Formwork is used to shape and support concrete until it gains strength. It can be made from various materials like timber, plywood, steel, aluminum, and plastics. Timber was traditionally most common but other materials are increasingly used. Different types of formwork exist for walls, slabs, columns, etc. Proper formwork construction involves propping, shuttering, providing chambers, cleaning, and surface treatment. Formwork must be removed carefully in the proper sequence once the concrete has gained enough strength. The type of material used depends on factors like cost, availability, and need for reuse.