Construction projects require meticulous planning as they involve numerous tasks and resources that need to be coordinated effectively to ensure timely completion. However, according to a new study, approximately 63% of top U.S. contractors are completing projects late. And, delays in one aspect of the project can have a domino effect, causing setbacks and ultimately costing time and money.
In order to successfully manage a construction project, it is crucial to understand how the CMP construction schedule works and how to utilize it effectively to keep everything on track. In this blog, learn how you can ensure that your construction project stays on schedule and is completed successfully and efficiently with a CPM schedule.
What is a CPM construction schedule?
The Critical Path Method (CPM) is commonly used for construction scheduling. It compares construction tasks, prioritizes them based on their impact on the schedule, and identifies the critical path. For instance, tasks on construction sites often happen simultaneously, such as HVAC, structural work, and landscaping work. Although all tasks must be completed, not all are essential for keeping the project on track.
A CPM schedule provides early and late start dates for each project, highlighting the longest activities while ensuring all critical tasks are completed on time. These schedules are visualized in network diagrams, making it easier to prioritize critical activities.
Many construction professionals and project managers consider CPM the most practical scheduling method. Various online project management tools are also available to manage projects with multiple activities efficiently.
What is a CPM construction schedule used for, and how does it work?
The CPM construction schedule is crucial for sequencing activities in the right order and establishing possible start and finish dates for each one. The critical path can be identified by applying these time frames to a schedule. This path consists of activities that can impact the project completion date if they are delayed.
However, scheduling is not just about duration and deadlines. Data and resource allocation can also help improve scheduling accuracy for future construction projects. Additionally, construction managers use CPM schedules to identify and avoid bottlenecks, such as market disruptions, that could impact project timelines and performance. By knowing which tasks can be run in parallel, contractors can prevent delays and keep projects on track.
7 benefits of using CPM construction schedule
CPM scheduling for construction offers a range of benefits that can help construction companies better manage their projects, increase productivity, and reduce costs. Let’s take a look at those benefits below:
- Provides Easy-to-Understand Schedules Through Visualization: A CPM schedule helps by keeping teams aligned and making sure everyone is aware of deadlines and urgent activities. This helps the team with a diagram that is simple to understand and shows the connections between tasks, improving communication and urgency.
- Saves Money: Adhering to the CPM schedule helps contractors and managers finish projects on time and stay on budget.
- Helps Prioritize Construction Tasks: The CPM schedule helps identify changes in completion times of construction activities that could impact the critical path. This allows the team to prioritize activities with important deadlines to meet.
- Plans Resource Needs: The CPM schedule helps the team prioritize activities, allowing for the effective and efficient allocation of resources. For instance, in constructing a high-rise building, the CPM can prioritize activities such as foundation pouring, structural framing, and interior finishing. By identifying the critical path, the project team can allocate resources, such as labor and materials, to these key activities, ensuring that these resources are available to complete critical tasks on time.
- Eases Project Monitoring: The CPM schedule helps determine if activities are on time or late based on the original schedule. It gives planned early and late dates for each activity. By comparing these planned dates with actual dates during the project, you can see if the schedule is ahead or behind your baseline.
- Improves Future Project Planning: Analyzing variance data between actual and planned dates from past construction projects allows construction managers to identify patterns where timelines were either met or exceeded. For example, if a construction project consistently experiences delays in certain phases, construction managers can refine their estimates and forecasts for future projects, leading to more accurate project planning.
- Helps Anticipate and Respond to Delays: Schedulers can identify the critical path to anticipate delays and prevent them from affecting the project's completion date. CPM's visualizations help contractors quickly assess the severity of any timeline issues and decide if they need to request more time or compensation under their contract.
What should you include in a CPM construction schedule?
Critical Path Tracking Template by Kate Eby from Smartsheet
To create an effective CPM construction schedule, you need to include all the necessary elements that will keep the project moving forward smoothly. Here are the elements that you should include in your CPM construction schedule:
- Tasks: A single unit of work within a series of activities that contribute to completing a construction project or deliverable.
- Task Dependencies: Refers to the relationships between different tasks in a construction project, where one task must be completed or initiated before another can be started or completed. The four types of task dependencies are finish-to-start, finish-to-finish, start-to-start, and start-to-finish.
- Earliest Start Date: The earliest possible date that a specific task can begin. This date is usually determined by the project's overall earliest start date.
- Latest Start Date: The latest possible starting date for a task without causing any delays in the project.
- Earliest Finish Date: The earliest possible completion date for an activity in a schedule.
- Latest Finish Date: The latest possible date for completing an activity without affecting the overall project finish date.
- Float: Indicates the amount of time a construction task can be delayed without impacting the project timeline. Tasks with float are not considered critical to the project's schedule.
- Total Float: Refers to the amount of time that construction activity can be delayed without impacting the project's final deadline. It is determined by calculating the difference between the late and early dates of the project and can be computed using specific formulas:
- Total Float = Late Finish Date – Early Finish Date
- Total Float = Late Start Date – Early Start Date
- Crashing: Involves adding more resources to a task to expedite its completion. This may include hiring additional staff or outsourcing the work to external contractors for a fee in order to prevent delays in the project timeline.
- Crash Duration: Refers to a project management technique used to reduce the time needed to complete a task. By adding resources to the project, tasks can be completed in a shorter time frame, ultimately speeding up the construction project's timeline.
- Critical Path: Longest sequence of essential and interdependent tasks required to complete a project. Any delay in completing a task on the critical path will result in a delay in finishing the entire construction project. It’s important to note that not all tasks in a project are part of the critical path.
- Project Milestones: Significant points in a construction project schedule, marking key events like the beginning or completion of project phases and their anticipated completion dates.
6 steps on creating a CPM construction schedule
Many project managers may find it challenging to create a comprehensive and realistic schedule that accurately reflects the project's scope and requirements. Take a look at these steps to create an effective CPM construction schedule.
Step 1: Identify each activity or task in your construction project
Tasks may be listed or sourced from the project's work breakdown structure (WBS). It is important for tasks to be clearly defined and measurable in order to track progress and success.
For instance, you can use CPM to plan a specific part of a project, like improving a building enclosure. You would identify all the tasks between the previous milestone, such as evaluating the building enclosure for repair demands, and then plan and proceed next milestone.
Step 2: Organize the construction task sequences and dependencies
To establish the sequence of activities and their relationships, consider the following for each task:
- Identify the task that precedes the start of another task.
- Determine which tasks can be done simultaneously with the task at hand.
- Establish the tasks that should follow after each specific task.
Step 3: Estimate activity durations
Your team needs to estimate the time each task will take. You can survey members to determine the minimum and maximum time for each task and then average those estimates.
Step 4: Create the critical path network diagram
After identifying all construction activities and their dependencies, the next step is to create a critical path analysis chart, also known as a network diagram. Contractor teams typically use software for this task, but understanding the basics is important. You may want your team to create a simple plan manually or with a critical path template to grasp the concept.
Step 5: Identify the critical path
After completing the critical path network diagram, you can determine the critical path. This includes a set of activities that must be completed on time for the project schedule to stay on track. If there is a delay in any activity on the critical path, it will delay the project's overall completion.
Step 6: Update the critical path as needed throughout the project
As you work on your project, you will see how long each activity actually takes to complete. Update your network diagram with the new information rather than relying on your initial estimates. You may discover a different critical path by continually updating your diagram as more data becomes available. This will help you track your progress more accurately and get a better idea of when your project will be completed.
CPM scheduling for construction: 7 best practices
Many construction managers struggle to implement CPM scheduling effective practices, leading to inefficiencies and setbacks. Here are seven best practices for creating an effective CPM construction scheduling:
Integrate CPM Scheduling and BIM: You can link your CPM schedule to your Building Information Model (BIM) and create 4D simulations to track project progress and identify potential issues. Automating some CPM scheduling tasks, like progress updates and report generation, can save you time and money.
- Let the CPM Schedule Show which Activities Are Most Important: While your team may have their ideas on essential project activities, the CPM schedule generated by software may reveal different priorities. It might show that less prominent activities are actually critical to project completion. It is important for your team to focus on these activities accordingly.
- Organize, Link, and Sequence Every Construction Activity: In a construction project, each task depends on completing a predecessor task. Every task has at least one other task that depends on its completion, known as a successor. Your team must analyze all activities, arrange them correctly, and understand how each task is linked to others.
- Set Realistic Timelines: You cannot rush a construction project by forcing your team to complete tasks out of order. If a construction task is estimated to take 20 days, you cannot expect it to be completed in 10 days with the same resources.
- Recognize the Limitations of Your Resources: Team leaders and members must be aware of resource limitations when estimating the duration of activities. Additional resources can occasionally be added to expedite urgent tasks, but this is not common. Typically, work must be completed using the resources that are currently available.
- Monitor Progress: It's important for your team to check the schedule and work in progress regularly. Are tasks being completed on time? Is it necessary to monitor tasks on the critical path closely?
- Be Prepared to Adjust Your Schedule If Needed: Changes will impact the construction project's activities and deadlines. The team should monitor the schedule continuously and make adjustments as needed.
Master project timing on your construction projects with BD+C
CPM scheduling is a crucial tool in the construction industry, allowing construction managers to plan and track the progress of their projects effectively. With the help of BD+C's expert guidance and insights, you can master project timing and ensure your construction projects are completed on time. Subscribe to our newsletter today and get unlimited access to the best tips and strategies in building, design, and construction to ensure your project's success!
FAQs about CPM construction schedule
While CPM scheduling for construction can help in construction project timing, there are commonly asked questions that construction managers should know for a better understanding of CPM before applying it to their projects. Let’s take a look at them below:
What is the difference between the CPM schedule and the gantt chart?
While Gantt charts offer greater flexibility for project managers to adjust schedules and incorporate new tasks, the CPM is a more structured approach that necessitates redesigning the entire network diagram in case of any alterations to the project plan. A CPM ensures a comprehensive and precise analysis of the project's critical path, making it a superior option for achieving project efficiency and success.
Can a project have two critical paths?
Many projects often have multiple critical paths that require careful management to complete successfully. If progress stalls on any of these paths, even after the primary one is completed, the project could ultimately fail.
What is the disadvantage of CPM?
One disadvantage of using CPM is that it makes it harder to see issues with non-critical tasks, as CPM focuses on or prioritizes critical tasks.