Construction Scheduling. Are you using Calendars Appropriately in Your Project Schedules?

excalmation-markDo you understand the need to develop specific activity, resource and project calendars? So you put the effort into this process? Do you understand how calendars can help you?

Many, many smaller projects have project schedules with calendars that are set to whatever the default calendar setting is. Typically, this is a 5 day work week calendar with 8 hour work days.

You may ask, what is wrong with this?

Well, the short answer is, you are not allowing your schedule program to effectively schedule the work for you. You should really have a calendar for each different work week, such as a 4-10 hour day calendar, (if you have a resource working this shift). A 7 day work week calendar with no holidays is very helpful for project milestones because the total float is in calendar days. A typical work week calendar with defined holidays and anticipated weather related non-work days is a great way to ensure weather sensitive activities have anticipated “weather days” assigned.

For this post, I will only talk about activity calendars. Resource calendars can add complexity, and must be addressed, but not in this post…

For activity development, I prefer to keep things simple. I use the appropriate calendar, based on the planned work week for the work tasks. This includes holidays and any other don-work days identified in the contract. I develop a weather day calendar, based on the appropriate normal work week calendar to assign to my weather sensitive activities. I use a 7 work day week calendar, with no holidays or any other non-work days for my contract milestones and as the default for the project. This allows the team to see calendar day total float values.

Of course, the use of multiple calendars creates a little confusion when reviewing the schedule. The total float values for a string of activities will be different based on the calendars assigned. The actual start date to finish date durations will not match the “work day” duration assigned. These types of issues confuse many people. But once you use the calendars appropriately, you are letting the schedule better model your plan for the work.

Isn’t this what the schedule is supposed to be used for at its’ most basic level?

What other methods have you found to model and manage work with calendars?

I’d love to hear what you think!

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Paul Epperson CCM, PMP, PSP, PMI-SP