Expanded metal is a type of sheet metal which has been cut and stretched to form a regular pattern ofmetal mesh-like material. It is commonly used for fences and grates, and as metallic lath to supportplaster or stucco.
Expanded metal is stronger than an equivalent weight of wire mesh such as chicken wire, because the material is flattened, allowing the metal to stay in one piece. The other benefit to expanded metal is that the metal is never completely cut and reconnected, allowing the material to retain its strength.
Some commonly used shapes are circles, squares, and diamonds; diamonds are the most popular shapes because of how well the shape absorbs energy and resists mechanical deformation after installation. Other design considerations are the size and angles of the shapes, which will also affect how well the metal absorbs energy and where the energy is spread throughout the expanded metal