Many people dream of constructing their own home rather than buying a ready-to-move one. They want to integrate their personal touch into their home’s design and construction. But the common questions that arise here are: how much time is required to construct a house, and how to complete a construction project on time? Hence, Gharpedia provides a detailed guide on how to estimate construction time for your home and how to schedule a construction project.
So, let’s start by knowing what the construction project schedule is.
What is a Construction Project Schedule?
A project schedule is the sequence of activities on a timeline. For example, if you are constructing your house, and you need to determine how much time is required to construct a house, what you need to do is estimate the time for different activities like designing, foundation work, slab work, finishing work, interior, etc. The total time for each activity gives the construction completion time.
This is the simplest method for making a project schedule; however, it needs a proper methodology for preparation. A construction project schedule helps to calculate an accurate project completion date and the resource requirements for the work.
How to Make a Construction Project Schedule?
To prepare a project schedule, a project manager prepares a work plan that covers the scope and construction methodology. Both planning and scheduling go hand in hand. The schedule arranges the planning on the timeline and associates it with the resources required for the project. To simplify, project planning determines what and how, while project scheduling determines when and who.
There are two methods for preparing a project schedule: forward-loaded and back-loaded. In the forward-loaded method, you fix a start date as a reference and add the duration of activities to determine the completion date. However, in the back-loaded schedule, you back-calculate from the completion date.
Before further elaborating on the concepts of project schedules, let’s understand the advantages of a construction project schedule.
Advantages of Construction Project Schedule
A master construction project schedule may serve many purposes. The output of a schedule depends on the data associated with the activities.
Saves Cost
If you don’t plan a completion date or don’t make a detailed schedule, the project cost may shoot up, impacting your interest cost, cost of overheads, house rent etc. This can bring along a host of other problems. Utilizing Crewcost accounting software can streamline the tracking of labor expenses within the project schedule, aiding in accurate cost estimation and budget management.
Completion Date and Expected Completion Date
A project schedule determines the completion date of the project. In addition, it calculates the expected project completion date based on the project’s progress.
Target Setting
It is a guide for the construction team in setting work targets.
Progress Monitoring
It measures the project’s progress against the set targets and internal milestones.
Control and Mitigation
If progress lags behind the target, you can design and implement control and mitigation methods.
Resource Requirement
The schedule generates the resource histogram. It is a statistical tool that graphically shows the resource requirements like materials, labour, finance, machinery, etc. over the project timeline.
Cash Flow Requirement
A schedule determines the cash required to run and complete the project. Resource working rate is the input for cash flow requirements. This feature also tracks planned versus actual spending. It indicates the project’s progress against the planned progress.
How To Estimate Construction Time: Steps for Making a Project Schedule
A project schedule prepared as per the standard methodology has a higher success rate. A schedule covering all the aspects of the project ensures the project is on track.
Now, let’s learn how to schedule a construction project:
01. Scope and Work Breakdown Structure
Scope
The project scope is a statement of the work packages required to complete the project. Further, the project scope holds the answer to: What needs to be done in the project? Each work package covers deliverables, tasks, constraints, budget, and resources. Furthermore, a scope outlines the project boundary and defines how it affects stakeholders.
Assume you are building a 1000-square-feet single-storey house. If the design and details are final, all legal permissions are on hand, then the following works are to be done.
Work Breakdown Structure
A work breakdown structure (WBS) is a hierarchical decomposition of the work scope. To prepare a WBS, identify the project deliverables. The breakdown of activities will depend on and vary based on the resources required for work and its methodology, i.e, material, labour, plant, machinery, tools, etc. Each deliverable is a milestone in the construction project schedule. To cut a long story short, a WBS forms the skeleton for the project schedule.
Now, let us prepare a project work breakdown structure based on the above information and the layout.
02. Duration Estimation (How Long Every Single Task Takes)
The estimation of the duration of activities in construction projects is possible using either historical data or expert judgment. Both methods are popular in the construction industry and have their pros and cons. However, it is important to use historical data with care, as each project is unique and has different attributes. Similarly, expert judgment is expert opinion-based and can vary due to differences in their exposure, experience, analytical ability, etc.
To determine the duration, we need to define the activities for each WBS element and their respective durations.
For Structural Works-
For Finishing Works–
03. Order of Works (Sequencing)
Now that we have determined the duration for each activity, we can interlink them to calculate the total required construction time for a house.
To explain the sequencing concept, consider activities A and B. Activity B follows Activity A. Thus, Activity A is the predecessor to Activity B. On the same pattern, Activity B is the successor to Activity A.
Any of the four methods mentioned below can link the two activities to each other:
- Finish to Start (FS)
- Finish to Finish (FF)
- Start to Start (SS)
- Start to Finish (SF)
Finish to Start (FS)
A finish to start a relationship is the most logical relationship. Activity B starts after Activity A finishes. There is no overlap in activities. As per the standards, a minimum of 90% of the activities should have an FS relationship.
Finish to Finish (FF)
A finish-to-finish relation links two activities by their completion dates. The activities overlap and finish at the same time.
Start to Start (SS)
Start-to-start relationship links two activities starting at the same time. The activities overlap each other, i.e, they take place simultaneously.
Start to Finish (SF)
A start-to-finish relation is the least used relation. It represents that the successor activity finishes before the beginning of its predecessor. Replace the SF with FS relation by changing the activity sequence.
Lead and Lag
All the activities do not begin at the conclusion of their predecessor activity. Hence, they are offset using lead or lag. A lag is the difference between the end of a predecessor activity and the start of its successor. For example, backfilling activity is to start after three days of foundation casting completion. The lead is 3 days. The representation is +3 days.
A lag is a negative lead. To elaborate on the lag, assume shuttering work for the foundation must start two days before the end of the foundation reinforcement work. The lag is two days. The representation is two days.
The standards say that leading in more than 5% of activities is not a good practice. Moreover, avoid the lag, as it defies logic.
Now, finalising the schedule with relations and lead with a start date, say, January 1 of any year.
This is tentative and for explanation only. It does not include all items, nor are the timelines or quantities 100% accurate
WBS and Activities Duration in days Relation Start Finish
04. Finalising the Schedule with the Contractor (Setting The Baseline)
Now, the activities get sequenced with relations and leads. The project schedule is ready. The house owner and the contractor sit together to finalise the project schedule. Both parties agree on the project schedule and promise to follow it. Now, fix the activity dates and monitor the progress as per the agreed schedule.
To conclude, the schedule agreed upon between the stakeholders is known as a baseline schedule. The activity start date and finish date for a baseline schedule are known as baseline start and baseline finish, respectively.
Every project has a minimum of one baseline schedule. There is no upper limit to the number of baselines. Moreover, at any instance, the progress gets monitored as per the latest baseline schedule.
05. Monitoring and Controlling (Planned vs Actual)
Plan the daily, weekly, and monthly targets as per the baseline schedule and manage resources accordingly. Monitor and report the progress as per the targets.
Some activities directly affect the completion date of the project. For example, if the plinth beam casting gets delayed by 2 days, the whole project will be delayed by 2 days. Such activities are critical activities. To identify a critical activity, change its finish date by X number of days. If the project’s finish date changes by X number of days, it is a critical activity.
Similarly, MEP work that should end on March 18 may be delayed until March 31 without affecting the project end date. Therefore, it is a non-critical activity, and it has a float of 13 days. The critical activity will determine the price of the project.
Steps To Reduce Construction Time for a House
Some of the proven steps that reduce the construction time for a house are:
- Activity crashing is a method of using extra resources to finish the work earlier than expected.
- Overlapping the work is a smart way to reduce the project’s duration. In the above example, starting putty work along with plaster reduces the overall project duration.
- Improve the resource productivity more than the planned value. It reduces the duration of the project.
- Reduce the lag between critical activities.
How to Use a Construction Project Schedule for Maximum Benefit?
To maximise the usability of a project schedule, implement these techniques.
Use the 100% Rule for WBS: A WBS should cover the complete scope. Therefore, all the child activities of a WBS should add up to 100% of the parent activity.
Discrete Nature of the Activity: Every activity defined in any WBS should be self-sufficient. Monitoring and tracking should be easier.
Critical Path: Identify and give special care to critical activities. Always ensure enough resources for the critical activities.
Float: The float is the duration by which an activity may be delayed without delaying the project. Critical activities have zero floats. Keep an eye on the activities that have a lower float. The negligence might make an activity critical and delay the project.
Conclusion
We hope that you are now aware of how to estimate construction time. However, remember that the construction project schedule cannot be prepared by a layman. You need a project manager or an experienced Architect or engineer to do that. An experienced and knowledgeable engineer will prepare a realistic and efficient schedule. Experts will not only tell you how much time is required to construct a house, but they will also help you arrange all the resources. Once the quantity of resources is known, their rightful management will help you complete the project on time, saving you money, and energy. The timely completion will bring lots of happiness and joy to you and your family.
Author Bio
Shazeb Ali –
