ABSTRACT: The Unreinforced Wall (URM) elements that are most susceptible to out-of-plane failure are wall elements of the upper storeys where the accelerations are largest. In modern URM buildings with reinforced concrete slabs, the out-of-plane mechanism involves typically a storey-high wall element, which is subjected at its base and top to the accelerations of the corresponding floor slabs. The acceleration time histories of the two slabs differ as a result of the deformability of the in-plane loaded walls and their rigid body rotations. Existing studies on the out-of-plane response of URM walls analysed walls that were subjected to the same input motion at the top and bottom of the wall.