Do I need a permit for basement finishing in Dayton?

Most likely yes. Basement finishing usually requires a permit in Ohio. Confirm the specifics with Dayton.

Under Section 310.6 of the Residential Code of Ohio an escape opening is not required when an existing basement is altered, but every new sleeping room created in a basement needs an emergency escape and rescue opening. Where alterations needing approval reach sleeping areas or add a sleeping room, Section 314.2.2 requires smoke alarms in those areas, and Section 315.2.2 requires carbon monoxide alarms in homes with fuel-fired appliances or an attached garage. New wiring, plumbing, or ductwork needs approval under Section 105.1, and new building envelope work must meet the energy chapter (Section 1109). Ohio's residential code is enforced only by residential building departments certified by the Board of Building Standards, at the city, township, or county level. Confirm which department covers your address. Where none is certified, the owner must still build to the RCO. 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.