I agree with the others. It depends on your budget and the type of equipment and amenities you want to put in. You can go around and visit other small studios (or larger gyms) to get an idea of what to buy and as far as layouts. Of course an extensive online search could be as productive. Good luck!
All great answers. When we built our personal training studio in LA we first looked at our current clientele and then to whom we could market, at that time, a newer innovation in fitness training. Flooring is certainly important, but I think that the quality and appropriateness of your training equipment is equally important. Does it match your expected clientele? You’ve some homework to do. Good luck!
That is a big cardio space for a private gym. How big is the rest of your facility? Do you have enough members to justify a cardio space that big? The space itself shouldn’t be that costly if it is already part of your facility. Flooring, lighting, air flow, electrical, and video would be your biggest costs. And all of those depend on what you want from each.