Thermal Insulation Performance of Clay-Based and Cement-Based Wall Panels in Low-Cost Housing in Maiduguri, Borno State

Thermal comfort in low-cost residential buildings is a critical determinant of occupant wellbeing in the hot semi-arid climate of North East Nigeria, where indoor temperatures without adequate insulation can exceed 42 degrees Celsius during the dry season. This study evaluates and compares the thermal insulation performance of clay-based and cement-based wall panels used in the construction of low-cost housing units in Maiduguri, Borno State. Full-scale wall panel specimens of equivalent thickness were constructed using locally produced sun-dried clay bricks and conventional cement sandcrete blocks respectively. A guarded hot box apparatus was used to measure steady-state thermal transmittance under controlled temperature differentials. Additionally, field measurements of indoor and outdoor temperatures were conducted over 14 consecutive days in occupied rooms constructed with each wall type during the peak hot season. Results indicated that clay-based panels exhibited a thermal transmittance 34 percent lower than cement sandcrete panels, corresponding to meaningfully cooler indoor conditions averaging 5.8 degrees Celsius below outdoor peaks. Time-lag analysis further confirmed that clay walls delayed peak indoor temperature by approximately three hours compared to sandcrete walls. The study supports increased use of earth-based construction materials in low-cost housing programmes in the North East as a thermally and economically superior alternative. Keywords: thermal insulation, clay brick, sandcrete block, wall panel, Maiduguri.