An estimate of construction work is a determination of the possible construction cost of any project. Many items affect and contribute to the cost of the project; each item must be analyzed, quantified and priced. Estimates are prepared before the actual construction, so much research and thought must be put into the construction documents.
An estimator who can visualize the project and accurately determine its cost will be one of the most important persons in any construction company.
For projects built with a Design-bid-build (DBB) delivery system, the contractor is required to submit a competitive cost estimate for the project. Competition for construction tenders is fierce, with multiple companies vying for a single project. To stay in business, the contractor must be the lowest qualified bidder for a specific number of projects while maintaining an acceptable profit margin.
This profit margin should provide the general contractor with an acceptable rate of return and compensation for the risks associated with the project. Estimates are made from building work drawings and project manuals, so the ability of estimates to visualize all of the different phases of a construction project will be a major component of a successful bid.
The seventh edition continues to build on the strong foundations of previous editions. The need for estimators to understand the theory behind quantification is important and must be fully understood before performing computerized estimates.
This under lying premise is one of the guiding principles that began with D. Agostino and continues to the current author. This edition uses extensive examples and exercises in the organization of estimates to demonstrate methodology. Estimation is an art that largely depends on the judgment of the person performing the take-off. The technique of man estimation can only be developed with practice; therefore, readers are encouraged to work example problems and apply the techniques taught in this book. Estimates are used throughout the project, so the assumed assumptions and methodologies must be documented and organized so that subsequent users can access this knowledge.