Standard garages in new house plans often have a garage ceiling height of 9 or 10 feet. Local building authorities will provide dimensions for your locale, which will likely come closer to 8 feet. A higher ceiling allows for better lighting, an overhead garage door system and possible storage. One way to create a spacious garage is to install trusses on block walls built approximately 10 feet high after allowing for the concrete floor depth. A garage floor can be constructed lower than a house floor, too, so the floor-to-ceiling garage space is 9 or 10 feet.
It's possible to build a well-planned garage with a ceiling just 8 feet high or lower. In situations where a large shed is turned into a garage, you may choose to work with existing ceiling height. The limited space might keep you from installing an overhead roll-up door. A hinged garage door, resembling a carriage door that you swing open by hand, might work in this situation. If you store an old vehicle or antique car, the limited height won't necessarily matter, because you won't move the vehicle on a regular basis.
Garage loft space creates unique storage. By adding access steps or a pull-down ladder, you will find lots of usable room overhead. Using the garage attic to store camping gear or Christmas decorations will free up basement space, for example. If you plan to utilize a garage attic for a room or storage, you will need to plan the ceiling height during construction. It's possible, for example, to make a tray ceiling by attaching ceiling joists 1 foot higher on sloping roof rafters.
The housing of an automatic garage door openers typically require 18 inches of clearance overhead, which includes the tracking doors move on. That's why 9 or 10 feet for a garage ceiling makes sense. If you have anything strapped to the top of your car, such as camping gear, you want to pull inside the garage with room left over.
Short garage ceilings may affect quality of air for an attached garage. Any car will emit some fumes when you drive into the garage. By having a 7-foot garage, for example, you risk having more auto exhaust fumes coming into living space through a common door. You don't want carbon monoxide, for example, coming in via a kitchen door opening into the garage. A somewhat higher ceiling helps take care of fumes that will rise and move out of the garage.