Attics are generally treated with blown, loose fill cellulose, installed on the attic deck once it has been properly air sealed. Air sealing the attic deck is extremely important from a performance and durability standpoint. Conditioned air leaking into the insulation will compromise its’ effectiveness. It can also lead to problems such as mold growth, condensation, and ice formation on the interior of the roof sheathing. Even if an existing home has no history of these problems, adding insulation without air sealing can lead to them, as the resulting lower temperatures may not allow drying as before.

(Consistent depth of loose blown cellulose insulation maintained through use of “yardsticks” installed throughout the attic.)

Efficiency Maine prohibits its contractors from installing loose fill fiberglass due to its poor performance.