To lay larger floors, a different method is used. The floor can be laid in bays (small squares). Laying the floor this way means that you can step in between each allowing you to get from side to side with ease. Vertical joints should be grouted before laying another section of bays, but you should try not to have too many joints.
A floor that is considered to be level is no more or less than 3mm over a 3 metre distance.