the door (ie., the gap)

  Later the sauna wall will be filled with R-13 insulation — excepting for the vent opening! Air will flow through the intake vent and into the sauna. The exit vent allows some air to exit the sauna. We cover the exterior of the vent with a grill and the intake with a sliding door.

  Sauna heater installation / Hanging a wall-mounted sauna heater

  Set your heater’s top mounting nuts at 23 inches off the hard floor (tile, cement, linoleum, etc.). This should leave between 6 ½–8″ from the hard floor to the bottom of the heater’s shroud.

• Sauna Venting | How to vent a sauna?

  Sauna Venting | We get these questions a lot:

  • Can I vent my sauna heat back into my house?
  • Or should I vent the sauna to the outside?

  

  It is best to vent the sauna heat back inside the house rather than to the outdoors. Why?

  • The main reason is that the barometric pressure outside is often different than indoors and this can create reverse flow bringing air from the outside in back through the exit vent. Also, you always want to minimize penetrations to the outdoors – it’s just more labor.
  • Though it might seem like a great way to add heat to your house, a sauna will add very little positive heat to your home as by design; it is meant to heat a small enclosed space and contain that heat.
  • Also FYI, the sauna will not add any significant moisture to the adjoining air space. Even when you ladle water over the sauna heater rocks you add very little actual humidity to the air. Saunas provide very dry air. The added humidity of a sauna ranges from 10-35%.

  Most importantly, the air coming into the sauna through the intake opening should be fresh and cooler than the heated sauna air

  Fresh air also affects the sauna heater’s thermostat and high limit sensors. Otherwise, the sauna heater may sense that the room is prematurely hot and thus shut the heater down before the desired temperature is reached. Fresh air air has slightly more oxygen but do not be concerned with oxygen levels as the sauna rooms are no where near air tight.

  Many saunas do just fine with a wide gap (about 1″) at the bottom of the door serving as the intake vent too. If you’re sauna is in an out building though, careful as small critters may find the warmth and shelter an inviting place to nest or warm up.

  We use sliders to control airflow and grills to cover the vents

  

  

  The cedar grills are beautiful, decorative and you can just as easily match heat registers in your house to the same affect. Sliders are important to control air flow. Many leave their intake vent fully open all the time and prefer a grill to cover the interior side of the intake vent ensuring constant intake air flow.

  Vents and grills do not include hardware as customers have different size nail guns or preferences on screws. We use 1 ½” galvanized (or stainless) finish nails.

  Air flow is very important for the sauna heater appliance

  Your sauna appliance needs fresh cooler air AND so do you! It ensures the air in the sauna does NOT get stuffy, especially as more bathers enter. So … 6 ½–8″ from the hard floor is plenty of space for the sauna heater to pull fresh cool air through through the intake vent AND some hot air will leave out the exit vent (up top, about 4-6″ from the ceiling on the wall) and fresh air with more oxygen can enter. The intake vent will be covered with this 4×6″ Sliding Door Sauna Vent Cover on the inside. (NOTE: bigger heaters > 8kW should get the bigger 6×8″ Sliding Door Sauna Vent Cover.)  And on the outside, you’ll cover the vent with this exterior sauna vent grill.

  

  

  

• How should I add my cedar paneling to the sauna ceiling and walls?

  How to Build a Sauna: Adding tongue and groove cedar paneling

  Begin on one side of your ceiling and nail your cedar panel boards perpendicular to the joists. Move across the ceiling until covered. As needed, cut a hole around the light box. Best if your light and switch are wet-rated.

  

  Next, nail the clear cedar paneling boards over the insulation and foil barrier. Nail your first row of tongue and groove wall boards to your studs horizontally, tongue up, groove down. Start from the bottom and move up. Generally, you only need nail the tongue after fitting it snugly over the prior row. This way the nail is hidden by the groove covering it. Vertical paneling is possible, but requires either plywood sheeting over the studs or some strategically spaced horizontal studs over the vertical studs.

  Add your cedar panel boards in rows, checking for level every 4th board or so. Fit the grooves over the tongues and continue up the wall. Along the way, you may need to cut for electrical junction boxes for lights, switches, etc. That’s the beauty of cedar, it’s soft to work with and cuts easily. Continue installing your panel boards until your insulated walls are covered. At the last row butting the ceiling, remember you need not be perfect. If you’re within a quarter inch you’re fine. The trim pieces will cover any gaps.

  See our videos and article here: How to Build a Sauna | Converting a Room to a Sauna

• How do you apply sauna foil vapor barrier?

  

  Tips when applying your sauna vapor barrier to your sauna

  A sauna vapor barrier is very important and a step that should never be skipped

  • A sauna foil vapor barrier is very important and a step that should never be skipped and do NOT use a substitute — it could melt at sauna temperatures. The foil will never melt and is odorless.
  • See our installation step: How to Build a Sauna: Foil to Reflect the Heat for installation tips. See our list of sauna foil sizes.
  • It’s worth noting that the sauna foil vapor barrier adds a R-1 value to your insulation factor, and acts as a reflective barrier, protecting your wood

  The techniques we follow are:

  • Start with the ceiling then the walls
  • Staple the foil vapor barrier to all interior surfaces; the wall and ceiling, not the floor. Overlap your wall foil over the 3″ of the ceiling, helping to keep rising heat near the ceiling

  A vapor barrier protects your walls from absorbing vapor. Some steam in your sauna is great to help bring on a sweat, but it creates humidity that should not seep into the walls. Venting a sauna into your house is fine.

  To best answer, you may want to see: How are home sauna kits built? | Explain Precut vs Prefab.

  Also we provide these sauna How-To articles plus a comparison of ALL the most common sauna kit options:

  • Home Sauna Kits | What Are the Differences Between Precut, Prefab, Modular & Infrared?
  • How to Build a Sauna | Converting a Room to a Sauna
  • How to Build a Freestanding Sauna | Setting up the DIY Prefab Modular Sauna Kit

• Must I remove drywall when installing a sauna?

  Generally, NO you do NOT need to remove drywall when installing a sauna build

  However, it’s important to mention you still ABSOLUTELY MUST …

  • Add insulation batting between studs in the walls — formaldehyde-free is best
  • Affix sauna foil vapor barrier over the drywall
  • Then, mark your studs so you know their location to affix T&G cedar paneling to the walls
  • Use longer nails to reach studs when attaching your cedar paneling to the walls and ceiling

  All said, of course you must still wire for the sauna heater, lights and switch and add intake and exhaust vents per your design

  We offer generic sauna plans on all of our sauna product pages. Just pick your sauna type (Modular PreFab Kit or Materials Package) and then choose a size, e.g. 4×6, 5×7, etc. You’ll see plans you can design on Step 1.

  So sometimes, it makes more sense to remove all drywall to accomplish the list of tasks above. And when removed, you have about 1 more inch of space. Not a big deal in larger saunas, still it may be helpful when installing a bench to have that extra inch.

  See our sauna videos regarding:

  • Must I remove drywall when installing a sauna? (on our site)
  • Vimeo: Must I remove drywall when installing a sauna? (same video on Vimeo platform)

• What’s required to make saunas ADA-compliant?

  ADA-compliant means your sauna meets the requirements to ensure those needing wheel chair access have the necessary room to maneuver

  An ADA-Compliant Sauna Requires

  • A 5×5′ turning radius — thus a 7×7′ sauna with 2 benches is basically the minimum size available
  • A 36″ wide door. We’ll build your door choice at 38×72″, 38×76″ or 38×82″ RO. ONLY the clad T&G and solid core doors can be built at 36″ width or we can work with you on some other choices
  • No threshold. A threshold acts as an impasse for wheelchairs and is NOT allowed

  RO = Rough Opening

  T&G = Tongue and Groove. This is the cedar panel cladding covering both sides of the door

• Do saunas require a floor drain?

  No, a floor drain is not common in a sauna

  Of course, if you are planning to take a cold quick rinse in your sauna, then yes, you will want one.

  Adding several ladles of water to your heater or to the walls is fine

  Yes, we encourage our sauna customers to add water to the HOT sauna rocks one ladle at a time. Sometimes, mixed with eucalyptus. Helps open the lungs and the steam will warm you to your bones and it just feels good.

  Also, a little splashing in the sauna is fine. It’s common in many sauna cultures to throw water on the walls too. The cedar will quickly dry it out. Cedar is very porous — increase the humidity in the sauna room.

  If you’re concerned about moisture remaining, then leave the sauna heater on an extra 20 minutes but you’ll see saunas contain the heat very well. All the moisture will evaporate in about 5-10 minutes. Sometimes, right before your eyes.

  Some of our customers have installed indoor sinks with a drain in the wall too!

• Sauna Bases | What are the base options for my outdoor sauna kit?

  Bases for outdoor saunas

  IMPORTANT: First note that the exterior size of our prefab modular saunas is 8″ wider and deeper than the size in the title. For example, a 5×7′ outdoor home sauna kit footprint measures 5’8′ x 7’8″.

  See our gallery of suitable sauna bases for our outdoor saunas

  Also please see our Video: Build Paver Base | Outdoor Sauna Kit

  The outdoor modular sauna kit will sit well on any of these bases:

  • Pour a concrete slab. Leave concrete surface bare or lay tile over the top.
  • Patio pavers: Tamp down gravel and lay patio pavers over.
  • Gravel with pressure treated wood works well also. In fact, if you know you will be relocating your sauna, it’s even easier to bring your base with you
  • If building on a wood deck (with air gaps between the slats) , then it’ll require a floor tray for insulation. Then put tile or sheet vinyl on the plywood for a water proof surface.

• How Large to Make My Sauna Base?

  

  How Large to Make My Sauna Base? … So Water Drips Outside the Sauna Floor

  At left, we use the example of a 5×7′ Sauna to show the proper dimensions such that rain landing on the sauna walls would drip away from the sauna floor.

  Basically it’s the sauna W x L + 6½″ in each direction. This calculation results because our beveled siding material is ¾″ thick. So twice = 1½″ from the footprint (5′8″ x 7′8″).

  See our page on Suitable Bases for Outdoor Saunas. Thanks.

What are the common mistakes when building a sauna?