Ferrocement or ferro-cement is a system of construction using reinforced mortar or plaster (lime or cement, sand, and water) applied over an "armature" of metal mesh, woven, expanded metal, or metal-fibers, and closely spaced thin steel rods such as rebar. The metal commonly used is iron or some type of steel, and the mesh is made with wire with a diameter between 0.5 mm and 1 mm. The cement is typically a very rich mix of sand and cement in a 3:1 ratio; when used for making boards, no gravel is used, so that the material is not concrete. Ferrocement is used to construct relatively thin, hard, strong surfaces and structures in many shapes such as hulls for boats, shell roofs, and water tanks. Ferrocement originated in the 1840s in France and the Netherlands and is the precursor to reinforced concrete. It has a wide range of other uses, including sculpture and prefabricated building components. The term "ferrocement" has been applied by extension to other composite materials, including some containing no cement and no ferrous material. The "Mulberry harbours" used in the D-Day landings were made of ferrocement, and their remains may still be seen at resorts like Arromanches. Definitions Cement and concrete are used interchangeably but there are technical distinctions and the meaning of cement has changed since the mid-nineteenth century when ferrocement originated. Ferro- means iron although metal commonly used in ferro-cement is the iron alloy steel. Cement in the nineteenth century and earlier meant mortar or broken stone or tile mixed with lime and water to form a strong mortar. Today cement usually means Portland cement , Mortar is a paste of a binder (usually Portland cement), sand and water; and concrete is a fluid mixture of Portland cement, sand, water and crushed stone aggregate which is poured into formwork (shuttering). Ferro-concrete is the original name of reinforced concrete (armored concrete) known at least since the 1890s and in 1903 it was well described in London's Society of Engineer's Journal but is now widely confused with ferrocement. History The inventors of ferrocement are Frenchmen Joseph Monier who dubbed it "ciment armé" (armored cement) and Joseph-Louis Lambot who constructed a boat with the system in 1848. Lambot exhibited the vessel at the Exposition Universelle in 1855 and his name for the material "ferciment" stuck. Lambot patented his boat in 1855 but the patent was granted in Belgium and