How does the code dictate the installation of fiberglass batt insulation?

The code specifies that fiberglass batt insulation must fit snugly between framing members to ensure its effectiveness. This snug fit is crucial because it minimizes air gaps that can significantly reduce the insulation's thermal resistance, also known as R-value. When insulation is properly installed, it creates a continuous barrier that helps to maintain the desired indoor temperature by resisting heat flow.

Additionally, a snug fit prevents the insulation from sagging over time, which can happen if it is loosely placed. A sagging insulation batt can leave gaps that allow air to pass through, thereby diminishing its insulating properties. Proper installation also helps avoid moisture issues, as gaps can lead to condensation and potential mold growth. Therefore, adhering to the code's requirement for a tight fit is essential for both energy efficiency and building integrity.