Which type of requirement specifies exact construction methods?

• A. Prescriptive
• B. Functional
• C. External
• D. Performance

Answer: (A)

Understanding how requirements are written in construction documents helps you see how a project can be built. Prescriptive requirements specify exact construction methods, including which materials, products, installation procedures, and sequencing must be used. When the owner needs tight control over how something is built and wants to minimize deviations, this precise direction is used. For example, a prescriptive spec might mandate a specific concrete mix, curing method, and formwork details to ensure the exact outcome is achieved.

In contrast, performance requirements describe the desired result or outcome (such as strength, durability, or energy performance) and allow the contractor to choose the methods to meet those goals. Functional requirements focus on what the system must do from the user’s perspective, not how to construct it, and external requirements refer to constraints or interfaces outside the built element. These do not mandate exact construction methods, which is why they aren’t the correct choice here.

So, the type of requirement that specifies exact construction methods is the prescriptive approach.