Often less than a house, but rarely none. That's the honest answer for an office, a studio, a home gym or a sauna, and it's why the first call should be to your city, not your contractor.
The size limit
Many cities exempt small detached buildings from a building permit when they're under a size limit. That limit is commonly somewhere around 120 to 200 square feet, and it varies a lot. Ask your city for its number before you pick a design, because a few square feet can be the difference.
What usually still needs a permit
- Electrical work. Almost always, even when the building itself doesn't. Lights, outlets and a heater all count.
- Plumbing. A sink, a shower or a cold plunge needs water and a drain, and that needs a permit.
- Zoning. Setbacks from your property lines still apply to a building that skips the building permit.
What changes the rules entirely
Adding a bathroom or a place to sleep. A small space with a shower, a toilet or a bed may be treated as a dwelling, and dwellings bring backyard-home rules, more permits and new fees. If you want a bathroom in your studio, check with your city before you draw one in.
Plan for how you'll use it
- An office or studio needs dedicated circuits, conduit for internet, insulation for sound, and windows placed for light on your desk rather than glare on your screen.
- A home gym needs ceiling height for overhead lifts, a solid slab, ventilation, and backing in the walls for racks and mirrors.
- A sauna usually needs its own 240-volt circuit, a vapor barrier, a fresh-air vent and a floor that can drain. Check that your panel has room before you fall for a heater.
Questions to bring to your city
- Is this building allowed on my lot, and what are the setbacks and the height limit?
- Is there a size under which no building permit is needed?
- Which permits will the electrical and plumbing need?
- Does a bathroom or sleeping space change how you classify it?
Have a look at our spaces for studios, offices and saunas, and design yours in the designer to see its footprint on your own lot.