Updated August 29th, 2017
What is formwork?
If we want to make something to a particular shape than we need a mould. Mould is called form in concrete industry. Procedure of making concrete form is called formwork. Therefore, we can say, Formwork is the making a temporary construction to give fresh concrete a shape and support till it hardens. Concrete form and concrete formwork both words express same meaning.
Types of Formwork
Depending on using purpose, formwork are two types – wall form and slab form.
Wall form: Form, which are used in vertical member, such as column, is called wall form.
Slab form: Form used for horizontal member, is called slab form.
There are some other types of formwork available in construction sector. Such as Traditional form, Permanent form, Tunnel form etc. That will be discussed later here on “ACE”. At this stage of writing this post, one thing came into my mind that I would like to make clear to my readers. Someone categorized formwork depending on materials used for formwork. Such as Timber formwork, Steel formwork etc. But actually that isn’t the types of formwork. That is the “Types of formwork material”.
Works involve in making concrete formwork
Making concrete formwork involves following basic operations –
Propping and centering
Short descriptions of each operation is given below:
Propping and centering: This operation is done depending on types of formwork. If you are making horizontal formwork then it is done first. If you are making vertical formwork then it is done after shuttering. This operation involves giving support to structure and workers for next operation.
Shuttering: shuttering is more often used as similar meaning of formwork. But it is a part of making formwork. This is the main operation of formwork. In this operation side and bottom shutter of RCC members are fixed. For vertical RCC member it is done before propping. And for horizontal RCC member it is done after propping.
Leveling: Its name describe all about it. It is done to give concrete member a desired place and shape.
Cleaning: In this operation cleaning, watering or oiling is done to formwork.
Commonly used formwork materials are timber, steel and plywood etc. See “Types of concrete formwork material“.
Required duration for removing concrete formwork
Vertical side: Vertical side of beam, column, and wall requires 24 hours to open.
Slab formwork: Slab can be removed after 3 days but props should be left under. These left props can be removed after 7 days if the slab span below 15 feet. If slab span above 15 feet, than it requires 14 days.
Beam Soffits: Beam Soffit requires 7 days to remove. But props should be left under. Pros can be removed after 14 days if the beam span below 20 feet. For over 20 feet beam span it requires 21 days.
During the concrete formwork operation, we often use many terms such as stripping, propping etc, as a construction professional, we should be familiar with those terms. I will write about those terms someday here in “ACE”.