Does the room have to be clear?

No, but it does help if any breakable items (i.e. China, glassware etc.) are removed from the room, including those inside cabinets that will have to be moved. It would also help the technician if small items of furniture are also removed, such as waste paper bins, paper racks etc. The technician will then move the items, clean and put the back in position placing protector pads/fibre blocks beneath the item to prevent staining from loose wood dye or rust from metal studs under the legs transferring onto the carpet.