<p>Developing countries with a high growth of young population are often faced with the burden of a housing deficit. Manufacture and utilization of locally abundant natural materials in building services remain the most viable option in mitigating such challenges. However, environmental safety and public health concerns due to toxic pollutants in such construction materials should be given priority attention. The need to develop local sustainable construction materials that meet the United Nations’ 2030 target for Sustainable Development Goals (SDGs) necessitated this study. Agbani has large deposits of quality clay minerals that have been studied. The authors blended and reinforced Agbani clay with granite to produce composite clay materials that can be used in building services. The samples were heated to 900 °C, 1000 °C, 1100 °C, and maximum temperature of 1200 °C. XRF, XRD, physical properties, mechanical behaviour, and physicochemical properties of the samples were characterized using different combined experimental techniques. The result of the XRF analysis shows that SiO₂, Al₂O₃, and Fe₂O₃ constitute the major oxides while the XRD analysis shows that quartz, orthoclase, kaolinite, and albite dominate the mineralogical composition of the clay. The results of the physical properties of the Agbani clay deposit suggest remarkable improvement in the physical properties such as apparent porosity, bulk density, and water absorption with the addition of granite and firing at 1200 °C. Mechanical property results show that impact strength, impact energy, modulus of rupture, and compressive strength all increased with the addition of granite and firing to elevated temperature. However, the plasticity limit was adversely affected as it reduced. For all the clay samples produced, blending them with granite and firing at 1200 °C led to a significant reduction in the toxic materials such as lead, mercury, arsenic, phosphorous, and chloride.</p>