How Much Can You Expect To Spend Converting A Garage Into An Apartment?

An average one-car garage usually covers around 240 square feet. The number goes up to 360 square feet if you can comfortably park two cars, with a three-car parking taking up about 704 square feet. Curiously, a small studio apartment ranges between 270 and 320 square feet. So, you might want to take advantage of your garage space and turn it into a rental unit for a little side income or expand your living quarters to accommodate your growing family or coming-of-age children. Alas, outfitting your bare-bones garage with the basics of an apartment, like a bathroom, AC, and windows, will cost you a pretty penny.

To understand the expenditure associated with converting a garage into an apartment, House Digest spoke with Carmine Argano, owner of Creative Design Ceramic Tile & Bath and a general contractor based in Long Island, for an exclusive interview. Drawing from his experience, he details, "From what I see here on Long Island and other parts of New York, a normal single-car garage conversion usually costs around $40,000 to $70,000. A two-car garage can go $70,000 to $120,000, depending [on] how fancy the homeowner wants it." Breaking it down, he recommends setting aside $6,000 to $12,000 for framing, insulation, and subfloor alone. Electrical work will rack up a bill of $3,000 to $8,000, while you should account for about $8,000 to $18,000 for plumbing (if you're adding a bathroom), $4,000 to $10,000 for HVAC or mini-split install, $2,500 to $7,500 for windows or doors, and $6,000 to $15,000 for drywall, flooring, and paint. Permits and inspections can set you back by as much as $800 to $3,000.

Besides the obvious expenses, there are a number of unexpected costs that might arise while you're busy converting your garage into an apartment. Speaking exclusively with House Digest, Argano illustrates, "A big unexpected cost I see arises due to slab issues. Garages often have unlevel concrete or cracks, and fixing that can cost another $2,000 to $6,000." Since you should think twice before using popular floor-leveling solutions, you might have to replace the slab completely. Your garage's size and the job difficulty level will determine the actual price you'll have to pay.

"Another unexpected expense is plumbing. People don't realize how far the main line is or how much concrete has to be cut," cautions Argano. Plus, you'll have to hire licensed professionals for the job, so you might have to spend $1,500 to $4,000 on plumbing. "The same goes for electrical service upgrades in older homes because they can't handle the extra load." As a result, electricity charges will range between $1,000 and $3,000. That's not all. "You might also pay for insulation requirements, fire-rated walls, or zoning rules, depending on your town." To put this into perspective, insulation alone will cost anywhere from $0.4 to $6 every square foot. "And if the homeowner wants to raise the floor to match the rest of the house or finish the ceiling nicely, those can also add a few thousand dollars more." Be prepared to shell out $1,000 to $4,000 for the flooring of your choice. A decorative ceiling or one with a sunroof will further burn a hole in your pockets.

When prompted to share any DIY measures that can save homeowners some money, Argano mentions in his exclusive interview with House Digest, "Honestly, most of the big upgrades should be left to professionals because of permits and inspections." So, don't attempt to bring down expenses by undertaking plumbing work or installing the HVAC yourself (the two priciest projects). Electrical or structural work is another thing you shouldn't attempt on your own. "But there are some safe DIY things. For instance, painting can easily save $2,000 to $4,000." Just ensure you get the must-have tools for a flawless home paint job. Flooring can help you save a few thousand dollars as well. "Simple flooring like click-lock vinyl can save money, too. If the slab is even, you can do it over a weekend." Moreover, you can undertake "basic demolition, like removing old shelves or cleaning out the space."

Shocked by how much you'll have to spend? Well, a garage to apartment conversion could be worth the money and offer a decent ROI (return on investment) if you plan on selling your house in the future. Explaining when and why the transition is worth it, Argano says, "Most of the time, yes. You're taking a space that's just storing junk or a car and turning it into something that actually works for the family." That being said, don't go in blind, or you could run into legal problems later. "But I always tell homeowners this: Check the zoning laws first and make sure it's legal where you live," he recommends.