Do I need a permit for basement finishing in Franklin?

Most likely yes. Basement finishing usually requires a permit in Wisconsin. Confirm the specifics with Franklin.

In a home built on or after June 1, 1980, a basement used for sleeping needs at least 2 exits, and the second may be an egress window in each bedroom (SPS 321.03(5)(b)); an egress window needs a net clear opening of at least 20 by 24 inches with its lowest point no more than 60 inches above the floor (SPS 321.03(6)). SPS 322.32(6)(a) requires the walls of a conditioned basement to be insulated from the top of the wall down to the basement floor. Wis. Stat. 101.645(3) requires a smoke detector in the basement and on each floor level of a dwelling, and Wis. Stat. 101.647(3) requires a carbon monoxide detector in the basement and on each floor level (except the attic, garage or storage area) of any dwelling with an attached garage, a fireplace or a fuel-burning appliance. Wisconsin sets no statewide permit requirement for additions or alterations to existing homes; under SPS 320.09(2)(b) those permits are required where the local ordinance requires them, and in a municipality where DSPS has UDC jurisdiction building permits for additions and alterations are not required, though zoning and electrical permits may still apply. This basement project adds a bedroom, a bathroom or wet bar, or new electrical circuits, or moves the furnace or water heater. Finishing work of this kind normally needs a building permit and the matching trade permits. A basement bedroom needs an emergency escape and rescue opening, such as an egress window or door, which is one of the most common reasons basement work fails inspection. Plan for framing, electrical and plumbing rough-in inspections before insulation and drywall go up.