In this study, the potential of utilizing natural fibres in construction substances is studied such as the compression strength and heat conductivity. Gypsum walls are reinforcement using sisal fibres for the industrial and construction applications. The sisal fibre has been washed by fresh water and treated with concentration of NaOH (6%), to achieve a real interfacial adhesion between the gypsum and sisal fibres. To survey the impact of different volume fractions of glass and sisal fibres on the conductivity of gypsum, a newly designed heat conductivity test setup was developed. Also, compressive test was carried out for the selected materials. The scanning electron microscopy (SEM) is using to figure out the failure mechanisms by examining the samples after compressive test. The test outcomes detected that the addition of fibres to the gypsum matrix enhances the compressive strength and led to minify brittleness. The optimum fibre content for sisal fibre-gypsum composite and glass fibre-gypsum composite are at 25 vol. and 30 vol. %, respectively. The pure gypsum samples have achieved the highest value of thermal conductivity among other composite samples in thermal conductivity test. The thermal conductivity of the composites reduce with the increase of fibre volume fraction for both glass and sisal addition of the fibres. Due to porous nature of sisal fibre-gypsum composites, as the presence of air voids work as traps and impeded the heat transfer, sisal fibre-gypsum composites performs better than glass fibre-gypsum composites as an insulation material.