What two methods of installation affect the installed R-value for fill insulation?

The two methods of installation that significantly affect the installed R-value for fill insulation are pouring and blowing. Each method involves different processes that directly influence how effectively the insulation fills the spaces and the subsequent thermal performance.

When insulation is poured, such as with loose-fill material, it conforms to the shape of the cavity and settles into place, potentially creating gaps or voids if not done carefully. The effectiveness of this method depends largely on the installer’s ability to achieve an even distribution without leaving significant air pockets.

Blowing insulation, on the other hand, involves using a machine to pneumatically distribute insulation material into cavities or attics. This method allows for a more thorough filling of spaces, which can lead to a higher R-value as it minimizes gaps and ensures that the insulation is densely packed. Properly blown insulation tends to perform better in terms of thermal resistance compared to poorly installed poured insulation.

Other methods mentioned, such as stacking and layering, do not typically apply to fill insulation but rather to batt or roll insulation. Screwing and nailing are generally methods used to attach rigid insulation panels and are not relevant to fill insulation installation at all.