Component and facility layout plays an important role in the design and usability of many engineering products and systems as mechanical design, process plan, management and architecture including ship compartment layout,... Because of the great complexity of most industrial layout problems, the decision of the acceptable layout is a hard and critical task since the special layout can have a significant consequence on the user satisfaction, the economic cost and broadly speaking the global performances. Thus, in order to propose to the designer an optimal spatial arrangement in a reasonable time, this paper develops an interactive optimization strategy based on a genetic algorithm coupled with a separation algorithm. The proposed method is tested on the layout problem of a shelter. The resolution of this problem is innovative because it introduces the concept of space of accessibility in the layout problem formulation.