Formwork is a term used for the process of creating a temporary mould into which concrete is poured and formed. Traditional formwork is fabricated using timber, but it can also be constructed from steel, glass fibre reinforced plastics and other diverse materials.
While formwork is a broad term that is used concerning the forming process using a wide variety of materials, shuttering is a term that is often used to refer to the process of using plywood to form the mold.
Shuttering is perhaps the most popular type of formwork and is normally constructed on-site using timber and plywood. A special grade of plywood is necessary for shuttering, and it must be water-resistant. It is easy to produce, although it can be time-consuming for larger structures. It is used when the labor costs are lower than the cost of producing re-usable formwork from materials such as steel or plastic. It also has the advantage of being at a significant amount of concrete that can be poured at once.
Simple plank formwork can be used for the construction of a road or hard floor. Planks should be trimmed to be flush with the top surface of the slab, allowing for a neat concrete finish.
The requirements to consider to qualify for a good formwork job are:
- Strong enough to withstand dead and live loads.
- Capable of retaining its shape by being efficiently propped and braced horizontally and vertically.
- Joints should prevent leakage of cement grout.
- Should be capable of being removed in various parts without damaging the concrete.
- The material used be suitable for reuse.
- Should be set accurately to the desired line.
- As lightweight as possible.
- The material should not warp or distort on exposure to the elements.
- Should rest on a firm base.
In the next article, we will know the types of formwork that exist.