Cost estimating can be time-consuming. It can also be dangerous in that wrong estimates may require time-consuming and expensive redesign. From the beginning of a project, responsibility for cost control (if any) should clearly be established.
If the architect is responsible for doing estimates, the architect should consider the following points:
Apples to Apples: In discussing costs and budgets with clients and builders, the parties must be sure they are comparing “apples to apples” (ie, what is included and excluded).
Examples of misunderstandings:
(1) Cost of land (is usually excluded).
(2) Financing costs (are usually excluded).
(3) Architectural / Engineering (A / E) fees (are usually excluded).
(4) City or government fees (are usually excluded).
(5) Is site work included or excluded in a value per square footage estimate?
(6) Are Furniture, Fixture, and Equipment (FF & E) costs included or excluded (usually excluded)?
Variables: The value per square footage figures for various building types are for average simple buildings. They may need to be modified by the following variables:
(1) Location. Modify costs for actual location.
(2) Historical Index. If cost data is old, modify to current or future time by often-published modifiers.
(3) Building Size. The value per square footage costs may need to be modified due to size of the project. Median sizes may be modified rough as follows:
As size goes down, cost goes up by ratio of 1 to 2.
As size goes up, cost goes down by ratio of 3 to 1.
(4) Shape and Perimeter. Increases in perimeter and more complicated shapes will cause costs to go up. Where single elements are articulated (eg, rounded corners or different types of coursing and materials in a masonry wall), add 30% to the costs involved.
(5) Height. As the number of stories goes up the cost goes up due to structure, fire protection, life safety issues, etc. For each additional story add 1% to 5%.
6 Quality of Materials, Construction, and Design.