Last edited 28 Sep 2020

Precast concrete cladding

Precast concrete cladding is formed by off-site manufactured precast concrete panels, which can be used to clad a wide range of buildings, such as commercial buildings, residential, retail, leisure, hospitals, schools, and so on.

Precast concrete is a form of concrete that is prepared, cast and cured off-site, usually in a controlled factory environment, using reusable moulds. Precast concrete elements can be joined to other elements on site to form a complete cladding structure.

The production of precast concrete elements takes place under controlled conditions in factories, and so tolerances can be accurately controlled, waste can be minimised, and that a denser, stronger and better-quality concrete produced.

Due to innovative production methods, precast concrete panels can be manufactured in a wide range of colours, finishes, facings, shapes and sizes. It can replicate the colour and finish of stone, masonry or terracotta and can incorporate architectural details such as cornices, quoins, arches and decorative relief panels.

Sculptured shapes such as recessed windows, shading devices and so on can be included, and insulation can be fixed to the back of the panels, or incorporated into a sandwich wall panel composition.

Panels can be supported by fixing back to the structural frame of the building or can be self-supporting. They can also be designed themselves to parts of the building structure such as floors. Panels are typically in the range of 150 mm thick, designed to span either between columns or between floors.

Panels are manufactured by casting in purpose-built timber or fibre glass moulds. Steel reinforcement cages can be placed in the mould prior to pouring the concrete. Increasingly, prefabrication can incorporate the fixing of other elements such as insulation and windows. When the moulds are removed, the exposed surfaces can be treated in a number of ways, such as acid-etching, smooth or coarse grounding, grit or sand-blasting, rubbing or polishing, according to the surface finish specified.

Having been transported to site, tower or mobile cranes lift the panels into position, with fixings restraining them back to the structure. This means that external scaffolding may not be required.

Precast concrete panels can result in a thinner external wall construction than traditional walls, and so they can allow a larger lettable floor area.