construction cost estimate structuring

Construction Cost Estimate – Classification Systems

(Last Updated On: February 23, 2018)

An essential component of any cost estimating approach is the use of a standard framework for classifying and managing construction information. The framework chosen should accommodate cost data needs throughout the project life cycle and respond to the viewpoint and needs of the various users. If a firm does not use a standard construction information framework for estimating its projects, inconsistencies will occur in estimates between projects and between stages of each project. Confusion and ultimately loss of control will result.

Architect’s Essentials of Cost Management

Employment of a standard framework for construction information addresses the following basic needs:

  • Consistency of work products over time and from project to project
  • A frame of reference for collecting and managing information and eventually for evaluating the experience gained
  • A checklist to aid both management and technical decision making clear communication between all disciplines
  • A basis for ongoing training of personnel
  • An efficient basis for automation

The most common data standard in use in the construction industry today is MasterFormat, a system of numbers and titles for organizing construction information into a standard sequence. This sequence is subdivided into 16 divisions organized by major products and trades associated with construction and then into four levels of detail. Level one comprises major groupings such as bidding requirements, contracting requirements, and the 16 division trades. Levels two, three, and four provide progressively more detailed subgroupings. MasterFormat is used extensively throughout the industry as a format for project manuals, specifications, and project data. It is now the standard for various references accepted by sources such as R. S. Means Co., which uses it for unit cost publications, and Sweets, which uses it for product literature. Since the format resembles the basic form by which projects are procured (subtrades and contract packages), it is often used as a cost control, scheduling, and estimating framework, especially for detailed estimating.

MasterFormat provides an effective way to define building systems within single trades, but its use can be problematic for tracking the cost of building systems that span multiple trades. For example, an exterior wall system standard detail consisting of masonry block backup, insulation, and precast concrete panel would reference three sections from three separate divisions. This relates well to the means of specifying and constructing the wall, but the needs of the designer are somewhat different. The designer views the wall as a complete functional entity or system and can work more readily with a data format that uses a system or elemental approach to defining building components.

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An information format that relates better to the language of design is UniFormat II. It is particularly well suited to use during early design phases, when cost, budget, and performance aspects of building components are still conceptual. Using UniFormat allows estimates of building components to be gathered under one heading, regardless of the type of material being specified. Listing each element as a discrete functional building part facilitates cost and performance comparisons, regardless of the actual materials chosen. In addition, UniFormat II is hierarchical, which allows information (in particular, cost information) to be developed at different levels appropriate to the degree of information available. This flexibility is useful when specific material and system choices have not been made.

UniFormat is subdivided into 22 major building elements. The accompanying diagram shows a list of UniFormat II at levels one, two, and three. It demonstrates the hierarchical nature of the format and shows the relationship between UniFormat II and MasterFormat. Although UniFormat is commonly used, many owners require MasterFormat for detailed estimates. As a general rule, UniFormat can be used as a basic structure for preparing estimates during design development and construction documentation. Most of today’s computer systems and advanced spreadsheets allow for conversion from one format to the other.

uni-format-vs-masterformat-xlsx_001

Source: Detailed Cost Estimating, Michael D. Dell’Isola, PE, CVS; Excerpt from The Architect’s Handbook of Professional Practice, Update 2003 (AIA)
The Architect’s Handbook of Professional Practice: Update 2003

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