What percentage of sagging is acceptable for cellulose?

Dépending on the amount sprayed, on a horizontal surface, compaction can vary from 7% to 10%.

In the case of an attic where cellulose is sprayed to obtain a R50 rating, the thickness applied, which would be 15.5 inches, could settle from 11% to a maximum of 15%, depending on conditions of the installation.

For the walls, where the minimum density of 3 pounds per cubic foot (3.0 lb / ft3) has been met, and where the installation was performed by a qualified applicator, there is no sagging.