In part one, we discussed the project management concepts of Work Breakdown Structure (WBS) and project scope development—or the “what” of the project. In this part, we will discuss the schedule, or the “when” of planning. The typical steps to create a schedule include: defining the task, sequence of tasks, estimate resources, estimate durations, develop the schedule and manage the schedule.
Define the Tasks
Use the WBS as a starting point for this task. You will need to take input from other sources, such as the contract, building plans and local codes. Once you’ve defined all tasks, define the actual activities required to create each set of deliverables. You may also consider expanding the number of activities required, especially for complex or involved tasks.
Based on past experience, or because the relationships are fairly clear, you may have a good idea of the sequence of tasks. [Examples include pulling permits, demolition, plumbing and electrical.] Before starting any work, understand how the schedule will be used, who will be using it and how it will be updated.
When selecting a presentation method, you need to consider project complexity; which planning software you are using, if any; and how to share the schedule. Some common display types include a flow chart (also called a network diagram) or a bar chart/Gantt chart.
Prior to laying out the schedule, you will need to classify your tasks as predecessor or successor tasks. Predecessor tasks are those that occur before another task, while a successor task is one that occurs after another task. These relationships generally reflect the required sequence that will be applied in the schedule. Task dependencies can have one of four different conditions:
- Finish to Start (F-S): The first task must finish before the second task can start. F-S is the most common task.
- Finish to Finish (F-F): The first task must finish before the second task can finish.
- Start to Start (S-S): The first task must start before the second task can start.
- Start to Finish (S-F): The first task must start before the second task finishes.
Next determine the resources required/available for the project, including funds, workers and equipment. If you use trade contractors, factor in their capability and availability at this point. If you find gaps in resource availability, now is the time to resolve.
Determine the time required to complete a task and assign it in the duration. The methods used to arrive at these values can range from a guess based on past experience—e.g., “It always takes a week to hang cabinets”—to other more complex techniques. You can also make an estimate and add a safety buffer or average the best and worst case times.
Develop a Schedule
First lay out the tasks, then factor in labor and trade contractor availability, and make adjustments. If a project can be affected by outside conditions like weather, material shortages or trade contractor delays, factor that in as well.
Critical Path Method (CPM)
In this method, you plan tasks by duration and dependencies. The longest path becomes the critical path because it defines when the project can be completed. It should be noted that as the project moves forward, changes to tasks’ lengths due to unforeseen issues may extend an alternate path and make that the critical path. It is very important to manage each path and understand the current critical path to ensure completion dates stay on track.
Bar Chart/Gantt Chart
This is a common presentation tool and is often the default for software tools. It provides differing levels of detail and can be compact, showing a lot of data on a page. However, it can be harder to show the task dependencies than a project flow chart or network diagram.
Milestones are major deliverables or decision points of a project and may include completion points, transitions in work, or phases related to payment. [Examples would include design completion, pulling permits, demolition starts and framing inspection.] A milestone schedule provides a concise view of the entire schedule by identifying these key events.
Manage the Schedule
Once the preliminary project plan is completed, you have a baseline schedule, but it is a living document. Once work begins, it should be referred to and updated as changes occur.
Things happen, like weather, product delivery delays, sometimes a sickness or other unforeseen issues. It’s important to document any situations that may result in a change in schedule. Approved change orders or a rain delay require an update to the project timeline. |QR
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