What is Float ?
Definition of Float in Construction
The term float, refers to the overall time between the early start of a construction activity and the late start of the activity, without negatively influencing the overall critical path of the project.
Each construction activity has a date that is the earliest possible time that activity can commence. For example, the shingles on the roof, cannot start until a portion of the roof sheathing is installed. The clever and experienced schedulers realize that the actual shingles could commence prior to the full completion of the roof sheathing. This would be identified as the early start of this item, the earliest date possible for this work item to commence.
However, scheduling the proper timing for the early start requires an understanding of the construction process, to accurately identify the quantity of sheathing that should be installed, prior to the commencement of the shingles. Too little and the shingle installation will catch up with the sheathing and will need to stop, too much sheathing installation, and the schedule will not be maximized for efficiency. The management and understanding of construction activity float is essential to the proper scheduling of any construction project.
Float can be a dangerous concept, due to the tendency of superintendents to understand the float concept only to their advantage, and allow it to be used as an excuse, not to aggressively pursue the schedule. Some management personnel realize an item has significant float time, therefore the importance of its commencement is diluted by the float identification. Float time is where you can maximize the efficiency of a good construction schedule, it is not, free time, to be used as an excuse not to expedite the schedule.