The most widely used man-made material in the world, concrete is a combination of cement, sand, gravel, water and other additives. Concrete can be used by block or pour. When pouring concrete to create steps or any molded construction, concrete formwork are used. These forms can be made of different materials depending on the kind of job.
Lumber or plywood are excellent choices for building forms. The wood is cut to proper dimensions for the construction and then braced and set on the surface. The inside the form is coated with oil or another release agent that allows easy removal when the concrete has dried.
Using the Form
In order to lower the amount of poured concrete, the bottom of the form is filled with gravel, broken brick or chunks of concrete. Concrete mix is poured over this rubble and into the corners and crevices of the form. They are overfilled slightly so that compression will work out the gaps and air pockets. Using the appropriate tools, screeding and troweling will smooth out the surfaces and prepare the concrete for curing.
Concrete is left in the form for at least 24 hours, but often much longer, sometimes as long as a month or so. The longer the concrete cures in the concrete form, the stronger it is. When the concrete is properly set, the form can be carefully removed.