Planning Guide: Garage Conversion
The solution to your need for more space may already be attached to your house! Converting an existing garage is less expensive than building an addition—and it's a lot less complicated too!
Remaking your garage into an extra bedroom, den, or kids’ playroom can improve not only the resale value of your home but also your quality of life. In comparison to building an addition, a garage conversion is much more affordable and entails fewer bureaucratic hurdles, but that’s not to say it’s a simple project. As you begin planning yours, take into account these essential considerations.
In a garage with a flat and dry concrete slab, homeowners have no shortage of flooring options. Tile, whether ceramic or vinyl, holds appeal for its ease of installation. It can be laid directly over the slab, so long as the slab is properly prepared. This typically entails filling cracks with patching compound, cleaning spills with a degreasing solution, and applying sealer to block moisture from rising up through the porous concrete.
Less affordable and more demanding to the do-it-yourselfer are carpeting or hardwood. Both materials require a plywood subfloor, which means the project must begin with patching, cleaning, and sealing the slab. After that, lay down a layer of polyethylene sheeting to further safeguard against moisture. Then attach 3/4-inch plywood to the slab with concrete screws at 16-inch intervals. The carpeting or hardwood is then installed over the plywood, resulting in a raised floor height that will need to be managed at the garage entryways.
DOORS & WINDOWS
Many who complete a garage conversion ultimately choose to leave the garage door intact, imbuing the space with a note of industrial flair. Other homeowners replace the garage door with a solid or windowed wall, or with a compromise solution, such as French doors. As you contemplate the design of your garage conversion, ask yourself whether the space has a sufficient number of windows. If you’re planning to add any, consider not only natural light and views to the outdoors, but also privacy.
WALLS & INSULATION
You’re ahead of the game if your garage walls are insulated and paneled in drywall. If they aren’t, however, how you address the issue often depends on how your garage is constructed. If the exterior walls are cinderblock, then outfit the perimeter of the space in stud framing. Fit insulation between the studs and then fasten the drywall to the framing. (For walls with drywall but no insulation, spray-foam insulation can be used with little disruption to the status quo.) Before closing up the walls, remember to run electrical wire for overhead lighting. Also at this stage, you must frame out any closets you wish to include as part of your garage conversion.
Once the walls are in, hire a licensed electrician to install outlets and light switches, as well as any fixtures you wish to mount on, or hang from, the ceiling. (Note that it may be necessary to add a circuit to your breaker panel.) Of the many reasons to hire a professional to handle the electrical work in your garage conversion, perhaps most important is the pro’s in-depth knowledge of the relevant building codes in your area.
HEATING & COOLING
If you have a forced-air system, the simplest (read: most cost-effective) method of heating and cooling your garage conversion is to extend the ductwork from the main part of your house. Alternatively, look into radiant floor heating, which operates through the floor by means of heated water or electrical coils. Yet another option is to install a mini-split heater and/or air conditioner. Known as a ductless system, this technology consists of a wall-mounted unit that draws from a condenser situated immediately outside the building. As a final set of options, consider the traditional amenities for small-space seasonal comfort, namely baseboard heaters and window air conditioners.
Installing a kitchen, bathroom, wet bar, or utility sink can be the most complicated part of a garage conversion. Chances are good that in order to have running water, supply and drain lines will need to be set into the concrete slab. For that reason, it’s wise to handle plumbing issues first, before addressing other features of the project. If you wish to build a bathroom but are leery of disrupting the slab, think about an up-flush system, which relies on a macerator (to grind waste) and a pump (to take that waste to your septic tank or sewer). In this setup, supply and return lines are boxed out along the floor, but they almost disappear from view once you have painted and furnished the renovated garage space.