How to estimate a construction time period
Hard working construction worker at a construction scene. image by Andy Dean from Fotolia.com
Whether you're involved in a home remodelling project or a large commercial job, construction scheduling is an important tool for keeping the project on track. A schedule keeps builders, designers, contractors and project owners accountable and establishes a set of guidelines that help the job progress.
To develop a construction schedule, you'll first need to estimate the time required for various activities and then determine how these activities relate to one another.
List all activities required to complete the project. For example, if you're remodelling a bathroom, your activities include demolition, plumbing and electrical rough-ins, fixture installation, ceilings, flooring, painting and trim. Larger projects may require hundreds of activities.
Add administrative tasks and material lead times. Administrative tasks may include signing the contract, selecting materials or approving product. Include lead times for all items that are not readily available, including custom finishes, light fixtures and equipment.
- Whether you're involved in a home remodelling project or a large commercial job, construction scheduling is an important tool for keeping the project on track.
- To develop a construction schedule, you'll first need to estimate the time required for various activities and then determine how these activities relate to one another.
Link these activities in terms of relationships. For example, ceiling work cannot begin until demolition is complete, so the start of ceiling work must be linked to the last day of demolition. If you are using a scheduling program like MS Project, these activities are easy to link. Small jobs may be simple to link together using a pen and paper. Don't forget to link things like material approvals and lead times to the start of the applicable activity. If doors will take eight weeks to ship after approvals, door installation cannot begin until at least eight weeks after the project begins.
Estimate durations for each activity, and determine how many work days are required. You may need to consult your subcontractors or other project team members for help with this task. For example, if one ceramic tile installer can lay 100 square feet per day and you have 1,000 square feet for your two-man crew to complete, they will require five work days to complete the tiling. Repeat this process for all activities on your list. List these durations next to each activity.
- Link these activities in terms of relationships.
- If doors will take eight weeks to ship after approvals, door installation cannot begin until at least eight weeks after the project begins.
Present your schedule to suppliers and contractors and ask for feedback. Confirm material lead times and activity durations. Ask contractors how long certain activities will take; if their estimates differ from yours, ask for a breakdown in terms of labour and productivity if the duration seems too long. Adjust the schedule as needed to reflect any feedback received.
Examine your list of activities, durations and how each activity relates to the others. Using this list, you can estimate your overall construction time period from start to finish, as well as a projected completion date.
- If you do not have access to construction scheduling software, stick with a general scheduling program like MS Project. To perform this task by hand, create a bar chart, with the bars representing specific time durations. For linked activities, one bar will have to start after the first has ended to illustrate the relationship between these activities.
Emily Beach works in the commercial construction industry in Maryland. She received her LEED accreditation from the U.S. Green Building Council in 2008 and is in the process of working towards an Architectural Hardware Consultant certification from the Door and Hardware Institute. She received a bachelor's degree in economics and management from Goucher College in Towson, Maryland.