<p>In steel roof gymnasiums with RC substructures, out-of-plane response of cantilevered RC walls are predominant during seismic responses, which triggers sequential damages of structural or non-structural components. Detailed regulations have been not included in the current Japanese building code yet even though Gymnasium is used as a shelter in disaster. In this paper, a design procedure for out-of-plane response control of a cantilevered RC wall connected by roller supports to metal spatial roof was proposed. While many researchers proposed response evaluation methods for cantilevered RC walls, those methods are too complicated to be implemented in the actual design process. Therefore, the proposed design procedure is carefully formulated based on Japanese structural engineer's practice. The design equation is derived from both equivalent linear approach simulating damping effect and continuum mechanics where a cantilevered RC wall is modeled as single beam or single plate. In Section 2, the detailed design procedure (the scope, the design criteria, the seismic load and the actual design process) is carefully explained for engineers. In Section 3, the derivation process from the response evaluation to the design equations is explained. Both single beam and single plate are modeled as secant bending stiffness of RC members yielding. In Section 4, the response evaluation values are compared with the numerical simulation results of the actual damage gymnasia. In Section 5, the response evaluation values are compared with a shake table testing of 1/2.5-scaled model of school gymnasium. In summary, the following results were obtained:</p><p>1) Both of single beam model and single plate model are more accurate than simplest formulas of cantilevered beam against non-linear response history analysis results of the actual damaged gymnasia. The single beam model is suitable for a cantilevered RC wall where span is long and the bending stiffness of beam is negligible. The single plate model is suitable for a cantilevered RC wall where span is short and the bending stiffness of beam is not negligible. Threshold value is 0.409 of the coefficient q determined by both width-to-height ratio L/h_c and bending stiffness ratio D_y /D_x .</p><p>2) The static stress analysis results of numerical frame model composed of only the cantilevered RC wall was corresponding to the non-linear response history analysis results of the damaged gymnasia with no friction dampers.</p><p>3) The response evaluation results of the single beam model was corresponding with error 10mm to 15mm to the shake table testing results.</p><p>4) The response evaluation results of the simplest static formula of a cantilevered beam were too conservative compared with the others, and may produce uneconomical design.</p>