Abstract: The construction element comprises two different parts. A first bearing part (1) has cavities of cylindrical cross-section with rounded ends and is constituted by light concrete having a resistance to compression comprised between 25 and 175 kg/cm.sup.2 and an apparent density comprised between 900 and 1250 kg/m.sup.3. The second insulating part (2), of an apparent density of at most 270 kg/m.sup.3, is constituted of an hydraulic binder based on cement, a synthetic resin and an expanded mineral filler. The heat transmission coefficient k in the direction perpendicular to said parts of the monolithic element is less than or equal to k=0,40 (W/mK).