2 raw clays samples from Burkina Faso were analyzed in order to improve the ceramic process of roof tiles and small bricks manifacture. The major phases etected by X-ray diffraction in the 2 samples are kaolinite, illite, orthose and quartz. In addition, feeble quantities of albite and montmorillonite are also detected. The thermal behavior between 25°C and 1100°C studied by DTA and DTG is mainly explained by the individual role of clay minerals in studied samples. The sintering of clay ceramics at 1100°C was characterized by dilatometry. In general, dilatometric curves shapes are characterized by successive stages of strain and/or densification in specific temperature ranges. The extend of the observed phenomena is mainly related to the clay mineral fraction in samples. It evidences that clay mineral have a critical role in the sintering of ceramic. A useful application of the terra cotta is found with roof tiles manufacture which imbibition rate and permeability during rain are connected with microstructure and porosity. The microstructure of sintered clays is studied by SEM and the open porosity and permeability are determined. In general, the distribution of size and open porosity appears to be similar in both materials and composite microstructures are evidenced with large grains embedded in a sintered clay matrix. But local heterogeneities are observed in one of the ceramics at interfaces between large grains and matrix phase. They are supposed to have an effective role in pore connectivity through the material. It confirms the importance of pore morphology and connectivity in ceramics, induced mostly by clay type and the sintering process.