Insulated concrete form (ICF) is a system of formwork for reinforced concrete usually made with a rigid thermal insulation that stays in place as a permanent interior and exterior substrate for walls, floors, and roofs. The forms are interlocking modular units that are dry-stacked (without mortar) and filled with concrete. The units lock together somewhat like Lego bricks and create a form for the structural walls or floors of a building. ICF construction has become commonplace for both low-rise commercial and residential buildings as more stringent energy efficiency and natural disaster resistant. Traditional finishes are applied to interior and exterior faces, so the buildings look similar to typical construction. ICF construction requires simple slabs shallow foundations, less labor force and minimal handling and lifting equipment.