A build schedule is one of the main components in determining project cost. The length of time it will take a contractor to build the project once all the initial construction contracts have been awarded has a direct affect on the cost of construction.
It will be the responsibility of the project estimator to determine the length of time needed for direct overhead items like supervisory personnel, trailer and equipment rental, toilet facilities, etc. in addition to coordinating the time and sequence of activities by contracted trades.
With a fairly detailed scope of work provided by an owner to a contractor, the estimator is better equipped to calculate the length of time needed to complete the work, to plan the sequence of the work trades and when materials should be ordered and then delivered to the project site for installation within that allotted time frame.
A Build Schedule Breaks Down Into Multiple Areas
LIST OF ACTIVITIES
The first area is listing all the activities of work required for completion of a project. Each portion of the work is them broken down even further.
For example, a schedule may include concrete as work item however, this description by itself is too broad to accurately estimate either time or cost.
An item like concrete may be further detailed to include footings, foundation, slab on grade, reinforcing steel, walls, forms, concrete testing, finishing or curing.
Each item has a specific time element associated with completing it and many of the items may not be completed until a specific activity is completed before it. This called a predecessor activity.
Another example might be drywall. This again is too broad in schedule terms because there are predecessor activities associated with the actual hanging of drywall like framing, mechanical or electrical rough-in, and insulation. Each activity will have its own time allotment and contribution to the overall length of construction.
This is not to say an owner needs to provide that level of detail in their scope of work description to a contractor but the more detail the better the accuracy of the project cost.
ORDERING MATERIALS IN A BUILD SCHEDULE
The second area in a build schedule is the ordering of materials. While many work materials are available either in a trade contractor’s stock or from a supply house, there are many items which are long lead and may require weeks or months to get.
An example of long lead items might be air conditioning equipment or custom-made windows that need to be field measured before they can be fabricated.
Custom finishes like furniture fabrics or special patterned carpeting are also examples of long lead items where a contractor must include, within the build schedule, the appropriate time frame to get the material on-site so it does not impact other scheduled activities.
DELIVERY OF MATERIALS IN A BUILD SCHEDULE
In a perfect world, everything would show up when it is supposed to and that’s not the case. Some materials may be ordered for a morning activity and then for whatever reasons, it doesn’t arrive. This impacts not only that activity but any successor activities that follow that work.
The contractor would likely include “contingency” costs in his estimate to cover these situations where he may be required to accelerate the work of a successor trade to maintain the project build schedule.
This is often a point of contention between owners and contractors as to who owns the contingency. Owners prefer to dictate how contingency funds are spent with any unspent funds credited to them at the end of the project whereas contractors want to be able to own and use the contingency as they see fit.
SCHEDULING ACCURATE ACTIVITY TIME SLOTS
A construction build schedule that doesn’t reflect accurate activity time slot makes for an inaccurate schedule that can end up costing either the contractor or an owner money. Related activities need to be appropriately linked in a build schedule so the allotted window of time is accurate.
Using the concrete example again, concrete cannot be poured until the reinforcing steel or mesh is installed. The reinforcing steel or mesh isn’t installed until the concrete forms are in place and none of it can be complete until all the material is delivered so the work can progress in sequence.
LABOR AND MATERIAL CALCULATIONS IN A BUILD SCHEDULE
When all the work activities are identified, then the task of assigning costs to how many workers and equipment are needed to complete each activity is next.
It’s important for the contractor to ensure he does not have the same equipment, like a backhoe, scheduled for two different activities at the same time since this will impact the progress of the work and could result in project delays or acceleration costs.
The comprehensive build schedule of activities are generally organized into the required flow for categorized scopes of work.
This then makes it easier to determine fairly accurate project estimated costs, can help determine how best to utilize supervisory personnel for orderly management of the project and all in the interest of timely and profitable project completion.
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