A permit is required to construct, enlarge, alter, repair, move, demolish or change the occupancy of a residential or commercial structure. Permits are also required to construct, install, enlarge, alter, repair, remove, convert or replace any electrical, gas, mechanical or plumbing systems. Typical projects that require permits are replacing a furnace and/or A/C unit, replacing a water heater, replacing a deck, or building a fence. Cosmetic interior remodeling, such as replacement of cabinets, doors, carpeting and plumbing fixtures do not require a permit. Siding and window replacement does not require a permit but all roof replacements do.