The most expensive fit-out mistake isn't overspending, it's building the wrong things in the right space, or renting a bay that can't support your trade no matter what you spend. Both are avoidable with one table. Below is what each major flex-bay user type actually needs, drawn from what each trade requires. Find your row, then walk every tour with it. (For what these items cost, see the per-square-foot guide.)
01The spec table
| Your Work | Power | Floor & height | Air / environment | The must-have people forget |
|---|---|---|---|---|
| Auto & Detailing | 220V for lift and compressor; 100A panel minimum | Lift needs ~4″ reinforced slab & 11'+ under hook; coated floor pays for itself in cleanup | Exhaust extraction if engines run inside; floor drain rules for wash bays vary by town | Ask about the oil/water separator and vehicle count allowed outside, before signing |
| Gym & Fitness | Modest, but plan circuits for HVAC, sound, screens | Rubber flooring over slab ($3 to 6/SF); 16'+ clear for rigs, ropes, wall balls | Ventilation per occupant, not per SF, a full class needs real air turnover | Restrooms/showers gate the occupancy permit; dropped bars are a slab conversation, tell your landlord |
| Welding & Fabrication | The heavy row: 3-phase or big single-phase 220V; know every machine's draw | Bare sealed slab: skip coatings that burn; layout room for material handling | Fume extraction is non-negotiable; separate grinding dust from finishing areas | Fire-rated separation and hot-work rules in the lease; compressed-air runs before racking goes in |
| E-Commerce & Resale | Light: outlets for stations, chargers, label printers | Racking loves 25' clear: vertical cube is free inventory space | Basic heat/dehumidification to protect inventory | A packing station near the roll-up door and a photo corner, the two highest-ROI square feet in the bay |
| Service Contractor | Standard 110/220V for charging and small tools | As-is slab is usually fine, this is Tier 0 territory | Heated storage protects trucks' worth of material | Secure gear cage + camera; your bay is a depot, and depots get visited after hours |
| Studio / Office-Forward | Clean power, dedicated circuits for gear | Polished or coated slab; partition an office box, keep the volume | Mini-splits for the office zone only, conditioning the whole bay is a heating bill, not a plan | Sound: insulation and door seals if you record, teach, or take calls all day |
02Three rules that cut across every trade
Power capacity, clear height, door size, and slab strength come with the building, they're nearly unbuyable afterward. Everything else (walls, coatings, racking, air lines) is yours to add cheaply. So choose the bay for its bones and budget for the add-ons, never the reverse.
Every lease has a use clause and an alterations clause. A landlord who knows flex partners (that's the business we're in) will walk the plan with you, flag the permit items, and often say yes in writing. Springing a lift installation on a landlord after signing is how relationships, and deposits, go sideways.
Open at Tier 1, upgrade at month six from cash flow. The mezzanine, the second lift, the shower, almost everything worth having can wait for the business to pay for it. The only unphaseable items are the ones in rule one.
Ask the Welcome Team for the power, clear height, door size and permitted uses of the exact bay, and our bay types page maps trades to layouts. If you tell us you're building a gym, we'll tell you which of our bays can't take it. That candor costs us the occasional lease and earns us the partners who stay.
“Choose the bay for its bones. Everything else is yours to add.”
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