Most rough-framed garages aren’t ready for drywall. Your garage may be missing studs at the corners and attachment points for the ceiling drywall. To see where framing members may be missing, inspect inside corners where walls meet and where the walls meet the ceiling. These are the most common areas needing additional framing. These two photos show how to add ceiling blocking.
A garage remodel is usually much cheaper than a home renovation because the foundation, roof, and walls are already built. Many garages also have electrical and plumbing installed to some extent. The actual cost of a garage remodeling project, however, depends on what the renovated space will be used for. While a new home gym won't require much in the way of amenities, converting a garage to an office, apartment, or bedroom requires adding significantly more creature comforts.
The cost of installing five windows falls somewhere around $5,000, or about $1,000 per window. If your garage doesn't have any windows, plan to add at least one. This is especially important if you want to list it as a bedroom or rent it out. You'll need an egress window big enough for a person to escape through in case of a fire. Egress windows average about $3,500.
Start by insulating the walls. Buy unfaced R-13 batts for 2×4 walls and unfaced R-19 batts for 2×6 walls. Match the width of the batt (15-1/4 in. or 23-1/4 in.) to the stud space. Cut batts carefully for a tight fit. Next, staple 4-mil poly to the walls and ceiling. Embed the poly sheeting in caulk around the perimeter of each piece to create an airtight seal. Seal the seams between sheets and seal the poly to electrical boxes with caulk or special sheathing tape (it’s typically red and looks like packing tape).
Heating & AC ($1000-$5000): Adding central heat and air into your garage can either be simple or difficult. If you have a robust heating and air conditioning system in place it is as simple as expanding your existing ducting. If the additional square footage is more than your system can handle you will need to add in a new unit. Luckily, a small garage usually is able to be fit into your existing system.
But about those new formulations, one is Epoxy Shield garage floor paint. It's a waterborne coating consisting of epoxy and acrylic resins with color chips that you sprinkle over while the coating is wet. Its manufacturer says it’s specifically formulated to withstand hot-tire pickup, moisture vapor and attack by solvents and chemicals that drip from a car or come in on the car's tires. It comes as a kit that consists of a cleaner-degreaser, two paint components that you mix together and nonskid color chips. To apply, first clean and degrease the floor. Then mix the two-part coating together and roll it on. Finish up by broadcasting the nonskid chips onto the coating while it’s still wet. You should be able to walk on the surface in four hours and drive on it after seven days when it’s fully cured. The kit costs about $60.
Update Fixtures: If you have either old, or the most basic fixtures spend a little money and upgrade them. Utility lighting doesn’t have to be bare bulbs with an economy base. Use fixtures that fit into your garage design. Sometimes it has exterior lights, or interior lighting fixtures that just look completely out of place. Make sure you change out these fixtures to ones that fit the area.