Convert a Garage into a Home Gym with Sauna
Two-Car Garage → Home Gym with Sauna Room
Transform a two-car garage into a premium home gym with a dedicated sauna room, rubber flooring, proper ventilation, climate control, and a post-workout recovery area for the ultimate home wellness space.
Cost Range
$12,000 – $35,000
Timeline
4–10 weeks
Materials Cost
$16,340
Permits Cost
$750
Steps
Plan the Layout: Gym Zone vs Sauna Zone
Divide the garage into two distinct zones. The gym area takes up roughly 75% of the space (300 square feet in a standard two-car garage) and the sauna room occupies the remaining 25% (approximately 80-100 square feet, or about 6x8 feet to 8x10 feet). Position the sauna in a rear corner of the garage — this minimizes the impact on the gym floor space and keeps the sauna door away from the main workout area. Plan a small transition space between the gym and sauna for towel hooks, a bench, and a water station.
Estimated time: 3 days
Replace the Garage Door (Optional) and Insulate
For a gym-only conversion, you can keep the garage door and add an insulated garage door (R-12 to R-18). For a gym with sauna, replacing the garage door with a solid insulated wall is recommended because it improves climate control for both zones. Insulate all walls and the ceiling with fiberglass batts (R-13 walls, R-30 ceiling) or spray foam. The sauna room will get its own separate, heavier insulation layer in the next step.
Estimated time: 7 days
Frame and Build the Sauna Room
Frame a separate room within the garage using 2x4 studs. Insulate the sauna walls with mineral wool (R-13 minimum). Apply aluminum foil vapor barrier over the insulation with the shiny side facing inward — overlap seams and seal with high-temperature aluminum tape. Install furring strips over the vapor barrier, then line all walls and ceiling with tongue-and-groove western red cedar paneling. Build two-tier cedar benches. Install a 4.5-6 kW electric sauna heater on a dedicated 240V, 30-amp circuit. Add intake and exhaust vents and a tempered glass sauna door that swings outward.
Estimated time: 14 days
Install Gym Flooring
Cover the entire gym area floor with 3/4-inch interlocking rubber gym tiles. This is the single most important element of the gym build — rubber flooring protects the concrete, absorbs dropped weight impact, reduces noise, and cushions joints during standing exercises. For the area under a power rack or heavy lifting platform, consider 1-inch thick stall mats for additional durability. Budget $3 to $5 per square foot for quality rubber flooring. Do not use foam tiles — they compress under heavy equipment and deteriorate quickly.
Estimated time: 3 days
Install HVAC and Ventilation
Install a ductless mini-split system for the gym area — this provides both heating and cooling independent of the sauna room. A single-zone 12,000 BTU mini-split handles most two-car garages. Add a high-velocity wall-mounted fan for air circulation during intense workouts. The sauna room has its own ventilation (built-in vents from Step 3) and does not connect to the gym HVAC system — the sauna heater provides all the heat the sauna needs.
Estimated time: 5 days
Upgrade Electrical and Lighting
Your garage will need significant electrical upgrades to support both the gym and sauna. Install a subpanel if your main panel cannot handle the additional load. Required circuits: one 240V, 30-amp dedicated circuit for the sauna heater, one 240V circuit for the mini-split, and at least two 20-amp circuits for the gym area (outlets for treadmill, fan, sound system, etc.). Replace dim garage lighting with bright LED shop lights — install 4-6 fixtures for even, shadow-free illumination across the gym area. Add a dimmer-controlled light inside the sauna room.
Estimated time: 5 days
Install Gym Equipment
Set up equipment based on your training goals. A versatile starter setup: a power rack or squat stands with a barbell and plates, an adjustable bench, adjustable dumbbells, a pull-up bar (the power rack usually includes this), and a rubber floor area for bodyweight exercises and stretching. Add mirrors on one wall — they make the space feel larger and help with form checking. Mount a TV or tablet holder for workout programming. Add a Bluetooth speaker for music.
Estimated time: 3 days
Create the Recovery Zone and Final Details
Set up the transition area between the gym and sauna as a recovery zone. Add a wooden bench, towel hooks, a small shelf for water bottles and toiletries, and a floor mat. Optionally, install a simple cold water shower or outdoor hose connection near the sauna for post-sauna cold plunges. Add a small mini fridge near the gym entrance for cold water and recovery drinks. Mount a first aid kit on the wall. Add rubber door thresholds between the gym floor and the sauna room to create a clean transition.
Estimated time: 3 days
Materials
| Material | Est. Cost | Required |
|---|---|---|
| Garage Door Replacement Wall (framing, insulation, drywall) | $3,000 | Optional |
| Wall and Ceiling Insulation (fiberglass batts) | $1,200 | Required |
| Sauna Room Framing Lumber | $400 | Required |
| Sauna Mineral Wool Insulation | $300 | Required |
| Aluminum Foil Vapor Barrier and Tape | $100 | Required |
| Western Red Cedar Paneling (tongue-and-groove) | $1,000 | Required |
| Cedar Bench Lumber | $350 | Required |
| Electric Sauna Heater (4.5-6 kW) with Stones | $800 | Required |
| Tempered Glass Sauna Door | $500 | Optional |
| Interlocking Rubber Gym Floor Tiles (3/4 inch) | $1,200 | Required |
| Ductless Mini-Split HVAC System (12,000 BTU) | $3,000 | Required |
| Electrical Subpanel and Wiring (by licensed electrician) | $2,500 | Required |
| LED Shop Lights (6 fixtures) | $120 | Required |
| Power Rack or Squat Stands | $400 | Optional |
| Olympic Barbell and Weight Plates (300 lb set) | $500 | Optional |
| Adjustable Dumbbells | $350 | Optional |
| Adjustable Bench | $200 | Optional |
| Wall Mirrors (2 panels) | $150 | Optional |
| High-Velocity Wall Fan | $60 | Required |
| Mini Fridge | $150 | Optional |
| Sauna Accessories (bucket, ladle, thermometer) | $60 | Optional |
Permits
Building Permit
Required if replacing the garage door with a wall or making structural modifications. May not be required if only adding interior finishes and equipment.
$500
Electrical Permit
Required for the new subpanel, 240V sauna circuit, mini-split circuit, and gym electrical upgrades. Licensed electrician pulls this permit.
$250