Use 90% of your floor space for storage with mobile racking which is highly compact and can work on either of the FIFO or FILO methods. Here there is no fixed aisle as the racks sit on a mobile base and access is needed the aisle can be created at the right location by opening the racks either manually or through a powered control.  Only one aisle space can be opened at one time so this system would suite low turnover items which require safe storage until picked.