In-situ concrete is the traditional form of concrete construction. Until the early part of the 20th century it was the main method used.
While in-situ concrete above ground level is used less in New Zealand with the advent of precast systems, it still widely used in many other countries.
Systems are being developed and used in both Europe and the U.S. to allow cast-in-place concrete to be cost and time efficient.
In developing parts of the world, in-situ concrete, which relies on higher labour input than other forms of concrete construction, is still dominant.
Cast in-situ concrete has become a material that designers exploit for its structural qualities above all else.
The chance to cast monolithic building elements - walls, columns, beams, suspended floors and roofs which are beautifully detailed - appeals to many designers both in New Zealand and offshore.
The work of Le Corbusier, Louis Kahn, Carlo Scarpa and more recently Tadao Ando in Japan is familiar to many.
The perception of their work is very closely linked to their ability to exploit the qualities of in-situ concrete, which can be summarised as:
- A limitless flexibility of size and shape with no modular restrictions.
- A wide variety of surface textures and colours can be achieved.
- Ability to be cast as a 'sandwich' incorporating an integral polystyrene sheet insulation.
- A robust material which does not require much maintenance.
- A universally available material.
- In New Zealand it is often not cost effective to design traditional load bearing cast-in-situ concrete structures in the face of competition from precast and modular systems.
There are however some simulations where in-situ is the ideal structural material, such as building sites that have difficult access.