• Fire Lanes. Start your layout estimations by taking 25-35% of your floor area and devote it to to-code fire lanes. This is dead space that you cannot use, and must keep clear in order to pass fire and building code inspections. Your percentage will vary based on your architecture.
• Welcoming Area. Front desks, sign-in kiosks, and the like generally take 50-250 square feet, if you need them.
• Social Area. Your members need to gather somewhere to socialize – if you don’t provide them one, they’ll carve out their own space. Think about how many people you want gathered at any one time, and realize that seated people need a minimum of 15-40 square feet per person.
• Dedicated Classroom/Conference Rooms. Spaces all over the world have found that quiet, noise-isolated classroom areas are invaluable if you’re offering educational programs. Consider including one in your floorplan, and consider that you’d probably need 20-50 square feet per seated person.
• Workshops. Do you want to dedicate space to tools? If so, you need to allow for enough space for people to work safely. I’ve found a good minimum size for workshop space of any one craft type is 300-500 square feet, and you need approximately 75-150 square feet per person working independently in a space. Different craft types usually need separate areas (especially woodworking, fabric arts, and welding), so don’t expect to multi-task too much in these spaces. Many groups have had success using the Grizzly Workshop Planner to lay out their space.
• Storage Space. Members need some way to store their projects, especially if they don’t have a studio of their own. Make sure to include some space for shelving (8-12 square feet per shelf unit) if you can. Artisan’s Asylum also offers rental space in the form of areas dedicated to pallet-based storage; one pallet takes up 13 square feet.
• Gallery/Display Area. Do you want to display member work, or advertise your services? Keep in mind how much space that might take up.

Taken from Makezine