As construction projects are carried out, contractors and engineers usually focus on the materials and design. However, there is an aspect that is often ignored by many–the concrete formwork. This is unfortunate because formwork is one of the more costly parts of construction projects. Robert H. Lab, Jr. wrote an article for Structure magazine that discusses how important formwork is and how much it affects the construction budget:
"Concrete formwork cost is significant. The cost of formwork amounts to anywhere from 40 to 60% of the cost of a concrete structure. […], the cost of concrete formwork and labor can exceed the combined total cost of concrete and reinforcement materials and labor. Formwork materials are only a small percentage of the total concrete formwork costs. The major cost is the formwork labor - the costs associated with the installation and removal of the formwork. Therefore, any effort to reduce the costs of a concrete structure must include the construction process. The concrete structural design engineer must be aware of the cost of construction and design the structure accordingly. A well designed structure utilizes optimum concrete formwork, which obtains fast paced construction while keeping costs at a minimum. A structure that is easy to build reduces the required labor and leads to potential cost savings."
Depending on a contractor’s needs, formwork can come in a variety of materials and forms. First, there is the wooden formwork that is made of timber or plywood, which is easy to build, but not exactly durable. Therefore, it’s only used for smaller structures. Second, there are engineered formworks. Using premade modules made of metal, they are easily applied and can be reused multiple times. The durable aluminum concrete forms for sale by companies like LECO Concrete Forms & Supply are good examples of this.
Third on the list are plastic formworks. Not as rugged as metal ones, they are popularly used when building mass housing, because they can be conveniently interlocked with one another to form simple structures. Fourth, there are permanent formworks that aren’t removed after the concrete has dried. This particular type of formwork helps improve a structure’s strength, energy efficiency, and sound absorption among other benefits.
(Source: Think Formwork - Reduce Costs, Structure Mag)