Attic Insulation Batts Over Blown

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.

Attic insulation batts over blown. Pull back the existing insulation and use expanding spray foam the fire blocking type to seal any. This will lead to non uniform r values. You d need a thickness of. Install or repair vent chutes.

Batt or rolled insulation or blown loose fill insulation fiberglass or cellulose can be installed on top of old insulation. It is sold in bags and made of materials that are of varying degrees of recycled. 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. Position the new vent chute so the.

That s because blown insulation is great at filling the gaps and giving you a good complete layer of insulation. Batt insulation is that it is a form of loose fill insulation as opposed to a flexible blanket. Since the attic usually does not have any wall on the other side this insulation makes some sense in that regard. Notice how you don t see any of the ceiling framing down at the ceiling level.

The r factor of blown in fiberglass is usually 2 3 to 2 8 per inch of material. Blown in insulation in the attic seal attic bypasses. Pull the existing insulation away from the roof. Blown in insulation thickness can vary in an attic space.

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. 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. That is about the only location that this insulation is used anymore as it is distributed uniquely.

Any existing batt or roll insulation in the attic should have the facing against the attic drywall floor or no facing at all. 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. Cellulose is recycled newsprint treated with a fire retardant. In short there is less chance of error with blown insulation as compared to batts.

Fiberglass is just that thin fibers of glass that trap air. Insulation should be rolled out perpendicular to the joists and unfaced rolls should be used. Once installed and expanded to the uniform manufactured thickness batts offer a known r factor.