When concrete is fresh and in its liquid state it must be restrained within a mold in order for it to set in its required shape. Formwork is the term used to describe this mold.

For most in-site pours, the formwork is made of wood. A smooth outer surface provides the main support for the concrete as it sets. This is normally made of plywood.

Concrete is approximately 2.4 times as dense as water, and in its liquid state, it imposes considerable forces on the formwork containing it. Consequently, it is necessary to reinforce the plywood with horizontal wooden beams or wailings.

If constructed properly, this mechanism of a plywood skin supported by timber wailings provides ample support for the setting concrete. The mechanism of transferring these loads to a solid support can be performed by numerous methods which are collectively known as scaffolding.

Formwork is made from expensive materials and requires great skill and experience in its manufactures. Its importance is evident when you consider that the cost of fabrication, erecting and striking the formwork, often exceeds the cost of the concrete it is designed to shape and support.

Formwork usually needs to be used many times for it to be cost-efficient. This can only be done if it is carefully handled, cleaned and stored, regardless of what material it is made from.