Lifespan of Attic Insulation
As per International Association of Certified Home Inspectors, any type of insulation can last from 80 years up to 100 years or more.
What is the Best Type of Insulation?
Blown in fiberglass or cellulose insulation is considered to be much better than the spray foam due to the significant difference in cost.
Advantage of Blown-in Fiberglass Over Cellulose Insulation
Loose filled insulation is considered to be the best among all types of insulations, and fibreglass is considered better. It is moisture resistant – the insulation protects against mold and wood rot as compared to cellulose because it is made up of glass and sand, unlike paper as in cellulose insulation. The thickness of fibreglass insulation required is much less compared to cellulose insulation.
Recommended Insulation for Retrofitted Existing Wood-Frame Buildings
Uninsulated Attic – R49 to R60
Existing 3-4 inches of insulation – R38 to R49