What is Formwork in Construction?
What is Formwork in Construction?
Formwork refers to temporary or permanent molds or structures used to hold and shape wet concrete or similar materials as it cures. In concrete construction, formwork is used to create the shape and form of the structure. It can be precast, meaning it is made offsite and brought to the construction site, or cast-in-place, meaning it is built on site.
Falsework is a type of formwork that supports the formwork itself during the construction process. Formwork can also be incorporated into the final structure, serving as insulation or reinforcement.
Types of Formwork
There are several types of formwork used in construction:
Traditional Timber Formwork:
This is made on site from wood and plywood or particleboard and is used to create the shape and form of the structure. It is flexible and can be used for complicated sections, but it is time-consuming for larger structures and the plywood facing has a limited lifespan.
Engineered Formwork System:
This is made from prefabricated modules with a metal frame (usually steel or aluminum) and covered on the concrete side with a material that has the desired surface finish (steel, aluminum, wood, etc.). It is faster to install than traditional timber formwork and has lower life-cycle costs because the metal frame is more durable.
Reusable Plastic Formwork:
These interlocking and modular systems are used to build simple concrete structures and are lightweight and robust. They are suitable for mass housing projects and similar structures and can be mounted on existing roofs or constructed without a floor and lifted onto existing structures using a crane.
Permanent Insulated Formwork:
This formwork is assembled on site, usually using insulating concrete forms (ICF). It stays in place after the concrete has cured and may provide advantages in terms of speed, strength, thermal and acoustic insulation, and space to run utilities within the expanded polystyrene layer.
Stay-In-Place Structural Formwork Systems:
This formwork is made from prefabricated fiber-reinforced plastic forms that are assembled on site and used for columns and piers. It stays in place after the concrete has cured and serves as reinforcement and confinement for the concrete.
Flexible Formwork:
This system uses lightweight, high-strength sheets of fabric to take advantage of the fluidity of concrete and create optimally designed, architecturally interesting building forms. It allows for the creation of structures that use significantly less concrete than equivalent strength prismatic sections, which can result in significant embodied energy savings.
