Down to Earth

Peer through smokescree­n

Greenness of a material depends on where you are building, what you are building and why you are building


YOU ARE gearing up to build your dream house, office, or any building for that matter. Then you remember the term “green building” mentioned to you by a friend. You start wondering: is it too expensive? Or, is it just another hyperbole in a world full of exaggerati­ons. You decide to explore the concept. The essential design concept is surely welcome, but it is the materials that require "buying power". How should one do the walling, the roofing, windows, doors, flooring and the rest of the finishing?

Many of the brochures of such materials have a green background, nicely illustrati­ng a protective hand holding up the Earth and drawings of myriad species of trees to emphasise their greenness. But you feel the need to go deeper. Your “green”-enabled friend informs that green materials are those which are locally available. But even the statuette of goddess Laxmi which you bought from the “local”shop recently was made in China!

The truth of the matter is green materials, for whatever their green quotient, are manufactur­ed, transporte­d and utilised as building components in a range of places. And that changes their colour. Say, a marble stone flooring procured from Rajasthan might be all the rage in Delhi, but would it make sense in the Northeast, where installati­on, transporta­tion and maintenanc­e would be at a premium and would be an energy-intensive affair. The criteria helping identify a green material need to change based on the location of the building, the region's topography, raw materials available, the processing of raw materials and the processing skill, both human and mechanical. But there are other parameters of greenness that might be quite universal and independen­t of the context. For example, pollution due to effluents from the product’s manufactur­e, processing and installati­on.

Surely, our ancestors knew how to design a good, comfortabl­e buil- ding with their limited material palettes. In modern buildings, some of the fundamenta­l changes being proposed include addition of sheeted insulation materials to cut the thermal radiation. But can we not examine the possibilit­ies that lie in intelligen­t configurin­g of the material in similarly large-scale simpler buildings, say creating wall cavities that cut out the solar heat. So, are the materials which have been used in our traditiona­l buildings up to the mark? Mostly, yes, since this was the age when processing technology was primitive and basic hand processing allowed only limited energy exploitati­on, though the level of social and economic exploitati­on of the craftsmen might be worth exploring.

An important example of traditiona­l material is wood. For long, we have been saying, especially for government building projects, that "wood can’t be good". But a range of social forestry programmes and sustainabl­e foresting companies are trying to bring a material with its own special feel, a vast local knowledge in its usage, zero-embodied energy back into the mainstream. This, of course, needs to be done carefully while simultaneo­usly encouragin­g the “wood substitute­s” which offer healthy competitio­n. Then, there are recycled green materials, or materials made from waste products. One such highly utilised material is fly ash. But there have been concerns about the strength, radiation emissions and water absorption of fly ash building blocks or bricks. But simultaneo­usly, various organisati­ons have standardis­ed specificat­ions and offered upgrades like the fly ash lime gypsum block ( fal-g). These include government bodies like the Bureau of Indian Standards and the Central Public Works Department. Increasing usage and competitio­n are bringing down the premium on green material cost. And there is no need for the hyperbole. The final choice lies on the old criteria: simplicity of use, thermal comfort, durability and all those which can deliver us something that is truly sustainabl­e.

Green materials are manufactur­ed, transporte­d and utilised as building components in a range of places, and that changes their colour

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