Prescriptive specifications describe required materials (including product options) for installation methods and activities to complete different aspects of a construction project. The idea here is that all products specified within this type of specification must be used for the project to meet its performance requirements.

The main advantage of a prescriptive specification over a performance specification is that it allows contractors, material manufacturers, and product consultants to use their own products to comply with all design objectives for the project without having to contact the building owner or contractor for approval each time something needs changing.

Prescriptive construction specifications can be divided into three categories: general provisions, required products and execution procedures. General provisions are building codes and standards for the state, but also nationally, and must be compiled by contractors.

Most building code provisions are “prescriptive,” meaning that they lay out a recipe for the work, with specifications for both the material and installation.