I'm stuck with an issue with scheduling my construction project.

A concrete slab pour takes only one day to complete and we pour two floors a week, every Tuesday and Saturday (3-day schedule). I set up Saturday as a workday in the settings already.

The 26th Floor is the first date (5/3/17) which I inputted manually because I need the rest of the floors to auto schedule from each other.

In the example below, please help me figure out what my formula should be in the predecessors column and if I need any constraints.

The first error as you can see below is on the 30th floor slab pour. The finish date needs to say "Say 5/13/17".

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  • 1
    Format the date columns so that time is also displayed. The task might not be starting at the beginning of the day. Also look at your constraint date. May 4, 2017 at 19:02
  • 1
    Also, get rid of all manual tasks; use a SNET constraint instead. Why is 3117 only 1hr instead of 1 day. Too many issues going on here to comment further.
    – Tom Boyle
    May 4, 2017 at 19:20

1 Answer 1


If those tasks should be done always on Tuesdays and Saturdays, then you can create a calendar with only Tuesday and Saturday as working days. Then, assign this calendar to these tasks, and modify the relations as “Finish-to-Start” with no lag. Just make sure that every task has a 1-day duration (task 3117 is 1-hour only).

Hope this helps.

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