Every concrete project does not necessitate the use of rebar. The usual rule of thumb is that if you are pouring concrete that is more than 5 inches deep, you should generally add some rebar to assist support the entire construction. Concrete is heavy and any holes or voids where it can bulge through will make your floor less stable and may cause it to crack. Rebar comes in various sizes and shapes but usually is about as thick as a drinking straw and is available in 20-foot lengths with square ends or 45-degree cut ends. The most common type is stainless steel, but other materials such as iron and plastic can be used as well. Rebars are added to concrete mixes to provide strength and stability during hardening of the material. They also help to prevent the formation of large air bubbles under the surface of the finished slab. These bubbles can appear on top of the slab as small pockmarks or may even be visible from below if they are large enough. If you plan to install any heating or cooling systems in your garage, then you should allow for space for piping. This means the distance between the floor and ceiling should be at least 1-1/2 feet so that there is room to run pipes without hitting obstacles. You should also ensure that your garage has an electrical panel located near the center of the room so that cables can be run throughout before walls are built.