Architectural precast cladding was developed to combine the maximum freedom of architectural expression with the economies of mass production of repetitive precast elements. This concept functions most effectively when architects consult with local CPCI architectural precast concrete producers in the early design stages, and through the complete development of the contract documents.
With this precast-specialist help, proper functional, structural and mechanical features can then be detailed. The results will accurately reflect material characteristics, manufacturing and erection efficiencies, cost factors, quality control standards, and local trade practices. A continuing dialogue between designer and precaster will ensure the optimum quality of the product, and its economical, efficient installation at the construction site.
Architectural precast concrete can be cast in almost any colour, form, or texture (within budget guidelines) to meet aesthetic and practical requirements. Special sculptured effects can provide such visual expressions as strength and massiveness or grace and openness. The long-term effects of weathering often enhance the appearance of properly designed shapes.
Design flexibility is achieved by varying aggregates and matrix colour, the size of aggregates, finishing processes, and depth of exposure. Combining colour with texture accents the natural beauty of aggregates.
Panel geometry (shape details) has a major influence on fabrication economy and engineering requirements, with overall size and configuration being the most important elements. Generally, the smaller the elements, the higher the cost.
Surface textures range from smooth, through a variety of ribbed, sandblasted and exposed aggregate finishes. Texture allows the natural concrete ingredients to be expressed, provides the mass with scale, expresses the plasticity of the material and improves its weathering characteristics.
Supplementing the freedom of aesthetic expression and economic features achievable with the use of architectural concrete, are a number of other important functional and construction advantages.
- Architectural cladding panels are sometimes used as permanent concrete exterior formwork, thus becoming an integral part of the structure.
- Insulated architectural wall panels contribute substantially to the overall thermal efficiency of a building. Since the thermal resistance of glass is less than that of concrete, reducing window areas minimizes heat gains and losses. In suitable environments, properly designed precast sunscreens help to reduce air conditioning loads.
- Off site pre-assembly of all the components comprising a total precast wall system, including insulation, air gap, flashing, window washing tracks, window sash and glazing can be very cost effective.