Do I need a permit for garage conversion in Middletown Township?

Most likely yes. Garage conversion usually requires a permit in Pennsylvania. Confirm the specifics with Middletown Township.

Changing the occupancy of a residential building requires a permit under 34 Pa. Code Section 403.62(a), and new wiring, heating, or plumbing for the room needs permits under the same section. A detached private garage under 1,000 square feet is outside the UCC under Section 403.1(b)(3) only while it is a garage accessory to a detached one-family dwelling. Converting it to living space is a different use, so confirm the permit path with your code official. For one- and two-family dwellings undergoing alterations, Pennsylvania's version of the 2021 IRC in Section 403.21 does not require interconnected smoke alarms, but noninterconnected battery-operated smoke alarms must be installed. Turning a garage into a bedroom, living room, office or apartment changes it to habitable space, which must meet the code for living areas, such as insulation, heating, ceiling height, light, and an emergency escape opening in any sleeping room. A conversion normally needs a building permit, and often electrical, mechanical and plumbing permits too. Zoning may also require you to keep off-street parking or limit a second unit, so check zoning before you design.