The increasing demand for housing in Colombia and several neighbouring countries, together with the large relative cost of the materials, has prompted city administrations to build thin reinforced concrete (RC) wall buildings with a single layer of reinforcement. Such members may experience instability and large out-of-plane deformations under seismic action. The existing models idealize the wall boundary element as an equivalent column subjected to cyclic tensile-compressive loading, and past studies have identified the maximum tensile strain applied to the member as the governing parameter which triggers the out-of-plane deformation. The influence of the wall thickness, the reinforcement eccentricity, and the loading protocol, remain largely unaddressed. This paper presents, for the first time, the initial results of the application of a beam-column model — using distributed plasticity and section fibre discretization — to study the above mentioned variables and the influence of boundary conditions, among other aspects.