Detailed Quantity Estimating Design Stage 1 Preconstruction Stage 2: Procurement Conceptual Planning Stage3: Construction Stage 4: Project Close-out

Detailed Estimates A careful tabulation of quantity take-off multiplied by unit costs. Can only be prepared when the plans and specs are complete Must include indirect costs Must be accurate, some contracts will state a “ceiling amount”.

Should the Company Submit a Bid? Before a detailed estimate is prepared, some questions must be answered. Questions about: financial, legal, competition, and risk aspects. If the top management decides to bid, a detailed QTO is prepared, a site investigation is made, and the costs are computed.

Organization of the Detailed Estimate Estimating department is not the top management, and others besides the estimator will make reference to the estimate A standard method of estimating should be used. Estimates must be clear and neat, with complete descriptions. Every estimator’s approach within the same company must be the same.

In order to standardize the estimates within a company, different companies will develop different estimating manuals. Estimate forms are the basis for cost control, both better be organized in a similar way. Checklists may assure that some items are not missed

Site Investigation A visit to the site is part of the detailed estimate to avoid surprises and to look for favorable conditions After carefully studying the plans, the estimator will visit the site and gather information about: transportation availability, road conditions, public utilities availability, weather conditions, earthwork items, and other various possible problems such as: noise, dust, traffic, and access to the site. See Figure 7.1. The estimator will take pictures and may recommend to dig test pits. In case of a remote site, the estimator will need information about the local labor conditions, housing, and local suppliers and subcontractors.

The Quantity Take-Off (QTO) An estimate consists essentially of the quantity of each item and the price per unit. QTO includes the in-place quantities as well other material such as shoring, forms, etc. Quantities must –be taken for each item in the same units as the unit of pricing. –be taken in whole multipliers of the modular dimensions of materials and allow for cutting and trimming. The number of 9”X 9” tiles needed for a floor 10 X 20 ft is not simply 10 X 20 X 144 /(9X9) = 356 tiles. It should be 14 X 27 tiles = 378 tiles.

–allow for overlapping of material (reinforcing bars, roofing material, welded wire fabrics, etc.) –include sub-activities. –include additional allowances (5 to 25%) for some items for reasons such as breakage, waste, or theft. Do not include an allowance twice: overlap of rebar is included once.