Frequently asked questions

Quantity Take Off Methods

Quantity take-off methods are a means for estimating the cost of each aspect of a project. A project consists of many activities and materials all of which are accounted for as items of a project. For example, a project may involve the construction of a retaining wall. There are many activities and materials associated to complete this. Some include excavation, formwork, concrete for the wall, reinforcing steel etc. When contract drawings and specifications are developed, all of these items must be identified. All items also must include a quantity associated it's them to indicate the amount or extent of work for the item. These quantities must be defined by a particular unit of measure which must be appropriate for the action or material. Taking excavation as an example of an item, there must be an amount of excavation associated with it. Since excavation involves removing a volume of material, the most appropriate unit is cubic yard or cubic feet. To estimate the cost of the project, each item has a price per unit associated with it. This price is determined by previous similar work and taking into account the specifics of the particular project. Below is an example of the breakdown of some items associated with an example retaining wall project:

Cost Estimating

Project Schedules

Project schedules must be set and maintained to ensure it remains on time and on budget. To determine a project schedule, all tasks must be identified and the length of time (durations) for each task must be estimated. These tasks can then be sequenced by determining what the appropriate order of tasks are. Some tasks must be completed before others can begin. These tasks are defined as predecessors. See the example chart below indicating identified tasks, durations, and predecessors: This information can then be visualized by producing and activity diagram. First begin by drawing tasks. Start with A: Then determine which tasks have A as a predecessor. Draw these tasks as well with arrows indicating these tasks are connected: Continue in the same manor with each task. The final chart is as follows: Then you can determine the critical path of the project. The critical path is defined as the sequence of tasks which would yield the shortest amount of time to complete the project. If the duration of any task on the critical path is changed, the duration of the entire project will change. In the example above you can determine the critical path by identifying all paths and the critical one is the longest sum of duration. Therefore the possible paths are A-B-D, A-B-E, and A-C-E which have total durations of 6, 7, and 6. Therefore the critical path is A-B-E. A change in duration of non-critical tasks will only change the project duration if the change creates a longer path than the existing critical one.

Activity Identification and Sequencing

The appropriate steps in the proper sequence need to be identified to complete a project. This involves understanding all the tasks involved in a specific project type and providing a timeline of events to properly facilitate the successful completion of the project. There are many types of projects and the specifics can vary. For the purposes of the PE Exam, it is important to have a general knowledge of common construction tasks and sequences. Below are some examples of design and construction tasks divided by when they occur in certain project phases:

Pre-Design/Design/Project Award

  • Owner initiates project
  • Owner hires Architect/Engineer or uses In-House Architect/Engineer
  • Contract documents and specifications are developed
  • Contractors bid on the project
  • Project is awarded


  • Contractor submittals are reviewed and approved
  • Sub-Contractors hired
  • Site survey, staking, and layout
  • Procurement of materials


  • Traffic Control, water handling, etc. installed if necessary
  • Crane set up and positioning
  • Temporary earth retaining systems installed if necessary
  • Excavation
  • Formwork or Erection
  • Testing of materials
  • Installation of rebar
  • Pouring of concrete
  • Concrete curing
  • Backfill


  • Semi Final/Final Inspections
  • Open road to traffic
  • Punch-Lists
  • As-Built drawings

  • Black Twitter Icon
  • Black Facebook Icon