Multi-deep storage systems have seen many implementations in warehouses due to their high floor space utilization. Setting the optimal lane depth for the incoming products has a considerable influence on the space utilisation and the storage efficiency, as well as the layout of the storage zones and the selection of the storage modes, the handling equipment and all the induced costs. Conventional models in designing block stacked warehouse assume uniform and deterministic inflow and outflow of products in specific quantities and time intervals. These assumptions would lead to underestimate the space required for each specific case. In this study a recursive model is developed to address the decisions of the combination of single-deep and multi-deep lanes of different depth of a warehouse when flow of products is stochastic and dynamic in nature. Furthermore, the model gives additional value to the designer to maximize warehouse space efficiency, and thus, diminishing the costs. The main objective is to find out the combination of single-deep lanes and multi-deep lanes with different depths that make up the storage system.
