The thermo-physical properties of some varieties of sawdust and some additives are presented. They are thermal conductivity, heat capacity and specific gravity. The methods of investigation used are Lee’s Disc Apparatus, heat balance and gravimetric method respectively. The sawdust specimens were obtained from six varieties of wood. The additives employed on two typical sawdust samples are cement and silica clay. The values of thermal conductivity range between 0.440 and 0.204 W/m K, and heat capacity between 58,644.08 and 29,584 J/kg K. The highest specific gravity is 0.256 and the least value is 0.107. It was observed that as the clay content increases, specific gravity and the thermal conductivity also increases while the specific heat capacity decreases.