The easiest space to recoup in most every operation is overhead space – the vertical cube. Expanding out costs more than expanding up. Over time, that means utilizing mezzanines, suspended overhead conveyors, pick modules, taller rack systems, the space over dock doors, etc. That space is available in most every warehouse or manufacturing facility, but utilizing it means that you have to be able to move material between levels without creating bottlenecks.
What are your options?