Estimating in Building Construction 8th Edition- PDF for free
Building construction is the determination of the construction cost of a given project. Many items affect and contribute to the cost of a project. Each item must be analyzed, quantified, and priced. Since the estimate is prepared before the actual construction, the construction documents require much research and forethought. An estimator who can visualize a project and accurately determine its cost is one of the most important individuals in a construction company.
For projects constructed under the design-bid-build (DBB) method, contractors must submit competitive estimates. Competition for construction bids is fierce, with multiple firms vying for a single project. To stay in business, contractors must be the lowest qualified bidder on a certain number of projects while maintaining an acceptable profit margin.
This profit margin must provide the general contractor with an acceptable rate of return and compensation for the risks associated with the project. Since estimates are prepared from building shop drawings and project manuals, the estimator’s ability to visualize all of the various phases of a construction project is a critical component of a successful bid.
What is Construction Estimating?
Construction estimating is the process of predicting the cost of a construction project. It involves calculating material costs, labor costs, and overheads. Think of it as making a shopping list before going to a store. You need to know what you want before you can figure out how much you’ll spend.
When builders estimate costs accurately, it ensures they don’t end up in a financial pickle down the road. An accurate estimate helps everyone involved—owners, contractors, and workers—understand the budget and plan accordingly.
Types of Construction Estimates
There are several types of construction estimates, each serving a different purpose. Here are a few key types:
1. Preliminary Estimates
These estimates come early in the project, often before detailed plans are made. They give a rough idea of what the project might cost. Imagine trying to guess how much a meal will cost before you even look at the menu. You have a general idea, but the final price can vary greatly based on your choices.
2. Detailed Estimates
Detailed estimates are more precise. They break down all the costs into specific categories, such as labor, materials, and equipment. This is like making a detailed grocery list, where each item has a price next to it. With this type of estimate, you can see exactly where your money will go.
3. Bid Estimates
When contractors submit bids for a project, they provide bid estimates. This is their formal offer to do the work for a specific price. Think of this as making a formal proposal for a job—showing exactly what you’ll do and how much you’ll charge for it.
The Estimating Process
Estimating isn’t just about crunching numbers; it’s a systematic process. Let’s look at the major steps involved in estimating a construction project.
1. Gathering Information
The first step is to gather all necessary information. This includes project plans, specifications, and site conditions. It’s like gathering ingredients before you start cooking; if you miss something, your dish might not turn out right.
2. Measuring Quantities
Next, you need to measure the quantities of materials and labor required. This might involve going to the site and taking measurements or reviewing blueprints. Accurate measurements are crucial; one wrong measurement can throw off the whole estimate.
3. Pricing
Once all quantities are known, it’s time to assign prices. This involves researching current market rates for materials and labor. Prices can fluctuate, much like the stock market, so it’s important to get the latest information.
4. Compiling the Estimate
Now it’s time to put everything together. The quantities, prices, and any additional costs (like permits and overhead) will be compiled into a final estimate. This is like assembling the final puzzle, where every piece has a place.
5. Reviewing and Finalizing
Before sending out estimates, it’s vital to review them for accuracy. Double-checking prevents costly mistakes. Think of this step as proofreading a paper before turning it in—every detail matters.
Importance of Accurate Estimating
Accurate estimates are crucial for several reasons:
- Budget Management: They help keep projects within budget.
- Time Efficiency: Proper estimates save time by preventing unexpected delays.
- Trust Building: Accurate estimates build trust between contractors and clients, ensuring everyone’s on the same page.
Common Challenges in Estimating
Despite its importance, estimating can be challenging. Some common hurdles include:
- Changing Prices: Material costs can rise unexpectedly, affecting the budget.
- Incomplete Information: Missing details can lead to inaccurate estimates.
- Time Constraints: Tight deadlines may rush the estimating process, increasing errors.
Estimating in building construction may seem daunting, but with the right approach, it can be mastered. It requires careful planning, keen attention to detail, and an understanding of the ever-changing construction landscape. Building a strong foundation in estimating not only leads to successful projects but also fosters positive relationships within the construction community. So, whether you’re a contractor or a homeowner, grasping the nuances of estimating can make all the difference in turning your building dreams into reality.
About the Book
The Eighth Edition continues to build on the solid foundation of the previous edition. Estimators need to understand the theory behind quantification before computerized estimating can be performed. This fundamental principle has been passed down from Mr. D’Agostino to the current author, and it is essential for estimators to fully understand.
In this book, the methodology and structure of estimating are explained with extensive examples and exercises. Estimating is an art that relies heavily on the judgment of the estimator. Therefore, readers are encouraged to complete the examples and apply the skills learned in this book. Since estimates are used throughout the project, assumptions and methodologies should be documented and organized.
Estimating problems using the Building Information Model for wooden office buildings (included on the accompanying website) is featured in many of the chapter problem sets.
The intent of this revision is to expand the totalization material covered in this document and to bring other material in line with current industry practice.
