Estimating by square footage

Estimating construction cost by the square footage can be dangerous for several reasons. In this answer, I will explain some of the major pitfalls of this approach.
Firstly, construction cost per square feet varies significantly depending on the location. Also the complexity of the project, and the quality of materials used. Therefore, a one-size-fits-all approach may not be accurate. Relying on a single number can lead to a significant mistake or misestimate. For example, the construction cost per square feet in a high-end neighborhood may be much higher than that in a less affluent area. These can be due to higher labor and material costs.
Secondly, the scope of work can vary widely, even within the same square footage. For instance, one project may have a simple rectangular shape. Another may have complex architectural features such as curved walls or high ceilings. These variations can significantly affect the cost. Estimating based on square footage alone does not account for them.
Thirdly, the quality of materials and finishes can also affect the cost per square feet. For example, a project with high-end finishes, such as marble flooring and custom cabinetry, will cost significantly more than a project with standard finishes such as laminate flooring and basic cabinetry. If the estimated cost per square feet is not adjusted for these factors, it can result in a misleading estimate.
Fourthly, different building types have different requirements and costs associated with them. For example, a hospital or laboratory will have much higher construction costs per square feet than an office building due to the need for specialized infrastructure and equipment.
Finally, unforeseen circumstances such as weather events, supply chain disruptions, or changes in regulations can affect the cost of construction. If the estimate is based on a static cost per square feet, these external factors are not accounted for, resulting in an inaccurate estimate.
In conclusion, estimating construction cost per square feet can be dangerous because it oversimplifies the complex factors that go into the cost of construction. While it can be a useful starting point for estimating, it is important to adjust the estimate based on the specific project’s requirements, location, materials, and other factors. A more comprehensive and detailed approach is necessary for accurate cost estimation.