Construction estimating textbooks pdf are available in many different formats. You can read them on your computer, or print them out for reading. You can also download them as epub or mobi files.
This book combines sound coverage of principles with step-by-step procedures to help students learn concepts more easily. It is ideal for construction, architecture, and engineering students.
Basics of Estimating
Getting accurate estimates requires solid data and a clear understanding of the estimating process. A solid estimate is not only important for planning, but it also helps ensure that projects are completed on time and within budget. Estimators must be able to recognize potential errors in their work and avoid them, but this is not an easy task. If a mistake is made, it can cause serious consequences for the project and its stakeholders.
One of the most common mistakes is overestimating. This happens when the estimator doesn’t take into account hidden costs or unforeseeable changes in the construction process. This can lead to budget overruns and delay the project’s completion date. To avoid this, it’s important for the contractor to develop a method for evaluating and correcting errors in the estimate.
A good way to do this is by using a quantity takeoff software program. This tool provides a detailed list of materials and labor costs for each component of the job. It also includes suggested crew sizes and equipment rates. Alternatively, a construction cost data reference can provide you with estimated prices for each material. This resource can help you avoid errors in the estimate by comparing actual project costs with the estimated costs provided in the data reference. This will help you improve your estimating accuracy and reduce the number of revisions that you have to make.
A good construction cost estimate is an important tool for any project manager. Although estimating the costs of a project with absolute precision is impossible, a skilled estimator will account for as many variables as possible to create an accurate estimate. Failing to prepare an estimate with sufficient accuracy can have disastrous results, as in the case of Marble Hill nuclear power plant, which was abandoned after seven years of construction and $2.5 billion in cost overruns.
Cost estimators use a number of different tools to prepare estimates, including computer programs and spreadsheets, spreadsheet templates, specialized software applications, and physical inspections of construction sites. They also rely on historical cost data from past projects and material prices, which can vary widely depending on market conditions.
For a project that is being bid on, estimators prepare a document called a bill of quantities, or an itemized list of work and materials required for the construction of the project. This list is made available to all contractors who wish to bid on the project and may be used for the purposes of comparing and selecting the most competitive bids.
A typical bill of quantities is compiled using a four-step process: calculating labor hours, labor rates, and equipment costs; performing a quantity take-off of the project; abstracting and ordering items by size, weight, and material type; and making deductions for items that are not needed or will not be installed. Some estimating textbooks offer a template to help students understand the process.
Variance analysis is the practice of comparing predicted costs or outcomes with actual numbers and results. This comparison allows businesses to track trends, determine cause and develop corrective action plans. Variances can be measured monthly, quarterly or yearly and are typically presented as a percentage of budgeted totals. In general, a negative variance is considered unfavorable while a positive variance is favorable.
Performing an effective variance analysis requires high-quality data, which isn’t always easy to come by. The data used for variance analysis should be verified and based on operational information that is trusted by the company’s stakeholders. It also needs to be easily accessible by the people who will use it for decision making and planning.
The most common types of variance analysis include material variances, labor variances and overhead variances. The calculation for each type is relatively the same: subtracting the budgeted amount from the actual amount. However, each type of variance has a different focus: direct material variances analyze the cost of purchased materials compared to budgeted amounts; labor rate variances examine the cost of direct labor versus budgeted labor hours; and overhead variances measure fixed overhead expenses incurred compared to budgeted totals.