Construction contractors turn to concrete for a variety of projects because they appreciate the material’s outstanding properties. Nevertheless, when using concrete, they must have a mold, known as formwork, to pour the material into. This mold comes in both temporary and permanent versions and holds the concrete in the correct shape until it hardens and can support itself.
Contractors classify Concrete Form Systems by the material used and element supported. Furthermore, the classification system looks at whether the formwork is permanent or temporary. The key lies in finding formwork that can bear the loads seen when casting the concrete and hold the concrete in the desired shape until it properly hardens.
Good Formwork Requirements
When analyzing formwork materials, contractors must consider certain requirements.
- The formwork must withstand dead and live loads.
- It must retain its shape, although braces and props can be used to accomplish this.
- All joints need to be leakproof.
- Any temporary formwork cannot harm the concrete during its removal.
- The material must be reusable.
- The material must be lightweight.
- The material cannot distort or warp.
Contractors must take into account the concrete being used as well as its pouring temperature. Both factors play a role in the pressure exerted on the formwork. Furthermore, choosing a formwork material involves ensuring the form can withstand the weight of both wet and dry concrete.
The contractor must use poles, stabilizers, and other structures to ensure the formwork doesn’t move as the construction progresses. Industry insiders refer to this as falsework. In addition, adequate supervision is needed along with qualified workers to ensure the highest quality.
Timber
Timber serves as a common formwork material and was among the first materials to be used for this purpose. The construction crew assembles the formwork on-site, and it remains flexible. Contractors find it is easy to make, install, and remove. They appreciate its light weight and that it can be formed to any size, shape, and height. Timber remains an economical choice, and locally-sourced lumber may be used.
Nevertheless, only termite-free timber should be used for formwork. This material is only appropriate for short-term projects due to its limited lifespan, and the process is time consuming. As a result, it’s rarely used in large projects. Choose timber for low labor cost projects or when a complex concrete section calls for flexibility in the formwork.
Plywood
Many contractors use plywood in conjunction with timber. It comes in various thicknesses and sizes and is used for decking, form linings, and sheathing. It’s strong, durable, and lightweight.
Metal
Many companies turn to steel or aluminum for formwork. They love the long service life and reusability of steel. However, they may opt for aluminum because it is lighter, although it offers many of the same benefits. However, aluminum isn’t as strong.
Metal provides a smooth finish on the surface once the concrete dries, and it is waterproof. The honeycombing effect is rarely a concern, and crews can install and dismantle the formwork easily. Furthermore, it is very helpful with structures that are curved.
Plastic
Plastic formwork comes in modular systems or interlocking panels. Small projects with repetitive tasks benefit from this type of formwork and cleaning the form requires nothing more than water. The panels and systems weigh very little, but plastic doesn’t offer the flexibility seen with timber.
Fabric
Fabric or flexible formwork consists of high-strength fabric sheets that don’t weigh much. The sheets create unique architectural forms and require less concrete. As a result, the contractor saves money. Furthermore, it allows them to construct complex and irregular shapes.
Stay-In-Place
Certain projects call for formwork that remains in place once the project is complete. The form provides axial and shear reinforcement. Crews construct the formwork on the job site, using plastic forms that are prefabricated and reinforced with fiber. Most commonly seen in columns and piers, the form offers resistance against environmental damage.
Coffers serve as another form of stay-in-place formwork, and they are found in numerous building types. Two filtering grids make up the coffer and are then reinforced with stiffeners. The crew uses articulated connectors to link the coffers, which are easily moved from the factory to the job site.
Permanent Insulated
This type of formwork serves as one of the most advanced and provides permanent insulation. Users love its energy efficiency and sustainability and may choose formwork that resists rodents and fire or that with thermal or acoustic properties, depending on the project being completed. Insulating concrete forms remain the most common, as they insulate the concrete with the help of polystyrene boards.
The type of formwork used depends on the project being completed. What works for one application won’t be appropriate for another. Work with the contractor to ensure the right formwork is selected for the project.
Speak Your Mind