Types of Formwork l Best Types of Formwork Materials

What is the Best Type of Formwork?

The curves, columns and arches of architectural visions would not come to fruition if not for the techniques of formwork. In precast moulds, rounded, square or rectangular, formwork allows for the quick construction of concrete slabs and columns on site, reducing costs and speeding up the construction process. The types of formwork used for construction are dependent on the initial outlay costs, the load-carrying capacity of the moulds as well as the intended number of uses.  

Then and Now – A Brief History

Formwork first found its roots in Rome where reeds, due to their abundance, were used to create some of the famous and celebrated architecture that still stands today. Learning from the techniques applied back then, timber formwork was introduced and was popular until the Industrial Revolution introduced hardier materials, such as steel, for large-scale construction.

Materials Used in Today’s Construction   

As much as the Industrial Revolution introduced steel formwork, aluminium and plastic have also found their way into construction formwork. Timber hasn’t been replaced in its entirety as it is still commonly used albeit for smaller builds. Formwork can be reusable or form part of the permanent structure, depending on its portability and the frequency of when it can be reused.

Taking product durability and longevity into account, Nhleko Scaffolding & Formwork provides steel formwork for slab and column concrete construction.

Different Types of Formwork, or Shuttering

Timber Shuttering

Timber offers versatility as the formwork can be constructed on-site to any shape or size requirements. It is ideal for smaller projects and is relatively lightweight compared to steel and aluminium. Although timber is readily available as it is a porous material, the number of uses can only be extended for a certain amount of time before having to be replaced. Timber needs to be treated beforehand to prevent an uneven surface finish and for the possibility of termites.

Aluminium Shuttering  

Having lower density than steel, aluminium, as its previous counterparts, is lightweight and therefore easier to transport. Unlike steel, once the plate has been designed for a specific size and shape mould, it is not possible to alter the formwork plates. Due to aluminium’s makeup, it cannot be used for heavy concrete work as it bears low strength properties.  

Plastic Shuttering

Relatively new to the construction game, plastic formwork is still trying to gain a foothold. It has the advantage of multiple reuses and being precast into various sizes and shapes. It is light in weight and easy to install and strip, giving concrete smooth and precise angular or circular finishes. The load-carrying capacity of plastic formwork is quite low and the initial cost factor may put the project way over budget.  

Steel Shuttering

Steel has been used in concrete formwork since the early 1900s, replacing timber for large-scale construction. The initial financial outlay for steel may not be considered viable for smaller builds, however, it is the most cost-effective material to use in the long run due to its strength, durability and multiple re-use options. It can be used for circular, curved and straight structures offering a smooth and clean finish. The load-carrying capacity of steel is higher than its other counterparts, making it the most popular concrete formwork. Steel can be reused over many applications, it can be fitted and removed with ease and as a non-porous material, there is little or no honeycombing effect. From a cost perspective, the initial outlay is expensive, however, due to its strength and durability, the reusing options are worth it.

The Design Makes the Structure

Formwork forms an important role in the structural integrity of a building. Bridges, towers, piers, commercial and industrial buildings as well as residences, to name but a few, are reliant on various designs of formwork to build usable and safe structures. Formwork can be classified based on the following criteria:  

·         The cross-section. Is it circular, rectangular, L-Shaped, T-shaped or X-shaped?

·         On length and behaviour. Is it being used for long or short formwork?

·         On load capacity and longitudinal reinforcement. 

Regardless of the formwork chosen, quality and durability should never be questioned. Steel should always be the first choice.