ADU Types / Garage Conversion
Garage Conversion ADU in Maryland
The fastest route from idea to finished unit. The structure, slab, and roof already exist — which takes the two most expensive line items off the table before work even starts.
A garage conversion turns space you already own and already heat the perimeter of into a legitimate dwelling. Because the foundation, walls, and roof are standing, the work is almost entirely interior: making the envelope habitable, getting plumbing and a compliant electrical service in, and finishing it to a standard someone will actually pay rent for.
The honest trade-off is parking and storage. For a household with a driveway and no real need for covered parking, that is a cheap price for a rentable unit. For a two-car household on a street with no on-street parking, it may not be.
What Makes a Garage a Good Candidate
- Slab condition and height. Garage slabs are usually poured lower than the house floor and pitched toward the door for drainage. Both are solvable, but they affect cost, and a cracked or settled slab is a bigger problem than a sloped one.
- Ceiling height. After insulation and a finished ceiling you need to land above minimum habitable height. Low trusses are the most common reason a garage does not pencil.
- Detached versus attached. A detached garage often converts more cleanly, because it is already a separate building with its own entrance and no shared wall or fire-separation questions.
- Electrical service. Most garages carry a lighting circuit and an outlet or two. A dwelling needs a real panel or subpanel, and whether the main service has capacity is a question to answer early.
- Plumbing distance. How far the garage sits from existing drain lines drives the plumbing budget more than fixture choices do.
What the Build Involves
The overhead door comes out and gets framed into a proper wall with windows — done well, this is the single biggest factor in whether the finished unit reads as a home or as a converted garage from the curb. The slab gets leveled or a raised subfloor goes in, with insulation underneath, because an uninsulated slab is the fastest way to a unit nobody wants to live in through a Maryland February.
From there: insulating and air-sealing walls and roof that were never meant to hold conditioned air, running plumbing and electrical, adding heating and cooling, and interior finishes. Egress and fire separation requirements apply, and on an attached garage the separation detail between the unit and the main house matters to the inspector.
Cost and Permitting
Garage conversions in Maryland typically run $90,000 to $150,000, with insulation approach, plumbing distance, and finish level accounting for most of the spread. See the ADU cost guide for the full breakdown.
Converting a garage to a dwelling requires a permit — it is a change of use, not a remodel. Anne Arundel County handles it under Bill 6-23; our Maryland ADU law guide covers what applies.
Garage Conversion Questions
Can I keep part of the garage for storage?
Often yes. Partial conversions that carve a storage or utility bay out of one end are common, particularly in two-car garages. It reduces the finished square footage and therefore the rent, so it is worth deciding deliberately rather than by default.
Will it hurt resale to lose the garage?
It depends on the neighborhood. Where covered parking is scarce and expected, losing it costs you something at sale. Where driveways are long and garages are used as storage anyway, a legal income-producing unit is usually worth considerably more than the bay it replaced.
How long does a garage conversion take?
Construction is typically the shortest of any ADU type, since there is no foundation or exterior shell to build. Design and permitting still take their own time on the front end. We give you a real schedule at the consultation rather than a best case.
Have a Garage You Barely Park In?
We convert garages across Anne Arundel County. Call (410) 755-7663 and we will look at the slab, the ceiling height, and the service panel, and tell you straight whether it works. Weighing options? Compare all five ADU types.