Formwork is a necessary component of many construction projects. It molds concrete into the shape of a structure. It also supports the weight of wet concrete until it sets. Construction workers construct the formwork from materials such as plywood, concrete, or fiberglass. Formwork must be strong and rigid to prevent leakage, swelling, or warping. It must also be able to resist the impact of poured concrete and live loads such as vibration, compaction, and evaporation.
When used properly, formwork is an effective and affordable way to make concrete structures such as driveways, walls, or foundations. It is also a cost-effective method for pouring small slabs of concrete for sheds, gardens, or other home improvements. It’s important to use the correct type of formwork for the specific project to ensure that the finished concrete is strong and durable.
Formwork can be made from a variety of materials, but most common is timber, which is cheap and easy to work with. It’s important that timber formwork is well-dried before being used and that it’s positioned and supported adequately to keep it from collapsing under the weight of wet concrete. It’s also possible to use permanent insulated formwork, which is typically constructed of polystyrene foam that stays in place once the concrete has set.
Regardless of the type of formwork used, all must be constructed to meet the requirements specified in the construction plans and to remain stable while concrete is being poured and compacted. It must also be capable of withstanding the stress of a live load and be easily struck (removed) once the concrete has gained sufficient strength.
For large projects, contractors may divide a concrete slab into two parts and pour each half on different days to avoid overworking the concrete. They may also add dividers to a concrete wall or column to create rooms or other openings. This helps reduce the amount of time that the concrete is exposed to the elements, which increases its strength.
While it’s a good idea to plan the layout of formwork carefully, it’s not essential that the exact placement be matched exactly. However, it is a good idea to plan for the sequence in which the formwork will be removed so that it’s not damaged in the process.
For safety reasons, contractors should not attempt to remove or strike a formwork until it has reached the minimum curing time specified in the formwork design and/or until it has received certification from a laboratory following concrete testing. Early removal may damage the concrete and cause premature deterioration of the formwork. It’s also a good idea to monitor the formwork during the concrete pouring and early stages of stripping to identify any potential problems and take measures to prevent them. In addition, it’s a good idea to limit the number of slender pieces of formwork that are used so that the amount of timber or plywood required is minimized. This will help reduce the cost of the formwork and speed up the process.
