The process of shuttering involves setting up temporary structures that will act as molds for concrete as it sets. Shuttering material may include panels, precast molds, and various fastening and support devices known as falsework. The key shuttering material is the panel, which can be made from steel, aluminum, plastic, or even certain types of plywood that feature a protective coating that will prevent moisture damage. The panels are what give the concrete its shape as it sets, and various types of panels exist. Falsework can include rods, pins, couplers, or even just simple boards acting as supports.
Plywood panels are perhaps the most common because they are inexpensive, relatively lightweight, and easy to store and transport. They can be susceptible to damage fairly easily, especially warping, though the plywood used as shuttering material will generally be treated to prevent such damage. A protective film or veneer is usually applied to the broad face of the plywood to prevent the concrete from adhering to it. When plywood is not feasible to use, steel panels can be substituted. These tend to be exceptionally durable and will not yield under heavy loads, but the panels can be quite heavy and difficult to put in place. As a shuttering material, steel is also generally more expensive.
Precast plastic molds are also available for certain projects, and in some cases, the plastic shuttering material may become a permanent fixture rather than a temporary mold. The strength of the plastic will generally depend on its thickness, and some thicker plastics are suitable for fairly large projects. Plastic molds can also be reusable because they are easy to clean, lift, and store in most cases. Another type of shuttering material that can become a permanent fixture is aluminum; corrugated aluminum is sometimes used for concrete projects, and once the concrete sets, the aluminum may be left in place. Aluminum is generally resistant to corrosion, making it suitable for long-term exposure to moisture.
Falsework must be used to secure the panels in place. Metal rods, rebar, couplers, wood beams, and clamps are often used to secure panels in place, and these components must be easy to use because they will usually be removed after the concrete sets. Some types of falsework are even adjustable to accommodate different needs; steel supports, for example, may feature a screw device that allows the support to be height adjustable.