If you decide to expand your garage to make more room for tools or storage, this is considered adding on to your home, and costs will typically go up. Home addition costs fall between $20,000 and $70,000 for most homeowners, depending on the size and type of space built. Your contractor will frame out new walls and expand the room's foundation. If you intend to keep the space the same only reorganizing it, you may have only the costs associated with purchasing and installing shelving and cabinetry.
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.
Paint manufacturers have recognized these problems and have come to the rescue with new solutions. But a word of advice: If your garage floor sees heavy water leakage, if it's badly cracked or if it's damp and slimy all summer, don't apply any coating. In those cases, you're better off simply keeping it as clean as you can and then calling it quits.