Garage conversion rules in Gaithersburg, MD β sometimes called garage-to-ADU or accessory living unit conversions β govern permits, ceiling height, egress, and parking replacement.
Converting a garage to living space in Gaithersburg requires a building permit and zoning review. The conversion must meet residential building code standards for habitable space including egress, insulation, ventilation, and ceiling height. Off-street parking requirements must still be satisfied after the conversion. Garage-to-ADU conversions follow the city's accessory dwelling unit regulations.
Gaithersburg allows garage conversions to living space with proper permits and zoning compliance. A building permit is required from the Building Division at (301) 258-6330. The converted space must meet International Residential Code standards for habitable rooms, including minimum ceiling height of 7 feet, natural light and ventilation (window area at least 8 percent of floor area), adequate insulation to meet current energy code, and egress windows in sleeping rooms. The existing garage slab may need moisture barrier improvements. Electrical, plumbing, and HVAC work each require separate trade permits. The conversion must not reduce the property's required off-street parking spaces below the minimum for the zoning district. In most single-family zones, two off-street parking spaces are required. If converting a two-car garage, alternative parking solutions such as driveway expansion may be needed. Converting a garage to an accessory dwelling unit follows Gaithersburg's ADU regulations including owner-occupancy and size limits. The exterior appearance after conversion must be compatible with the neighborhood character. Contact the Department of Planning and Code Administration for a pre-application meeting to discuss feasibility.
Converting a garage without permits is a building code violation. Habitable space that fails to meet egress, ventilation, or ceiling height standards is a life-safety violation subject to immediate correction orders. Loss of required parking spaces without zoning approval is a separate violation.
Gaithersburg, MD
Montgomery County Bill 35-20 bans gas-powered leaf blowers countywide effective January 1, 2025, which applies within Gaithersburg. Only battery-electric and...
Gaithersburg, MD
Gaithersburg enforces noise regulations under City Code Chapter 15 and Montgomery County Code Chapter 31B. Noise that is plainly audible beyond property boun...
Gaithersburg, MD
Gaithersburg addresses barking dog complaints through City Code Chapter 15 noise provisions and Montgomery County animal control regulations. Dogs that bark ...
Gaithersburg, MD
Montgomery County Code Chapter 31B sets specific decibel limits for Gaithersburg based on zoning and time of day. Residential zones are limited to 65 dBA day...
Gaithersburg, MD
Gaithersburg requires EV charging pre-wiring in new residential construction. Maryland law effective October 2022 prohibits non-EVs from parking in designate...
Gaithersburg, MD
Gaithersburg regulates street parking through Chapter 14 of the city code and a Residential Permit Parking program updated in 2025. Parking restrictions vary...
Side-by-side rule comparisons with other cities in Montgomery County.
See how other cities in Montgomery County handle garage conversions.
See how Gaithersburg's garage conversions rules stack up against other locations.
Quick Compare
Help us keep this page accurate. If you notice an error or outdated information, let us know.