Garage space is easy to convert to a bedroom provided the floor is sound. Since walls and a floor already exist, it's cost-effective to build a bedroom in this space. Most garages already have a breaker box and electric outlets in the space, so this saves time and money. A garage is a good place to build a bedroom for a teenager or elderly parent who desires privacy. You can always build a carport to replace the storage area for your car.
Measure the space you can allocate for a bedroom area. Even if you use all of the parking space you used for cars, you can still leave a storage space on one side of the area. If your garage is a one-car space, consider expanding the room beyond the garage door. By adding a bump-out on your house, you can create a bedroom that provides plenty of light and space.
Take down the garage door, and check out the ceiling area. You will need to run wiring to light fixtures and wall outlets in your new bedroom along walls and over ceiling joists. Examine the surrounding walls to figure out the most practical way to bring water into the bedroom for a small vanity or bathroom area. If your garage is near the kitchen, you might be able to pipe water straight through an adjoining wall.
Frame the walls, and enclose the opening where the garage door was. Place plenty of insulation on outside walls. Drywall the overhead ceiling area. Place extra insulation in the space between ceiling beams. Create space for an extra exterior window if needed.
Drywall the bedroom space. Hook up light fixtures and place outlet covers. Sweep out the area to prepare for installing flooring. Inexpensive vinyl will work, but this type of floor will be cool in winter. It's better to lay wooden flooring if you can afford it. Tile works well, but it doesn't retain heat as well as wood flooring.
Make the bedroom area special by installing track lighting along one wall to feature artwork or shelves of books. Install crown moulding around the perimeter of the ceiling to give the room makeover a high-end look. Build a wall unit for books or media materials while the room is under construction. It doesn't cost that much to add these types of features when a room is being built. Save on labour costs by building wall storage and bookshelves yourself.
If you install an exterior door to the outside of the home, install a security light and motion detector outside the door. If the door opens to the street side of your home, you want to build in security features.