Which of the following is NOT one of the four principles of effective insulation?

The principle relating to heavyweight materials is not considered one of the four principles of effective insulation. The primary objectives of insulation are to create a continuous thermal barrier, minimize air movement that can lead to heat loss, and manage moisture. The presence of gaps or voids can significantly reduce insulation effectiveness, making it crucial to achieve a complete coverage without interruptions. An air-sealed cavity or surface further helps in maintaining the desired thermal performance by preventing air leakage. Lastly, placing a vapor barrier toward the interior of living spaces addresses moisture control, which is critical for preserving indoor air quality and preventing potential damage to building materials.

In contrast, while heavyweight materials can have thermal mass properties, their use is not inherently linked to the fundamental principles of insulation effectiveness. The focus should remain on achieving proper sealing and coverage rather than the weight of the materials used.