The purpose of this study was to enhance thermal performance of various polyvinyl acetate polymer (PVAc) blended magnesium oxychloride cement (MOC). PVAc polymer was used to replace cement MOC in proportions of 0%, 5%, 10%, 15% and 20%. The effects of PVAc on the thermal properties, mechanical properties, microstructures and the phases of MOC have been evaluated by using Photothermal Deflection Technique (PTD), scanning electron microscopy (SEM), X-Ray diffraction (XRD). Photothermal Deflection Technique allows determining the specimen's thermal property such as thermal conductivity and thermal diffusivity. Thermal property is measured by comparing the experimental curves of photothermal signal to the corresponding theoretical ones. The results revealed that the addition of PVAc has been improved the thermal insulation of the composite. It was observed that the 10% PVAc percentage gives the lowest values of thermal conductivity and thermal diffusivity of the cement. The reason for this reduction may be explained by the air bubble formation in the cement matrix. (C) 2018 Elsevier B.V. All rights reserved.