Construction projects require careful planning and cost management to be completed on time and within budget. One of the most important factors in construction budgeting is developing accurate estimates of the time required to complete the project. Understanding how to estimate construction time is crucial for creating realistic project schedules and budgets.
Understanding the Basics of Construction Time Estimation
Estimating the time duration of construction activities is a fundamental part of the project planning process. The time estimate provides the basis for scheduling project activities, calculating costs, planning resource needs, and meeting project deadlines.
Construction time estimation involves analyzing the scope of work and calculating the time required to complete each activity from start to finish. Activities include things like mobilization, excavation, foundation work, structural framing, mechanical and electrical work, finish work, inspections, and demobilization.
The total project duration is calculated by sequencing all the activities and determining the critical path – the sequence of interdependent activities that must be completed on schedule for the project to finish on time. Even small errors in estimating individual activity durations can throw off the critical path and planned project completion date.
Importance of Accurate Time Estimation in Construction
For contractors, accurate time estimation is critical for several reasons:
- Creating realistic schedules and budgets
- Bidding competitively on projects
- Managing labor, equipment, and materials efficiently
- Avoiding cost overruns due to delays
- Delivering projects on time and within budget
- Maintaining a positive cash flow
- Meeting contractual obligations and avoiding penalties
Underestimating time requirements leads to rushed, unsafe work, cost overruns, and negative profit margins. Overestimating is also problematic if it results in an uncompetitive bid or unnecessary expenses.
Precision in estimating construction time requirements separates profitable projects from problem projects.
Key Factors in Estimating Construction Time
Construction projects are complex, with many variables that must be considered when estimating duration:
Scope of Work
The specifications, drawings, and project requirements shape the required tasks. Unique project parameters like site conditions, building design, and regulations will impact the time needed.
Resources
The types of labor, equipment, and materials allocated to each activity affect productivity. Resource planning must consider whether resources are shared across activities or dedicated.
Production Rates
How many work units can be completed per unit of time? Production rates are influenced by factors like workforce experience, site conditions, weather, and more.
Efficiencies
Time estimates account for productivity factors like fatigue, learning curve, distraction, and downtime.
In summary, an accurate time estimate requires thoroughly evaluating the scope, sequence, resources, expected production rates, and efficiencies of the project.
Different Techniques of Time Estimation in Construction
Several techniques are used to estimate the duration of construction:
Experience-Based Estimating
Relies on knowledge from past projects of similar size, scope, and complexity to predict the time required.
Units/Quantities Estimating
The quantity of work units is calculated and multiplied by the expected production rate per unit to determine duration.
Computer-Based Estimating
Uses estimation software to analyze costs, model sequences, run simulations, and determine durations.
Reference Estimating
Uses historical data from reference books, cost databases, or cost estimation software to estimate based on building type and size.
Vendor Quotes
Duration information received directly from subcontractors and equipment/material suppliers based on project parameters.
Each method has pros and cons. Using a combination helps overcome the limitations of any single technique. Experience and data-based estimates provide a starting point. Vendor quotes add detail on material lead times and crew productivity. The software provides data analysis and scenario testing.
Features of Construction Project Management Software Affecting Time Estimation
In addition to dedicated scheduling software, many construction project management software platforms now also provide tools to improve time estimation, including:
- Digital time cards – Track accurate dates and hours worked on each task to collect real-world productivity data.
- Equipment utilization – Log equipment use hours to refine estimates of production rates.
- Project templates – Reference typical timelines from past projects to estimate new ones.
- Photos and document markup – Attach visuals to illustrate site conditions and specifications to improve estimate accuracy.
- Mobilization planning – Factor in time needed for submitting permits, renting equipment, hiring subs, and staging the site.
- Multilingual support – Communicate time estimates effectively for multicultural workforces.
Construction management platforms provide the tools contractors need to develop, manage, and refine project time estimates throughout the job.
The Benefit of Using Construction Time Tracking Software for Time Estimation
Purpose-built time tracking software provides invaluable data for honing the accuracy of construction time estimates. Features include:
- Timestamped activity start and stop times
- GPS location data confirming where and when work is occurring
- Real-time time tracking rather than post-project estimations
- Time cost code assignment for detailed reporting by task
- Overtime alerts to identify schedule overages
- Supervisor sign-offs to confirm reported activity durations
- Required break tracking to analyze lost time
With reliable time-tracking data from past projects, estimators can derive productive labor rates and typical activity durations across various conditions to improve future estimates. Time tracking helps move time estimates from guesses to precise projections based on the company’s actual performance.
Common Pitfalls in Construction Time Estimation and How to Avoid Them
While estimating construction time is not an exact science, being aware of common missteps can help avoid major scheduling mistakes:
Not Allowing Time for Mobilization/Demobilization
Don’t overlook pre-project planning, permitting, staging/storage, and post-project closeout and cleanup when estimating the schedule.
Optimal Conditions Assumption
Be realistic about probable weather delays, site conditions, resource availability, and subcontractor coordination when estimating activity duration.
Ignoring Testing, Inspections, and Approvals
Ensure the estimate includes time for mandatory inspections, testing protocols, and document approvals between tasks.
Unforeseen Complexity
Build in buffers for discovering unseen conditions or complexity once work begins that may slow the pace.
Lack of Historical Data
Making estimates without parallels to past projects leaves you guessing instead of calculating durations.
Mismatched Resources to Task
The pace of work slows down when the right types of equipment and crew sizes aren’t specified during estimation.
Failure to Update
As changes happen, failure to adjust the time estimates means the schedule no longer reflects reality.
With careful evaluation of past productivity, factoring in probable delays, padding for contingencies, and continuously tracking progress – contractors can minimize time estimating errors.
Practical Tips for Accurate Time Estimation
Follow these best practices for optimal construction time estimating:
- Clearly define project requirements and scopes of work for each activity upfront
- Break down activities into manageable components that can be accurately estimated
- Consult historical data on task durations from past projects
- Discuss assumptions and uncertainties to build in buffers at each phase
- Get vendor and subcontractor input on projected time requirements
- Assign resources to each task and assess capacity constraints
- Build a master schedule, then optimize the sequence to shorten the overall duration
- Always estimate conservatively, then monitor actuals to reduce overruns
- Provide frequent schedule updates as more data comes in on task durations
- Leverage scheduling software to quickly model and compare time scenarios
With thoughtful planning using proven estimating techniques and tools, contractors can meet project deadlines and maintain happy clients and profitability.
How ExakTime Can Help Improve Construction Time Management
ExakTime is purpose-built, fully-featured time-tracking software for contractors who are serious about accuracy in time and cost management.
Robust reporting on overtime, schedule variances, and activity costs quickly highlight problems for swift corrective action. Manage labor, equipment, and materials precisely to prevent delay.
Streamlining Time Tracking for Field and Office
ExakTime makes time tracking extremely simple for crews in the field. Employees can clock in and out via the mobile app with one touch using geofenced photo ID capture to confirm their location on site. GPS timestamps automatically record when and where work is happening without relying on memory at the end of the day.
Managers have access to real-time visibility into the whole workforce with interactive maps showing who is clocked in across all jobs. ExakTime integrates with over 100 different payroll systems, allowing you to skip manual data entry and have accurate information flow directly each pay period.
Purpose-Built for the Way Construction Works
Unlike generic software, ExakTime was designed from the ground up with the needs of construction firms in mind. You can assign specific cost codes and equipment tags so project data rolls up in real-time. Custom alerts notify supervisors when crews approach overtime or when rest breaks are due.
Specialized training and support help ExakTime users adopt and utilize the software to its full potential.
With ExakTime, every construction management process, from bidding to scheduling, cost management, payroll, and compliance, becomes simpler and more accurate.
Estimating construction time is essential to delivering projects on schedule and on budget. By carefully evaluating project requirements, identifying key activities, analyzing historical data, validating with vendors, building detailed schedules, and continuously tracking progress – contractors can develop and maintain accurate time estimates. Combined with purpose-built time-tracking tools, estimators can move from guesswork to precision projections. Now, put these time-estimating best practices into play on your next construction job.
