Isotex blocks for the construction of non-load-bearing infill walls are used in structures with pillars and beams. These blocks have an increased thickness of insulating insert in Neopor® BMBcert from BASF to reduce the thickness of filling concrete cast in works to 12 cm. The non-load-bearing walls are so lightened compared to the load-bearing walls that they must instead have a minimum concrete thickness of 15 cm as required by the legislation.