‘Bpri’ (Burnt-Pot Roof Insulation), the Novel Method of Roof Insulation in Bangladesh

Abstract

The roof of the building needs insulation for thermal and humidity purposes. In Bangladesh lime-terracing is used for this purpose. Mortar made of slaked lime and powdered brick (local name: surki) is applied on the reinforced roof in 100 mm layer. It works fairly well in the situation where the variation of internal and external temperatures is low. In Bangladesh this variation in the naturally ventilated rooms is not over 3○ C and lime terracing shows a time lag of about 5 hours at this range. Some of the problems of the conventional Lime terracing are (a) It is costly, (b) It allows heat leakage when atmospheric temperature rises above 35○ Celsius and also when there is wide variation in internal and external temperatures due to air-conditioning of the room. The authors of this paper devised an alternate system. In this system air pockets were provided inside the layer such that it became lighter, consumed less material and had more insulating properties. The air pockets were provided by using burnt clay pots available in the market. The system was named Burnt-Pot Roof Insulation, abbreviated as BPRI. It was first applied in Khulna, Bangladesh in the year 2002. The cost of construction was only 10% of the cost of conventional lime terracing. The system at present is having increasing use in the country.