Add Attic Insulation Over Blown Insulation

Learn how one caller made an installation mistake and increased his chances of mold and condensation when he tried to add unfaced insulation over his blown in attic insulation.

Add attic insulation over blown insulation. How much does attic insulation cost. The vapor retarder on top of or between layers of insulation can trap moisture. When adding roll the insulation perpendicular to the joists not parallel. The pros charge 1 500 to 2 000 to do a 1 200 sq ft.

We offer our review of the three most popular types of attic insulation with a look at each one s pros and cons. The attic is the most important place to install insulation b ecause heat rises to make your home more energy efficient it is important to insulate the floor of the attic. When blown into attics and wall spaces loose fill fiberglass offers an average r 2 5 thermal value per inch the higher the number the greater the insulating effect. If you need to add insulation in your attic save big by blowing in cellulose insulation yourself.

Blown in insulation overview. Batt or rolled insulation or blown loose fill insulation fiberglass or cellulose can be installed on top of old insulation. You can do it yourself for about 500. If you use fiberglass over loose fill make sure the fiberglass batt has no paper or foil backing.

Find out how to install unfaced insulation correctly over blown in insulation. You can add loose fill on top of fiberglass batts or blankets and vice versa. It needs to be unfaced. When adding additional insulation you do not have to use the same type of insulation that currently exists in your attic.

Blowing attic insulation isn t hard but it s dusty sweaty work. Cellulose is recycled newsprint treated with a fire retardant. Fiberglass is just that thin fibers of glass that trap air. Blown in spray foam batts and blankets.

Do not tack down any rolled insulation. Attic insulation also prevents condensation bacteria and mold from forming on your framing members and plywood roof sheathing. Adding rolled batt or blown in insulation over existing insulation is not a problem. Don t add faced insulation on top of your existing insulation because the vapor retarder in between layers leads to trapped moisture.

Most attics are insulated with blown in loose cellulose r 3 5 per inch blown in loose fiberglass r 2 5 per inch or fiberglass batts r 3 2 per inch. Block all vents in the attic floor with baffles making sure to extend the baffles at least four inches above the planned thickness of your insulation. Insulation should be rolled out perpendicular to the joists and unfaced rolls should be used. 3 have a friend add material to the hopper.