The entire world is facing significant energy consumption in the form of electricity by use of air conditioners, for maintaining human comfort temperature. In order to minimize the energy consumption, gypsum boards are used as roof ceiling material in buildings that prevents the thermal penetration to a limit. The current study reports the enhancement in thermal properties of gypsum board with the addition of expanded vermiculite as a partial replacement to gypsum powder with gypsum to water ratio as 1:0.8. Here the expanded vermiculite is incorporated into gypsum board by replacing gypsum powder with 0, 10, 20, 30, 40% by weight in order understand the thermal performance of gypsum board. A glass fiber mesh was placed at the mid layer during casting, in order to increase the mechanical strength. Further mechanical test such as compressive strength test and flexural strength test was carried out for all percentage of replacement. The compressive strength and flexural strength of the gypsum boards are effectively assessed, providing valuable insights into their potential applications in construction. Thermal conductivity of various ratios of vermiculite incorporated gypsum board was analysed, in which 30% replacement of gypsum powder with expanded vermiculite possess lower thermal conductivity. This study concludes that addition of expanded vermiculite improves the insulation property of gypsum board, as its thermal conductivity value is lesser as compared to normal gypsum board.