Gantt Charting 101

Gantt Charting 101

Organization is extremely important when bidding and planning large jobs. Being able to effectively estimate the flow of a job and determine how long different aspects of the job will take. One tool that’s often used for this is the Gantt chart. When properly created, one of these charts can tell you at a glance both how long an entire job should take and where each aspect of the job falls within that time span. If you’ve never used Gantt charts in your jobs, here’s what you should know to get started.

What Is a Gantt Chart?

A Gantt chart is a type of bar graph that’s used to represent the schedule of a job or project. The x-axis of the chart shows time intervals, often divided into weeks or months, sometimes even into days; the starting point of the axis is typically the beginning of the job or project, and the end of the axis is either the end of the job or a specified period after it ends. The y-axis shows individual tasks that are part of the job or project, breaking the project down into the various specific parts that must be completed during the work period. Using these as guides, bars are placed to indicate tasks being worked on over time.

Task Representation

The bars on the chart represent the time that each task is expected to take. It’s worth noting that the bars don’t run from the beginning of the chart until their expected completion time; instead, each bar is only present during the period when your crew will be working on that task. This lets you see where each task falls within the overall workflow of the job or project and how long the task should take compared to the overall job. Tasks should be placed in order of priority from top to bottom, though if the job needs to be separated into phases, then tasks should be listed in whichever phase is appropriate.

Reading a Gantt Chart

Because phases are listed in order and tasks are prioritized within each phase, a Gantt chart should generally represent a time-flow across the job when read from the top left to the lower right. While multiple tasks may start at the same time and tasks with different lengths may stagger oddly, the task at the top of the chart should be the first thing undertaken and the task at the bottom should be the last. Arrows and other notations may indicate dependencies on the chart (indicating that two tasks should start together, finish together or that one must finish before the other can start), with the arrows pointing from either the start or end of one bar to the start or end of the bar that has the dependency.

Creating Gantt Charts

There are a number of tools available to create Gantt charts. It’s possible to draw a chart by hand, though a more professional approach is to use software such as Excel, Visio or other project management software. If you use word processing software that features the ability to make inline spreadsheets, this can be used to create a basic Gantt chart for use in proposals as well. Regardless of the tool used, make sure that your tasks are properly labeled, your timeframes are well defined and that each bar is positioned and shaded well enough that you can easily tell which bar corresponds with each task.

Have you ever used Gantt charts for your bids or general workflow?