Uncover the integral role of variables in project estimation and the importance of understanding the work breakdown structure (WBS) in organizing a construction project. This article also highlights the differences between general conditions and general requirements, the significance of markup, and the need for familiarity with different measurement systems.
Key Insights
- The article emphasizes that variables, defined as units that change from project to project, are important to understand as these are determined in a quantity takeoff. They could refer to any specific item in a project, such as the wall height or length.
- The Work Breakdown Structure (WBS) is a crucial aspect of project organization. It divides the total project scope into manageable elements and can make distinctions such as different project phases or on-site and off-site work.
- Recognizing the difference between general conditions and general requirements is vital. General conditions refer to the cost of managing a construction project, while general requirements pertain to specific owner requirements within a project which could potentially increase the cost.
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Let's talk a little bit about variables—these occur everywhere, whether you realize it or not. Variables are values of a specific item in a formula that may change. A classic example is a variable for wall height.
Each project is going to be different. One of the variables for height could be 10 feet, or it could be 11 or 12 feet. The other variable for the length of a wall could be anything.
It could be 2 feet, it could be 2,000 feet. So variables are defined as units that will change from project to project or from each condition to each condition within the same job. The variables are defined within a quantity takeoff.
Not only in the takeoff, but in the description of the item that you're doing your takeoff on. Work Breakdown Structure—very important—and you'll find yourself working with the Work Breakdown Structure without even realizing it. Work Breakdown Structures, also referred to as WBS codes, are a deliverable or project-oriented grouping of project work elements which organize and subdivide the total work scope of a project.
A classic example is Phase 1 and Phase 2. That's part of a Work Breakdown Structure. In other words, you want to know how many objects, how many items, or how many units of measure for any one item are available for Phase 1 or that should be required for Phase 1. The same would go for Phase 2. A Work Breakdown Structure can also represent something as simple as all of the site work versus all of the off-site work that might be out in the street where you tie into the existing utilities. It could also be separate from a parking structure or from the building itself that we're working on.
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Work Breakdown Structures must be identified and understood before performing your takeoff, and before building your estimate. General Conditions: The costs required to manage or operate a construction project.
So that means if you're a general contractor, it requires a certain cost and expense to operate the entire project itself. You may actually have a job site trailer. You can have a superintendent.
You might have a Project Engineer on site or a couple of Laborers. These are considered the General Conditions. These are the costs required to run the project, even before a superintendent arrives on site to perform any work.
General Requirements: This is a little different. They sound very similar, and sometimes they are conflated.
They're mixed together. But General Requirements are typically owner requirements for construction, and they're accounted for through the general contractor. The general contractor will use General Conditions.
Now the General Requirements are part of the project, but they may be above and beyond the cost of the project. In other words, you could have an owner say, “You know what? We need a bigger trailer to have our weekly meetings in where we want to participate with our Architect and engineer.” That becomes a General Requirement, and the general contractor may then charge extra for it.
On-site means that the work is taking place within the construction project itself. You could have a number of people who are working on the project but are not present on-site. They could be working out of the main office.
But on-site means that if you've got a superintendent on site, it's taking place at the construction project or very close by. It could be in the parking lot, out of a job site trailer. It is all considered on-site.
Markup—very important. That's why we're in business.
Once we determine what the total cost of the estimate may be, we then apply markup to it, and we're going to go into great detail on that later. When you hear the term markup, it refers to the profit or added cost above all actual hard costs of the project. There are a couple of measurement types that we need to address.
Typically, the imperial measurement system is used in the United States. This includes inches, feet, cubic yards, miles—whatever it may be. Then there's the metric system, which we, as estimators, encounter from time to time.
The metric measurement system is used almost universally throughout the world—with the exception of two countries, the United States being one of them. The metric measurement system is important to understand—how it functions and how to convert values. But it does not typically apply to most projects that we work on.
And from my own opinion, the metric measurement system is a whole lot easier to utilize. If we ever make that conversion, it’s just so much simpler because it defines everything in quantities of 10,100,1,000, and so on.
