Floor loading and impact
A rack of plates, a person and a dropped bar produce a load and an impulse that most upper-floor slabs were never designed for. This is verified by a structural engineer, in writing, before anything else.
| Zone | Static load | What it needs | ₹ per sq ft for the floor |
|---|---|---|---|
| Cardio | 3 – 4 kN/m² | Rubber tile 8–12 mm over a level screed | ₹180 – 380 |
| Resistance machines | 4 – 5 kN/m² | Rubber tile 12–15 mm | ₹280 – 480 |
| Free weights | 5 – 7.5 kN/m² | Rubber 20–30 mm with an isolation layer | ₹450 – 900 |
| Olympic lifting platforms | 7.5 – 10 kN/m² plus impulse | Floating platform on resilient pads, timber insert | ₹1,200 – 2,400 within the platform |
| Functional turf | 4 – 5 kN/m² | Turf over shock pad, sled-rated | ₹420 – 780 |
| Studio — yoga, dance, spin | 3 – 4 kN/m² | Sprung timber or vinyl over a resilient layer | ₹380 – 1,100 |
Loads are indicative design values for the occupied zone. A structural engineer must confirm the actual slab capacity on any floor above ground.
The slab decides the layout before the equipment does
Ventilation, which most gyms get wrong
- Design at 10–15 litres per second per person, against the 8–10 used for an office. Exercising bodies produce three to six times the CO₂ and considerably more moisture.
- Cooling is a separate calculation from ventilation. Forty people exercising produce roughly 14–20 kW of sensible heat, plus the equipment. A gym cooled like a retail space will be unusable by 7pm.
- Move the air at floor level. High-level supply alone leaves a dead layer over the free-weight area, which is exactly where the effort is.
- Extract the changing rooms hard, at 10–15 air changes an hour, and keep them negative relative to the gym floor so odour does not migrate.
- Humidity matters as much as temperature. Keep relative humidity below 60% or the floor gets slippery, the mirrors fog and the equipment corrodes.
- Put a CO₂ sensor in the studio. A forty-person spin class in a closed room will exceed 1,500 ppm within twenty minutes on a code-minimum ventilation rate.
Zoning and sightlines
- Cardio at the front, free weights at the back. Cardio users want a view and light; lifters want a wall and mirrors and do not want to be the first thing a visitor sees.
- Put the noisiest zone furthest from the entrance and from any neighbour. Free weights and functional training generate both impact and volume.
- Studios need acoustic separation, not a partition. A spin or HIIT studio adjacent to a yoga room needs a double-stud wall with a break, a sealed door and no shared ceiling void.
- Reception should see the floor. Supervision, safety and member experience all improve when the desk has a line of sight down the main aisle.
- Circulation of 1,200 mm minimum between equipment rows, 1,500 mm where a machine has a moving part that projects.
- Mirrors on the lifting wall, not everywhere. A fully mirrored gym is disorienting and doubles the apparent crowd. Full-height on the free-weight and studio walls, nowhere else.
Changing rooms, which decide the membership
Members tolerate old equipment. They cancel over changing rooms. Provision is a business decision and it is routinely under-budgeted.
| Element | Provision | Note |
|---|---|---|
| Lockers | 1.2 per peak-hour member | 300 × 450 × 500 mm; the commonest under-provision in the sector |
| Showers | 1 per 25 peak-hour members | Individual cubicles with a dry changing space, not a communal row |
| Bench length | 900 mm per 8 lockers | Someone is always sitting where someone else needs to reach |
| Floor | R11 wet slip rating, coved to the wall | A wet changing room floor is the highest liability area in the building |
| Ventilation | 10 – 15 air changes an hour, negative to the gym | Odour control is entirely a ventilation problem |
| Hot water | 40 – 55 litres per shower at peak | Size for the peak hour, not the daily total |
| Power points | 1 per 4 lockers at bench height | Hairdryers, phones, shavers |
Every gym owner wants to spend the budget on the free-weight area. The members who renew are the ones who had a locker, a shower with hot water and somewhere dry to put their bag.
Greenbox commercial fit-out lead
Rates by format
| Format | ₹ per sq ft, ex-GST | Typical area | Programme |
|---|---|---|---|
| Society or apartment gym | ₹1,400 – 2,000 | 600 – 1,500 sq ft | 4 – 7 weeks |
| Boutique studio — yoga, pilates, spin | ₹1,700 – 2,600 | 1,000 – 2,500 sq ft | 6 – 10 weeks |
| Neighbourhood commercial gym | ₹1,600 – 2,400 | 2,500 – 6,000 sq ft | 8 – 12 weeks |
| Premium fitness club | ₹2,400 – 3,200 | 6,000 – 15,000 sq ft | 12 – 18 weeks |
| CrossFit or strength box | ₹1,500 – 2,300 | 2,000 – 5,000 sq ft | 6 – 10 weeks |
Ex-GST. Includes civil, flooring, ceilings, mirrors, changing rooms, MEP coordination and finishes. Excludes all fitness equipment.
Lighting, mirrors and the things members notice
Fitness interiors are photographed constantly by the people who use them, and the lighting is what decides whether that works in your favour. Six specifications cover it.
- 400–500 lux on the gym floor, 300 in studios, with the studios dimmable to 10% for yoga and restorative classes.
- Never put a downlight directly above a bench or a mat. Anyone lying down is looking straight into it. Light the walls and let the floor take the reflected component.
- 4000K on the main floor, 2700–3000K in studios and changing rooms. Cool light reads as energetic; warm light is what people want when they are recovering or changing.
- CRI 90 at the mirrors. Members check their form and their appearance in the same glance, and poor colour rendering makes a good gym feel cheap.
- Mirrors on a ventilated batten, 6 mm, copper-free, safety-backed. A gym mirror bonded directly to a damp wall will spot at the edges within two years and is a safety issue if it breaks.
- Mirror height 300 mm off the floor to 2,400 mm. Starting at floor level means the bottom band is permanently scuffed by equipment and shoes.
Where we work
We design gyms and fitness studios nationally and build them across Mumbai, including society clubhouse gyms. For structural limits in older Mumbai buildings, noise complaints from neighbouring flats and local rates, see gym interior designers in Mumbai. Related formats are on salon and spa interior design.
Selected commercial work by Greenbox Design Studio. Tap any image to enlarge.
Frequently asked questions
What floor loading does a gym need?+
Three to four kN/m² in cardio, four to five in resistance and functional zones, five to seven and a half in free weights, and seven and a half to ten plus impulse under Olympic lifting platforms. On any floor above ground a structural engineer must confirm the actual slab capacity in writing before the layout is fixed.
How much does gym flooring cost?+
₹180–₹380 per sq ft for 8–12 mm rubber tile in a cardio zone, ₹280–₹480 for 12–15 mm under machines, ₹450–₹900 for 20–30 mm with an isolation layer in free weights, and ₹1,200–₹2,400 within a floating Olympic platform. Sprung studio floors run ₹380–₹1,100.
How much ventilation does a gym need?+
Ten to fifteen litres per second per person, against the eight to ten used for an office, because exercising bodies produce three to six times the CO₂ and much more moisture. Cooling is a separate calculation: forty people exercising generate roughly 14–20 kW of sensible heat before the equipment is counted.
What does a gym fit-out cost per square foot?+
₹1,400–₹2,000 for a society or apartment gym, ₹1,600–₹2,400 for a neighbourhood commercial gym, ₹1,700–₹2,600 for a boutique studio, ₹1,500–₹2,300 for a strength box and ₹2,400–₹3,200 for a premium club. All ex-GST and all excluding fitness equipment.
How many showers and lockers does a gym need?+
About 1.2 lockers per peak-hour member and one shower per twenty-five peak-hour members, with individual cubicles that include a dry changing space rather than a communal row. Under-provision here causes more cancellations than any equipment shortcoming.
Should a gym be fully mirrored?+
No. Full-height mirrors on the free-weight wall and in the studios, and nowhere else. A fully mirrored gym is disorienting, doubles the apparent crowd at peak and makes the space feel busier and smaller rather than larger.