When you do any structural work and or the following: reroofing, replacement windows, wood/pellet stoves, fireplaces, sheet metal work, demolition, solar panels, insulation decks, additions, some interior alterations, sheds, garages, swimming pools, stairways, fences over 7 feet in height and any new construction. This is not an all-inclusive list so if you are not sure, please call the office at 978-897-1302. A permit may not be necessary if it is considered an ordinary repair