Map Metra

Program 3: Constraints, float and the critical path

Part 3 of the Program series. Understand the critical path and float in a construction programme, pin start dates, set deadlines, and filter the Gantt chart to the critical activities in Map Metra. Everything shown can also be done by asking the Map Metra connector in Claude or ChatGPT.

How to

  1. 1

    Pinning a start

    Sometimes an activity can't start before a certain date, such as site access. Type a date in its Start cell to pin it.

  2. 2

    Clearing a pin

    To remove it, right-click the row and choose Clear pinned start. The programme goes back to its linked dates.

  3. 3

    Moving a bar

    You can also drag a bar along the chart. Here, the downpipes move a few days later, which pins their start.

  4. 4

    Deadlines

    Enter a deadline for any activity. If practical completion has to be by the twenty second of January, the float turns negative, and the finish is flagged in red.

  5. 5

    Float

    Float is how many working days an activity can slip without delaying the finish. The party wall and the downpipes have float.

  6. 6

    The critical path

    Activities with no float form the critical path. Switch the toolbar to Gantt, and Design turns the critical path colouring on or off.