This photo shows us what the air sealant looks like after being installed. The orange puffy stuff on the floor is ZypFoam, which is what seals all of the cracks in the floor which are potential points of air leakage from the conditioned part of the home to the attic. This step is crucial before adding the cellulose insulation. Adding that thick layer of insulation is almost pointless if you are not first air sealing the attic.