What are three requirements for a substrate before installation?

The correct answer is based on the foundational principles necessary for ensuring proper adhesion and performance of air barrier materials. For the installation of an air barrier system, the substrate needs to be clean to remove any contaminants such as dust, dirt, oil, or residue that could hinder the bonding process. A sound substrate means it must be structurally stable and capable of supporting the air barrier system without any defects that could compromise its integrity. Being dry is crucial because moisture present on the substrate can interfere with adhesion, leading to potential failures in the air barrier performance over time.

While other options present certain important aspects, they do not fully encompass the critical criteria needed for a successful installation of an air barrier. For example, while the idea of rough surfaces may be beneficial in some contexts for mechanical bonding, it does not capture the structural integrity required. Similarly, durability is important but does not directly address the immediate prerequisites for application. Flat and smooth conditions might enhance aesthetic aspects or certain bonding types, but again, they do not replace the need for a clean, sound, and dry surface which is fundamental to the success of air barrier installations.