Trusting builders is only option left for buyers in Bangalore

Who monitors what goes into the construction of new buildings? Town planners and civic analysts say that there are two things used in construction that we need to be wary of: filter sand, which is often passed off as sand from a river, and ready-mix concrete, which could also be made with ingredients of poor quality.

There is reason for skepticism among those seeking to buy property not only in Bangalore but elsewhere in the state too.

Ever since the clamp down on illegal sand mining, filter sand that is sourced from artificial water bodies and often has a high proportion of clay, has become a more common substitute.

The high proportion of clay in the sand adversely affects its ability to bind material.

Earlier, sand was sourced from Maddur, Kolar and Chikkaballapur for construction work. Of late, sand is also illegally mined in North Karnataka and Andhra Pradesh; this practice is now under the scanner.

“Scarcity has pushed construction companies to opt for filter sand mined illegally. This trend in the construction business is not new, it started about four years ago when the sand scarcity first started,” said K Sreedhar, chairman, Builders’ Association of India, Bangalore chapter.

Ready-mix concrete is commonly used in construction, and even reputed firms use it. However, sand is one ingredient that goes into its manufacturing process, and it is often quite difficult to test the quality of sand used in this variety of concrete. “Who knows what kind of sand is already mixed? Sometimes, powders and clay get into the ready-mix concrete, and even seasoned construction firm employees would be hard pressed to figure out the quality of the mix. It is only if a mould is made and tested in an accredited laboratory that the true quality of the mix will be known,” said Naresh Narasimhan, principal architect, Venkataramanan Associates.

“How much knowledge is it fair to expect a buyer to have in this matter? The buyer, after all, often only sees the finished product. Generally, reputed builders have their reputation at stake, and will use only good quality material; that is also why they quote high prices,” said K Sridhar, president of the Bangalore chapter of the Builders’ Association of India.

There are, however, common tests like the sieve tests which reveal the proportion of silt in sand. If more than 10% of the sand is silt, it cannot be used in construction.

There are cube tests that can be conducted on ready-mix concrete. A mould is made, and then sent for tests in a laboratory. There are standards and procedures laid down for professionals in the real estate business.

The sand scarcity has been caused by extensive building activity, and there is need to monitor all construction more closely, say town planners. “It is not a question of the quality of construction material alone. There is little supervision of building works in the city, and even the quality of many works executed leaves much to be desired,” said Dr AK Kodandapani, town planner and civic analyst, warning that buildings constructed with filter sand would be weak, and liable to collapse.