Porosity plays a role in the production of gypsum-based composite, especially in gypsum board or drywall. Drywall production is associated with the need for excess water in dissolution and workability of the homogenous slurry. As the homogenous slurry hardened, the liberation or evaporation of excess water in the mixture as well as the entrapment of air bubbles during mixing and pouring process are known to produce composite with high porosity presence. The high porosity has negative impact on the physical aspect of the composite. Red Gypsum or RG is used in this study to produce a low-porosity gypsum composite with respect to water absorption, density, and weight. Results show that addition of RG at 10% is able to improve the density, porosity, water absorption as well structure morphology of the composite produced compared to control samples of 100% NG. However, the properties measured start to deteriorate at 20% replacement percentage of RG and higher. These improved physical attributes are paving way for RG to be used consistently as a secondary constituent in the production of drywall insulation composite, thus reducing the dependency on normal gypsum significantly.