The evaluation of the Nfayil limestones in Bahr Al-Najaf Depression as construction materials was done on 15 sites distributed over a region. The study included field and laboratory aspects. The field side included collecting information about the study area and samples. As for the laboratory side, laboratory tests were conducted to study the thermal conductivity of samples by a device called Lee’s disc in the Tikri University. The thermal conductivity results ranged between 2.34 and 0.27. The rocks are of high thermal insulation at low temperatures and low insulation at high temperatures according to the specifications of the suitability of limestone for thermal conductivity standards (ASTM C 1057-03-2010).

In this research, some engineering properties were studied for samples of fire clay bricks, which were selected from the study area, Dilbat or Tel al-Deylam, which dates back to the Middle Babylonian era 1500-600 BC in the southern part of the province of Babylon within the Al-Kifl district. The samples taken were subjected to many Engineering tests , which is the ratio of porosity, compressibility, density and ultrasound examination (Vp,Vs), from which each of Young's modulus, Poisson's modulus, Bulk modulus, Shear modulus was extracted, where the average porosity (23.06) which ranges (27.30-18.53), density (1.09 ) ranges (1.52-0.89), water absorption (20.86) ranges (26.17-15.94), compressibility (5.10 ) ranges (9.96-3.31), Vp (1053) ranges (2410-350),Vs (737.1) ranges (1687-245), Young's modulus (1.89) ranges (8.82-0.11), Poisson's modulus (0.013) ranges (0.013-0.013), Bulk modulus (1.89) ranges (8.82-0.11), Shear modulus ( 0.92) ranges (4.32-0.05).