Architects know that the “bricks-n-sticks” building cost is only one component, albeit a significant one, of the total project cost. While this point is second nature to architects it is often lost on clients during early project planning. In their seminal work on architectural programming, Problem Seeking, William M. Peña and Steven A Parshall wrote
It is imperative to establish a realistic budget from the very beginning. Realistic budgets are predictive and comprehensive. They prevent major surprise. They tend to include all the anticipated expenditures as line items in a cost estimate analysis. The architect must look to past experience and published material to derive predictive parameters.
The budget depends upon three realistic predictions: (1) a resonable effficiency ratio of net to gross area, (2) cost per square foot escalated to mid-consruction, and (3) other expenditures as percentages of building cost. These predictions have become so common a practice that they are not considered predictions but as planning factors.
The method outlined in Problem Seeking was the inspiration for the Cost Estimate Analysis feature in Architactile Inception Jr. By starting with the building costs (determined from summing all defined Use Groups) and then applying percentages for each subsequent line item, a complete project budget can quickly be created.
For multiphase project in Inceptoin Jr. separate analyses are performed for each phase.
