Stabilised sandcrete (sand-cement) and latscrete (clay/mud-cement) blocks are the most commonly used materials for masonry building walling material in Port Harcourt metropolis. Despite the hot, humid tropical climate in this region, the interior thermal comfort benefits of selecting suitable walling materials for buildings are frequently overlooked. In addition to the interior thermal comfort in buildings, rising energy usage is also a cause for concern. The choice of material for wall building is influenced by cost, strength, and durability. However, interest in employing sustainable green architecture and thermally comfortable building materials has increased in recent years. Selecting appropriate wall materials that can be energy efficient and lower cooling load is necessary, since external walls play a significant role in thermal insulation. Therefore, the study evaluated indoor thermal comfort, comparing commonly used stabilised latscrete blocks as walling material in two model buildings. To evaluate the characteristics of the two walling materials, a series of tests were performed to determine the water absorption rate, compressive strength, splitting tensile strength, and flexural strength, following the standards set by the American Society for Testing and Materials (ASTM). Readings of relative humidity and indoor temperature of the two buildings were respectively taken and recorded for a period of twelve months. The data were collated and analysed using the Temperature-Humidity Index (THI), Heat Index (HI), and Effective Temperature Index (ETI). To compare the thermal comfort performance of the building models, the ASHRAE 55-2020 standard scale was used. Latscrete was found to be a better thermal comfort performer than sandcrete and was, therefore, recommended as an alternative local walling material for building in the study area
