Formwork

‘Formwork’ is the term used to describe the fabrications and constructions used to form the shape of concrete structures, acting as the mould. It is normally removed once the concrete has achieved sufficient strength, although it is sometimes left in place as permanent formwork, which may or may not contribute to the structural capacity of the formed concrete. Formwork is either vertical (for walls, columns, beam sides, etc.) or horizontal (for supporting slabs, cantilevers, underside of beams, etc.). Horizontal formwork is described in Chapter 24 on soffit formwork.

Traditional formwork is fabricated using timber-based materials but steel, glass-fibre- reinforced plastics (GRP), glass-fibre-reinforced cement and other materials are also used. Proprietary formwork includes the walings, bearers, soldiers, supports and various panel systems and is available from specialist formwork supply companies. Choice of material is often based on the required number of uses of the formwork and the finish specified for the concrete by the Permanent Works Designer, with more expensive materials often justified by more onerous surface finish and durability requirements for the concrete.