Treatment of Thatched Roofs

It has been stated earlier that nearly 612 million people of India live in its 557,000 and odd villages, and over 40 percent of the rural houses are built with thatch and timber roofs. These houses are constantly exposed to fire hazards. The continued action of fungi and bacteria reduces the durability of the roofing materials and thus, the roofs require frequenter replacements. 

The continuous maintenance cost required for these rural houses can be crippling to the survival of the poor householders who may have only some sort of cottage industry such as weaving for livelihood. Even though the National Buildings Organisation has been pioneering the use of chemicals to improve the fire-resistance of thatches, there is very little of preservative treatment for thatches, straw, grass, palm leaves etc. available in practice. 

A number of terms such as fire-proof, fire-retardant and fire-resistant materials are in use and they have been used interchangeably. A material which is fire-proof is rare indeed, and the word 'fire-proof' connotes total unaffected by fie. On the other hand, fire-retardant and fire-resistant materials have drastically lower inflammability; they bum slowly and do not spread the fire rapidly; but they too are substantially altered and eventually consumed by the fire. The .words 'resist' and 'retard' imply partial but not complete barrier to fire; but this barrier may save lives and may delay the spread of fire until help arrives. 

Fires occur quite frequently in villages due to the fact that cheap fuel in the form of loose combustible materials such as dry leaves, dry twigs and sticks giving rise to flying embers; and fires also spread due to the fact that rural houses are built with low ceilings. When such fires occur, more often than not, they spread fast engulfing the entire village, causing loss of or injury to human lives and cattle and damage to property. Yet no effort has been made to adopt fire-retardant treatments to existing thatched roofs. You as a rural engineer, can render a valuable service by popularizing fire retardant treatments which are really simple, cheap and effective (CBRI, 1981).