In my 20 years as a professional home inspector, I’ve seen my share of garages converted to living spaces. I’ve also seen many a botched garage conversion.
It’s not my favorite way to create more living space, since converting it can cost nearly as much as an addition. But if you’re thinking of going this route, go all the way. Don’t keep the telltale garage giveaways like the large door that no longer opens because you’ve installed a wall behind it, or a driveway that leads right up to the exterior wall. If you want to protect your home’s resale value, make this renovation look like a garage was never even a part of the house plan to begin with.
There are plenty of other garage design peculiarities that also must be dealt with. For example, most garage floors are sloped. To level yours out, you may need to build a wood floor on “sleepers” ─ beams that sit on the floor and are cut at a reverse angle to give the appearance that the floor is flat. You’ll probably also need to build up a section of the exterior wall with concrete block where you took out the overhead door in order to match the rest of the foundation.
Perhaps the trickiest part of a garage conversion is adding heating and cooling to the formerly unconditioned space. Be sure to check with an HVAC pro to determine the best way to do this for your particular project. It’s important to ensure that your existing heating system has both the capacity to heat more space and that your building has the room to add the needed ductwork or hot water heating pipes.
Lastly, remember that garages are generally only insulated on the wall that connects them to your home (a.k.a. the firewall). You’ll need to add insulation to the remaining walls, and if they’re already covered with wallboard, consider having some insulation blown in.
Bottom line: Although it’s not ideal, a garage conversion can be an option if you have a new addition to the family, want extra income by renting out the room, or have a lifestyle change that requires making space wherever you can get it. Just make sure to erase all evidence that your new living space was once a garage, and you’ll have a project that won’t hurt your home’s resale value.