Saving on time, money
Experts feel pre-cast technology could solve housing problems for the economically weaker sections, despite limitations in additions, alterations and repairs.
How green are pre-cast buildings? Not an easy question to answer considering the specific advantages of conventional and pre-casting techniques. In sites difficult for normal approach, pre-casting even appears to be a better solution!
Putting up a factory for pre-casting with moulds, mixers, slab spreader, wall casting chambers and such others is capital intensive, which adds to the embodied energy of the product as well. Nearly all the elements except foundation can be produced in factories including wall, column, beam, stair, floor, roof and sunshades.
Ease of transportation for on-site erection and buffer space to work within the site is important, demanding consideration during feasibility study. Instead of all pre-cast components, judicious mix of on-site work and masonry construction where needed can save both money and time. The foundation, anyhow, has to be done completely at site. Taller the building, more the project cost due to the increased expenses towards lift and lead. Also to consider are provision of services, pre-planning them within the structure.
Fixing the components at heights can be dangerous despite advanced hoisting equipment and personal safety measures. Attractive multi-dimensional shapes and forms are better avoided considering the difficulties in casting and erecting. Certain forms like long cantilevers are nearly ruled out.
Building plans have to respect specific modules, alignments and load points, preferably based on the available sizes and moulds at the factory.
Among the advantages of pre-casting, project time is a major saving, besides optimising the elements with reduced wastage. With the controlled environment for production, precision, quality and strength can be achieved as intended.
The smoother pre-finish may eliminate plastering, saving money or varieties of surface finishes can be achieved.
Structurally, load bearing walls can replace frame construction, where possible, saving additional money. For large span structures, pre-casting is better with the options of pre-stressing to save on materials.
For crowded areas
Pre-cast technology is best suited for crowded areas, where conventional construction would pose major problems.
Presently, it is a costlier option due to minimal and centralised production, but in case of widespread popularity, the costs may reduce. Slowly, apartments, schools and commercial structures have started opting for pre-casting to save time, which in turn saves money.
Pre-casted buildings cannot be customised for every owner’s need; as such it is better suited for mass housing and public buildings where individual aspirations play no role. At present, the technology is so dependent on expertise; the idea will take time to settle down with masses. Many experts feel that it could solve housing problems for the economically weaker sections, despite its limitations in additions, alterations and repairs.
Pre-casting is a harbinger of hope, though not very green in its concept. By scaling up the operations, it has the potential to be an eco-friendly option in some given contexts.