Florida Home Inspector Practice Test 2025 – Comprehensive Exam Prep

In an attic space, the vapor barrier's primary role is to impede the movement of moisture from the living space into the insulation. When installed correctly, it helps prevent condensation from forming within the insulation, which can lead to mold growth and deterioration of materials.

Placing the vapor barrier underneath the insulation ensures that it effectively blocks moisture that might migrate upward from the living area. This positioning also allows the insulation to function properly by trapping air, providing the necessary thermal resistance while keeping moisture from the interior environment out of the insulating material itself. The barrier must be located close to the warm side of the insulation, typically just beneath it, to maximize its effectiveness.

Considering other placements, such as above the insulation, would allow moisture to reach the insulation, which is counterproductive and can create a humidity problem. Positioning it beside or next to the insulation may not adequately prevent moisture from penetrating into the insulating material either, as there would be potential gaps or vulnerabilities. Thus, the correct location for the vapor barrier in relation to the insulation at a skylight well is indeed underneath the insulation.