Two types of reinforcement for concrete construction are readily available. One is deformed reinforcing bars, commonly known as rebars. The other is welded wire fabric, also known as wire mesh.
FOOTINGS AND WALLS
Many footings will contain no reinforcement. However, the designer or the local code may specify the necessary amount of steel if it is required by unusual loads, unstable or highly variable soils, or trenches that the footings must span. Reinforcing steel can be used to assure that separate concrete components don't pull apart at the joints. When concrete porches, steps, chimney supports or other concrete elements are to be poured after the concrete foundation walls are in place, rebars and a support ledge or corbel should be provided at the connecting joint. Lintels over wall openings should be reinforced.
SLABS ON GROUND
Reinforcement is not necessary for most slabs on ground when joints are spaced properly to prevent uncontrolled cracking caused by drying shrinkage or large temperature changes.
Concrete slabs on ground are classified in four types, A, B, C, and D. The classification is based mainly on where the slabs are to be used, and the various types differ in their design and use of reinforcing steel. Slab Type A, by far the most commonly used type, is unreinforced. All other slab types are reinforced.
REINFORCEMENT FOR EMBEDDED ITEMS, SLAB DEPRESSIONS AND OPENINGS
Special precautions must be taken for heating coils, pipes or conduits embedded in the slab. They should never be embedded in a slab that is not reinforced because they may cause excessive stresses in the concrete.