Sauna room
A built-in cedar or hemlock sauna in a basement, bonus room or off the primary suite, on its own 240V circuit and vented to code.
Starting at $30K+
Signature Spaces
Spa Baths and Wellness Retreats in Bellevue: Sauna, Steam and Cold Plunge
A built-in sauna for 4 people runs about $12,000 to $20,000 installed (Sun Home Saunas, Dec 2025). Luxury custom saunas start around $50,000, and one recent project ran $80,000 (The Rye Record, Apr 2026). A full wellness build-out runs $250,000 to $500,000+ (The Rye Record, Apr 2026). In Bellevue and Eastside homes, Volcano Builders builds the room around the equipment: the 240V circuit, ventilation, waterproofing, steam, plunge plumbing and finishes. Our sauna rooms start at $30K+.
- WA License VOLCABI792C6
- Over 200 projects completed
- 4.9 Google rating
By appointment. Limited start dates.
See starting pricesKey numbers for a home sauna and wellness room
- 8 kW on 240V, 33.3 A, 40 A breaker
- Power for one common sauna heater (Harvia KIP80B, 250 to 425 cu ft room)Harvia KIP80B spec, read Oct 2026
- 7 ft
- Ideal sauna ceiling heightHaven of Heat, Feb 2026
- 50 cfm
- Bathroom exhaust, intermittent (or 20 cfm continuous)WAC 51-51-1505, effective Mar 2024
- About 875 lb
- Water in a 105 gallon plunge. Living area floors are designed for 40 psf, so a plunge on a wood floor gets an engineer's checkUSGS (8.33 lb per gallon); 2021 Seattle Residential Code Table R301.5
- 10 to 18 weeks
- On site for a spa primary bath, after design and permitsVolcano bathroom pricing guide, Oct 2026
What we build: sauna rooms, steam, cold plunge and spa baths
Sauna installation is one part of the job. We build the room around it: framing, the 240V circuit, ventilation, waterproofing, plumbing and finishes, in four configurations.
Spa primary bath with steam
Your primary bath rebuilt with a steam room, heated floor and soaking tub, with the option of a sauna off the bath.
Starting at $110K+
Signature spa bath tiers start at our Mid-Range primary bath plus steam.
Lower-level wellness suite
Sauna, steam room and cold plunge around one wet corridor in an existing basement. A gym zone is added from the Luxury tier.
Starting at $220K+
Wellness addition
The same suite built as new floor area, with ceiling height and floor framing designed for it.
Priced by consultation
See home addition pricingWho does what
Volcano Builders designs and builds the room around the sauna, steam and plunge equipment.
Volcano Builders
- Design, drawings and permit documents. Framing, 240V circuits, exhaust and fresh air, waterproofing and vapor barriers, plumbing to the steam generator and plunge, tile, stone, glass, millwork and finishes. One schedule and the city inspections.
Equipment makers
- Steam generator, plunge and chiller, chosen by model with you before framing and installed to the maker's instructions. Makers on the market include Harvia and HUUM for sauna heaters, ThermaSol and Mr. Steam for steam.
You
- One contact at Volcano and one schedule for the whole room.
Home sauna and wellness suite cost
Our sauna rooms start at $30K+, spa primary baths with steam at $110K+ and lower-level wellness suites at $220K+.
The configuration sets which rooms we build. The tier sets the scope and finish inside them.
Sauna room
Basic
Starting at $30K+
- Design and permit drawings, with heater, generator and plunge models chosen before framing (design fee listed separately)
- Cedar sauna with a Harvia or HUUM heater (A), a steam room with a 240V generator (B), or a cedar sauna, steam room and plug-in cold plunge (C)
- Dedicated 240V circuit for each heater or generator
- Exhaust fan sized to code and a sauna fresh air inlet
- Foil vapor barrier in the sauna, bonded waterproof membrane in every wet area
Includes a standard material allowance. Upgrades are priced from your selections.
Mid-Range Recommended
Starting at $55K+
- Two rooms planned together: sauna and steam, or sauna and a plug-in cold plunge
- Steam room with a 240V generator, sloped or vapor-tight ceiling and sealed glass door
- Linear drain and a bench in the steam room
- Heated floor on the wet side
- Clear grade cedar or hemlock with backlit benches
- Dimmable layered lighting on its own scene
Includes a standard material allowance. Upgrades are priced from your selections.
Luxury
Starting at $80K+
- Full suite: sauna, steam, cold plunge and a gym or recovery zone around one wet corridor
- Built-in cold plunge with a chiller, floor drain and tiled surround
- Dehumidification or an HVAC tie-in sized for the steam and plunge
- Large format stone or slab walls in the steam room
- Rubber gym floor over a level, reinforced subfloor
- Structural engineer review of floor loads under the plunge and stone
Includes a standard material allowance. Upgrades are priced from your selections.
Super-Luxury
Starting at $125K+
- Hinoki or thermally modified wood sauna with a glass front
- Larger steam room, with the generator sized to the room volume
- Stone plunge inset into the floor where the slab allows
- Recovery room with its own sound isolation and heated floor
- Smart controls for heater, steam and plunge from one panel or phone
- Slab stone, custom millwork lockers and towel warmers
Includes a standard material allowance. Upgrades are priced from your selections.
Spa primary bath with steam
Basic
Starting at $110K+
- Design and permit drawings, with heater, generator and plunge models chosen before framing (design fee listed separately)
- Cedar sauna with a Harvia or HUUM heater (A), a steam room with a 240V generator (B), or a cedar sauna, steam room and plug-in cold plunge (C)
- Dedicated 240V circuit for each heater or generator
- Exhaust fan sized to code and a sauna fresh air inlet
- Foil vapor barrier in the sauna, bonded waterproof membrane in every wet area
Includes a standard material allowance. Upgrades are priced from your selections.
Mid-Range Recommended
Starting at $165K+
- Two rooms planned together: sauna and steam, or sauna and a plug-in cold plunge
- Steam room with a 240V generator, sloped or vapor-tight ceiling and sealed glass door
- Linear drain and a bench in the steam room
- Heated floor on the wet side
- Clear grade cedar or hemlock with backlit benches
- Dimmable layered lighting on its own scene
Includes a standard material allowance. Upgrades are priced from your selections.
Luxury
Starting at $240K+
- Full suite: sauna, steam, cold plunge and a gym or recovery zone around one wet corridor
- Built-in cold plunge with a chiller, floor drain and tiled surround
- Dehumidification or an HVAC tie-in sized for the steam and plunge
- Large format stone or slab walls in the steam room
- Rubber gym floor over a level, reinforced subfloor
- Structural engineer review of floor loads under the plunge and stone
Includes a standard material allowance. Upgrades are priced from your selections.
Super-Luxury
Starting at $350K+
- Hinoki or thermally modified wood sauna with a glass front
- Larger steam room, with the generator sized to the room volume
- Stone plunge inset into the floor where the slab allows
- Recovery room with its own sound isolation and heated floor
- Smart controls for heater, steam and plunge from one panel or phone
- Slab stone, custom millwork lockers and towel warmers
Includes a standard material allowance. Upgrades are priced from your selections.
In a spa primary bath (B), each tier builds on our primary bathroom tier one step up: B Basic starts from our Mid-Range primary bath ($95K+) plus steam. See the primary bathroom tiers in our bathroom pricing guide.
Lower-level wellness suite
Basic
Starting at $220K+
- Design and permit drawings, with heater, generator and plunge models chosen before framing (design fee listed separately)
- Cedar sauna with a Harvia or HUUM heater (A), a steam room with a 240V generator (B), or a cedar sauna, steam room and plug-in cold plunge (C)
- Dedicated 240V circuit for each heater or generator
- Exhaust fan sized to code and a sauna fresh air inlet
- Foil vapor barrier in the sauna, bonded waterproof membrane in every wet area
Includes a standard material allowance. Upgrades are priced from your selections.
Mid-Range Recommended
Starting at $300K+
- Two rooms planned together: sauna and steam, or sauna and a plug-in cold plunge
- Steam room with a 240V generator, sloped or vapor-tight ceiling and sealed glass door
- Linear drain and a bench in the steam room
- Heated floor on the wet side
- Clear grade cedar or hemlock with backlit benches
- Dimmable layered lighting on its own scene
Includes a standard material allowance. Upgrades are priced from your selections.
Luxury
Starting at $425K+
- Full suite: sauna, steam, cold plunge and a gym or recovery zone around one wet corridor
- Built-in cold plunge with a chiller, floor drain and tiled surround
- Dehumidification or an HVAC tie-in sized for the steam and plunge
- Large format stone or slab walls in the steam room
- Rubber gym floor over a level, reinforced subfloor
- Structural engineer review of floor loads under the plunge and stone
Includes a standard material allowance. Upgrades are priced from your selections.
Super-Luxury
Starting at $575K+
- Hinoki or thermally modified wood sauna with a glass front
- Larger steam room, with the generator sized to the room volume
- Stone plunge inset into the floor where the slab allows
- Recovery room with its own sound isolation and heated floor
- Smart controls for heater, steam and plunge from one panel or phone
- Slab stone, custom millwork lockers and towel warmers
Includes a standard material allowance. Upgrades are priced from your selections.
In a lower-level wellness suite (C), every tier includes a sauna, a steam room and a cold plunge, built on our lower-level basement suite tier of the same name. Basic has a plug-in plunge. Mid-Range and up have a built-in plunge. Luxury and up add the gym zone.
Wellness addition By consultation. See home addition pricing
Starting prices include construction, project management, the sauna, steam and plunge equipment package and a standard finish material allowance for each tier.
Not included in starting prices: Design fees · City permit fees · WA sales tax · Appliances you buy · Finish upgrades beyond the allowance. We price these in writing if your project needs them.
Also priced in writing when the job needs it
Outdoor and barrel saunas (see Outdoor Living and Pool Houses). Utility service changes from Seattle City Light or Puget Sound Energy. Panel replacement, priced after a load calculation. Loose gym equipment, unless chosen as an allowance. Plunge water treatment and service plans. Any health outcome.
How we priced this
We started from published market costs, then added the room work we build around the equipment. Spa baths (B) start from our approved primary bathroom tiers plus steam. Lower-level suites (C) start from our approved lower-level basement suite tiers ($140K+ to $325K+) plus the sauna, steam and plunge.
| Market figure | Range | Source |
|---|---|---|
| Built-in indoor sauna, 4 person, installed | $12,000 to $20,000 | Sun Home Saunas, Dec 2025 |
| Built-in indoor sauna, 6 person, installed | $18,000 to $30,000 | Sun Home Saunas, Dec 2025 |
| Luxury custom sauna | From about $50,000; one recent project $80,000 | The Rye Record, Apr 2026 |
| Steam added to a planned bath | $10,000 | The Rye Record, Apr 2026 |
| Full wellness build-out | $250,000 to $500,000+ | The Rye Record, Apr 2026 |
| Large bathroom, Seattle design-build | $200,000 to $300,000+ | CRD Design Build, Jun 2026 |
| Premium built-in cold plunge, installed | $12,000 to $22,000 | LatestCost, Jan 2026 |
Prices checked October 2026. Sources: Sun Home Saunas, The Rye Record, CRD Design Build, LatestCost (links in Sources below).
Get a price for your room.
Book a consultation. We walk the space with you and price it in writing.
Related work: two primary bathrooms
These two primary bathrooms show the stone, frameless glass and waterproofing work our crews deliver.
Spa Master Bathroom with a Stacked Stone Shower Wall
See the stacked stone spa bathroom project
Luxury Primary Bathroom with Marble Slab Shower Walls, Redmond
See the marble slab shower project
Planning for later years
Of remodelers who did aging in place work, 87% installed grab bars, 78% built curbless showers and 52% widened doorways (NAHB, Q1 2025). In a spa bath we plan for them at the start: a curbless shower entry, a built-in bench, blocking in the walls for grab bars, and a wider door.
Room requirements for a sauna, steam room and cold plunge
A wellness room is built to code sections and maker specs, and each one sets a dimension, a circuit or a material on the drawings.
| Item | Requirement | Source |
|---|---|---|
| Sauna ceiling | 7 ft (84 in) ideal; 75 to 84 in for infrared | Haven of Heat, Feb 2026 |
| Sauna upper bench | Top of bench 36 to 42 in below the ceiling | Haven of Heat, Feb 2026 |
| Sauna door | 24 to 26 in wide, 72 to 78 in tall | Haven of Heat, Feb 2026 |
| Sauna walls | 2x4 studs at 16 in, R-13 batts, foil barrier facing in, seams lapped 2 to 3 in and taped with high temperature foil tape | Haven of Heat, Feb 2026 |
| Sauna heater, 8 kW example | 240V single phase, 33.3 A, 40 A breaker, 8 AWG wire | Harvia KIP80B spec, read Oct 2026 |
| Infrared sauna circuits | 2 person 240V 20 or 30 A; 3 person 30 or 40 A; 4 person 40 A | Peak Saunas, Mar 2026 |
| Sauna ventilation | 6 air changes per hour; inlet 50 to 100 mm (about 2 to 4 in) under or beside the heater; outlet low and far from the heater, twice the inlet size | Harvia, Mar 2026 |
| Steam ceiling | TCNA SR614 detail slopes the ceiling 2 in per foot. Mr. Steam calls for a slope when sessions run over 45 minutes. Above 8 ft needs a larger generator | TCNA SR614 via IMI, Nov 2024; Mr. Steam, Oct 2024 |
| Steam waterproofing | Continuous bonded membrane; floor sloped 1/4 in per foot to the drain | TCNA SR614 via IMI, Nov 2024 |
| Steam generator | 240V single phase on a dedicated breaker; drain line from the generator | Mr. Steam, Oct 2024 |
| Bath exhaust | 50 cfm intermittent or 20 cfm continuous, with a manual control in the room | WAC 51-51-1505, Mar 2024 |
| Cold plunge, plug-in example | 120V 15 A dedicated circuit, 105 gallons | Fortune review of Plunge All-In, Jun 2026 |
| Floor load | 40 psf live load in living areas; a 105 gallon plunge holds about 875 lb of water | 2021 SRC Table R301.5; USGS |
| Ceiling height, rooms | Habitable rooms 7 ft; bathrooms 6 ft 8 in; basement beams and ducts down to 6 ft 4 in | 2021 SRC R305.1 |
| Wet walls | Nonabsorbent surface to 6 ft above the floor | 2021 SRC R307.2 |
| Glass | Safety glazing in walls and doors of saunas, steam rooms and showers when the bottom edge is under 60 in | 2021 SRC R308.4.5 |
| Smoke alarms | At least 3 ft from the door of a bathroom with a tub or shower | 2021 SRC R314.3 |
Permits for a sauna, steam room or cold plunge
A wellness room needs permits in every city we work in. We prepare the drawings and our expediter submits the permit documents. City permit fees are the owner's cost.
- SeattleThe building permit exemption covers only minor repairs of $6,000 or less in any 6 month period with no structural change (SRC R105.2), so a wellness room needs a building permit. Seattle issues an electrical permit any time wiring is installed, altered or extended. Plumbing permits come from Public Health Seattle and King County.
- BellevueEvery shower needs a plumbing permit. New or moved circuits need an electrical permit. Extending ductwork needs a mechanical permit. Plan review applies when work adds load to beams or footings, and it may take about three weeks.
- Kirkland, Mercer Island, Sammamish, Issaquah and unincorporated King CountyThese cities use the MyBuildingPermit tip sheet, which states that tub and shower replacement requires a permit (TS-00, Jun 2026).
- MedinaBuilding permits go through the City of Medina Development Services. Electrical permits in Medina, Clyde Hill and Issaquah go through Washington L&I.
- Electrical codeWashington moves to the 2026 National Electrical Code for wiring on or after 31 Dec 2026 (WSR 25-23-069).
Timeline
| Phase | Duration | Source |
|---|---|---|
| Permit, Bellevue | Same day without plan review; about 3 weeks with plan review | City of Bellevue, Jan 2025 |
| Permit, Seattle | Goal 30 days; 75th percentile 64 days in City control for single family alterations | SDCI, goals as of Oct 2025 |
| Custom sauna build | 8 to 12 weeks per commission | Evermere Saunas, Bellevue, read Oct 2026 |
| Spa primary bath (B) | 10 to 18 weeks on site after design and permits | Volcano bathroom pricing guide |
Custom glass and stone add lead time. We choose sauna, steam and plunge models before framing, because some equipment will not fit narrow stairs or doors (The Rye Record, Apr 2026).
How a wellness room gets built
Book a consultation.
Call (206) 666-0412 or use the form below.
Site visit.
We measure the space and check the ceiling height, the electrical panel and the floor under the plunge.
Drawings, selections and a written, itemized proposal.
Heater, steam generator and plunge models are chosen before framing.
Build and inspections.
The city inspects each stage, and the room is covered by our warranty.
By appointment. Limited start dates.
Add-ons
Market figures, not Volcano prices. Each add-on is priced in your written proposal.
| Add-on | Market figure | Source |
|---|---|---|
| Steam added to a planned bath | $10,000 | The Rye Record, Apr 2026 |
| Built-in cold plunge in place of a plug-in unit | $12,000 to $22,000 installed | LatestCost, Jan 2026 |
| Full spectrum infrared unit | From $5,450 | Peak Saunas, Mar 2026 |
| Humidity sensors and automatic controls | $300 to $800 | Sun Home Saunas, Dec 2025 |
Google reviews of past Volcano projects
Bar's team completely transformed my outdated Seattle bathroom with their exceptional work. Their communication was excellent, keeping me informed every step of the way. The quality of their workmanship exceeded my expectations, turning my old bathroom into what I wanted. I highly recommend Bar and his team for any remodeling project; they're professional, efficient, and produce outstanding results.
Bar and his team did an excellent job on our condo bathroom renovation. From the start, Bar was easy to communicate with and quick to respond to all our questions and concerns. We couldn't be happier with the results and highly recommend Volcano Builders to anyone considering a remodel.
I had an amazing experience with Volcano Builders! Bar was incredibly kind, communicative, and made the whole process smooth. We completely redid the bathroom,new flooring, vanity, tub, and wall tiles, and it turned out fantastic. I'm so happy with their work that I'm already planning my second bathroom and hopefully the kitchen too. Highly recommend them to anyone looking for quality work and great service!
Warranty
License
WA License VOLCABI792C6. Over 200 projects completed. Our main office is in Bellevue.
Questions about home saunas, steam rooms and cold plunges
How much does it cost to put a sauna in my house?
A built-in indoor sauna for 4 people runs about $12,000 to $20,000 installed, and one for 6 people about $18,000 to $30,000 (Sun Home Saunas, Dec 2025). Luxury custom saunas start around $50,000, and one recent project ran $80,000 (The Rye Record, Apr 2026). Our sauna rooms start at $30K+, including the room around the sauna: the 240V circuit, ventilation and finishes. Design fees and city permit fees are listed separately.
Is it cheaper to build a sauna or buy one?
A kit is cheaper. A 4 x 6 ft cedar indoor kit lists at $2,728 without a heater (West Coast Saunas, Oct 2026). A built-in sauna adds the heater, a 240V circuit, ventilation, a foil vapor barrier and the finished room around it. That room is the part we build.
Is a sauna expensive to run at home?
A home sauna costs about $14 to $27 a month to run (Sun Home Saunas, Dec 2025). The heater sets the electrical load: an 8 kW heater draws 33.3 amps on a 40 amp breaker (Harvia KIP80B).
Does a sauna need a dedicated 240V circuit?
Most built-in saunas do. A traditional 8 kW heater runs on 240V with a 40 amp breaker (Harvia KIP80B). Infrared saunas for 2 or more people specify 240V circuits of 20 to 40 amps by size (Peak Saunas, Mar 2026). We size the circuit to the model you choose and check the panel with a load calculation.
Can a cold plunge go in a basement?
Yes, and a basement slab is the simplest base for one. A 105 gallon plunge holds about 875 lb of water (USGS, 8.33 lb per gallon). Living area floors are designed for a 40 psf live load (2021 Seattle Residential Code Table R301.5), so a plunge on a wood floor gets an engineer's check first. A built-in plunge also needs a floor drain and plumbing lines.
Does a steam shower need a permit in Bellevue?
Yes. Bellevue requires a plumbing permit for every shower and an electrical permit for any new circuit, and a steam generator needs a dedicated 240V circuit. Extending ductwork for the exhaust adds a mechanical permit. We prepare the drawings and our expediter submits the permit documents.
Can steam set off a smoke alarm?
It can when the alarm sits too close to the door. The 2021 Seattle Residential Code (R314.3) places smoke alarms at least 3 ft from the door of a bathroom with a tub or shower. We place the alarms and the exhaust fan on the drawings before framing.
How much does a full home wellness suite cost?
A full wellness build-out runs about $250,000 to $500,000+ (The Rye Record, Apr 2026). Our lower-level wellness suites start at $220K+ for a basement suite with a sauna, steam and a plug-in cold plunge.
Related guides and rooms
Signature Spaces
Tell us about the room and the space you have in mind.
By appointment. Limited start dates.
Prefer to call? (206) 666-0412. Mon to Fri 6am to 9pm, Sat and Sun 9am to 5pm.
Book a consultation for your wellness room
Four quick steps. Tell us about your project and we’ll reach out to discuss it and see if we’re the right fit.
Sources
Prices checked October 2026.
- Sun Home Saunas, indoor vs outdoor sauna installations, 10 Dec 2025: sunhomesaunas.com
- The Rye Record, home wellness studio costs, 13 Apr 2026: ryerecord.com
- CRD Design Build, cost of a bathroom remodel 2026, 30 Jun 2026: crddesignbuild.com
- LatestCost, cold plunge pool cost, 22 Jan 2026: latestcost.com
- Peak Saunas, infrared sauna electrical requirements, 5 Mar 2026: peaksaunas.com
- Harvia KIP80B heater spec, read 15 Oct 2026: thesaunaheater.com
- Harvia, ventilation in the sauna, updated 6 Mar 2026: support.harvia.com
- Haven of Heat, how to frame a sauna room, 15 Feb 2026: havenofheat.com
- Mr. Steam installation best practices, updated 4 Oct 2024: specialtyhardware.net
- IMI on TCNA SR614 steam room detail, 6 Nov 2024: imiweb.org
- Fortune, Plunge All-In review, 12 Jun 2026: fortune.com
- West Coast Saunas, 4x6x7 cedar indoor kit, read 15 Oct 2026: wcsaunas.com
- Evermere Saunas, read 15 Oct 2026: evermeresaunas.com
- USGS, facts about water, read 15 Oct 2026: usgs.gov
- WAC 51-51-1505, effective 16 Mar 2024: app.leg.wa.gov
- 2021 Seattle Residential Code, chapter 1: seattle.gov
- 2021 Seattle Residential Code, chapter 3: seattle.gov
- SDCI electrical permit, read 15 Oct 2026: seattle.gov
- SDCI permit performance, goals as of 1 Oct 2025: seattle.gov
- Public Health Seattle and King County, plumbing permits: kingcounty.gov
- City of Bellevue, building permit requirements, modified Jan 2025: bellevuewa.gov
- City of Bellevue, single family plan review, modified 24 Jan 2025: bellevuewa.gov
- MyBuildingPermit TS-00, 11 Jun 2026: mybuildingpermit.com
- City of Medina Development Services: medina-wa.gov
- Washington L&I, city electrical permits: lni.wa.gov
- WSR 25-23-069, NEC 2026 effective 31 Dec 2026: lawfilesext.leg.wa.gov
- NAHB aging in place, Q1 2025 (May 2025): eyeonhousing.org
- Volcano bathroom pricing guide: volcanobuilders.com
- Volcano basement pricing guide: volcanobuilders.com