Abstract- Insulating ceramic boards are sought in various industries, civil engineering workshops and even inhomesfor numerous uses but its manufacture is quite complex. This research work was aimed at developing a stableceramic material (high temperature bricks) for high temperature applications in building construction. Insulatingceramic boards were made from clay which was the predominant raw material, sawdust, white Portland cement (WPC) and sand by combining the raw materials in different ratios [ A (60% clay + 30% WPC + 10%sand), B(65% clay + 25% WPC +10% sand), C (70% clay + 20% WPC +10% sand), D (75% clay + 15%WPC+10%sand), E (80% clay + 10% WPC +10% sand), F (57.14 % clay + 28.57% WPC + 9.52 % sand + 4.77%sawdust), G(61.90 % clay + 23.81 % WPC + 9.52 % sand + 4.77 % sawdust), H (66.67% clay + 19.05%WPC + 9.52 %sand+4.77% sawdust), I (71.43% clay +14.29% WPC + 9.52 % sand + 4.77% sawdust), J(76.19%clay + 9.52 WPC+9.52 % sand + 4.77% sawdust)]. The raw materials were mixed, the green ceramic materials were formedinamould of 60 × 25 × 2.5 cm, dried at ambient temperature, fired at a temperature range of 900 – 1303 °Candallowed to cold in the kiln. The ceramic boards were then removed and their physical, mechanical and thermal properties determined. Experimental results showed that the apparent porosity values of all the specimens werebetween 55.42 and 67.28% which are in the international standard range (ISO 5016-1986) of 20 - 80%. The bulkdensity values of all the specimens were between 1.63 and 1.71 g/cm3 bringing them closer to the British standardrange (BS, 1902 part B 1976 ) of 1.71- 2.1 g/cm3 . The thermal conductivity values of all the specimens were between 0.31 and 0.94 W/m.k which fall in the ASTM specifications (C177-2023) of 0.01-1.1 W/m.k except for specimen A, B, G, and H which had higher values. The compressive strength of all the specimens were between2.27 and 6.66 MPa, complying to the ASTM (C64 -2012) which recommends 1.3MPa as the minimumcompressivestrength value for insulating ceramic boards. None of the specimens absorbed more than 20%water of its ownweight in conformity with ASTM (C140-2020). All the specimens had very high specific gravity values not complying with the ASTM (D792 - 2017) range of 2.6 - 2.7. Based on these results, it can be said that specimen I(71.43% clay +14.29% WPC + 9.52 % sand + 4.77% sawdust) is a good substitute for imported insulating ceramicmaterials used for high temperature application in building construction. Keywords:- Local materials, insulating ceramic boards, physical properties, mechanical properties.