Q: The blown-in insulation in my attic is compressed and I’d like to add more. What is the easiest way to do this myself?
A: If you don’t need to add much insulation, you can purchase bags of loose-fill fiberglass or cellulose and install by hand. If you do have a big job ahead of you, then blowing machines can usually be found at the same place you purchase the insulation. You may have to rent them (or at least post a security deposit), but in some cases you may be able to use the blower at no additional charge to what you pay for the insulating material.
Another option is to switch from the blown-in type of insulation to rolls or batts. Unrolling fiberglass insulation can be an easy and inexpensive method to increase insulation levels. When the joist cavity is full, install the new layer of unfaced insulation perpendicular to the first, covering the ceiling joists to reduce heat loss through the wood.
If you install additional fiberglass insulation over existing insulation, be sure to use unfaced rolls or batts. The facing acts as a vapor retarder that helps reduce the amount of moisture entering a wall, ceiling or floor. In hot climates, the original layer of insulation should already have a vapor retarder facing the living area of your home. If you add a second vapor retarder with another layer of faced insulation, any moisture that does get through the first layer may condense on the second. This can cause water stains on the ceiling and could lead to mold and structural damage.