Attic Insulation Batts Over Blown

The first difference in blown in vs.

Attic insulation batts over blown.

Batt or rolled insulation or blown loose fill insulation fiberglass or cellulose can be installed on top of old insulation. 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. It is sold in bags and made of materials that are of varying degrees of recycled. The photo above shows an attic insulated with blown cellulose.

You also don t see any gaps that allow you to see all the way down to the ceiling drywall. Blown in insulation thickness can vary in an attic space. That is about the only location that this insulation is used anymore as it is distributed uniquely. The material which is a combination of fiberglass and cellulose is blown in chunks to fill up space.

I don t know about that but it s a common insulation material that works much better in the blown form than in batts. Pull the existing insulation away from the roof. Once installed and expanded to the uniform manufactured thickness batts offer a known r factor. In short there is less chance of error with blown insulation as compared to batts.

You d need a thickness of. Batt insulation is that it is a form of loose fill insulation as opposed to a flexible blanket. Insulation should be rolled out perpendicular to the joists and unfaced rolls should be used. Blown in insulation in the attic seal attic bypasses.

You need about 22 inches of blown in or about 19 inches of unfaced insulation in that attic space to give you the maximum amount of warmth. 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. The r factor of blown in fiberglass is usually 2 3 to 2 8 per inch of material. Install or repair vent chutes.

Any existing batt or roll insulation in the attic should have the facing against the attic drywall floor or no facing at all. With this method the insulation is simply blown onto the attic floor and no matter what type of joists studs or wiring that may be in play the blown insulation will naturally form itself tight around any of these creating a layer of strong insulation. Since the attic usually does not have any wall on the other side this insulation makes some sense in that regard. Pull back the existing insulation and use expanding spray foam the fire blocking type to seal any.

Position the new vent chute so the. Cellulose is recycled newsprint treated with a fire retardant. Fiberglass is just that thin fibers of glass that trap air.