The energy consumption of the buildings for cooling, especially during the days of high solar exposure is large due to the increased indoor temperature. The roof of the building contributes more for this cause by allowing a large quantity of heat during day hours. Further, the single storey buildings with the metal roof would help to penetrate a greater quantity of heat and increase the total heat gain of the building. In this way, they could increase the cooling load to attain the human comfort. In this current work, an experimental investigation was carried-out to reduce the indoor temperature of the metal roof single storey industrial building with the help of paraffin based phase changing material (PCM). In this fashion, an attempt was made to reduce the total cooling load of the building which can diminish a greater quantity of conventional power requirement. A scale model of the proposed building was fabricated and tested for the analysis. The experiments conducted in two modes such as the first case without any PCM in the roof (Plain Roof) and next case with encapsulated paraffin as PCM within the roof (PCM Roof). The test results proved that the encapsulation of PCM within the metal roof of the single storey building reduced the temperature of the outer roof, inner roof and consequently the indoor temperature of the building space to a vast extent. Quantitatively, the daily average indoor temperature was dropped by 5 °C and peak indoor temperature was reduced by 9.5 °C with the help of PCM.