Blown In Insulation Over Batts

Rolled insulation should not be tacked down.

Blown in insulation over batts.

Once installed and expanded to the uniform manufactured thickness batts offer a known r factor. Blown in insulation thickness can vary in an attic space. The r factor of blown in fiberglass is usually 2 3 to 2 8 per inch of material. Blown in varieties however typically reach a peak of around a 2 8 r factor.

This light as air insulation is manufactured from glass that is heated to a liquid and then spun. Loosely blown fiberglass alone carries an r value of about 22 to 27 per square foot. This will lead to non uniform r values. The depth and thickness of the blown insulation affect the r value.

There are three types of blown in insulation. Insulation should be rolled out perpendicular to the joists and unfaced rolls should be used. For eco minded homeowners cellulose is often the insulation of choice because it s made from finely. Find out how to install unfaced insulation correctly over blown in 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. Compared to blown in insulation batts can reach a resistance rating r factor of over 3 1. The insulation usually is blended and provides an r value ranging from around 32 to 38 per square foot. Disadvantages of batt insulation.

Batt or rolled insulation or blown loose fill insulation fiberglass or cellulose can be installed on top of old insulation.