Cellulose insulation is just a loose-fill product made up of pulverized recycled paper treated with fire retardant. Unlike conventional fiberglass installed blankets called “batts,” cellulose is blown into attics and walls beneath air pressure through a hose. Cellulose offers a higher R-value — the measure of their capability to retard heat transfer — compared to fiberglass. Therefore, less thickness must produce the specified insulating value. Because cellulose is just a loose-fill material, it can easily be blown into odd-shaped spaces in a attic or wall, typically providing more complete coverage than fiberglass batts that require labor-intensive cutting and fitting to cover all of spaces. A typical installation is a two-person task demanding a blowing machine with a hopper to feed the cellulose, plus a 3-inch hose up to 200 feet in length to spread the insulation.
Are Air Leaks Sealed?
Proper installation starts before cellulose is added. While cellulose insulation retards heat transfer by conduction, it’s far less effect on heat transfer from direct air leaks. Sealing air leaks should be the first step of any professional cellulose installation. After cellulose is installed in an attic, air escapes covered by the insulating material may be difficult to detect. These unseen leaks will continue to allow air to flow into or from living spaces below, wasting energy.
Is It The Correct Depth After Settling?
Cellulose insulation installs as fluffy, aerated material that settles over the following weeks and months. The thickness required to accomplish the proper R-value is based on the settled thickness in inches. A professional installer will compute proper depth of cellulose insulation with the addition of no less than a 13 percent tolerance for settling. An installation that needs 12 inches of cellulose to achieve the desired R-value should have an initial installed thickness of approximately 14 inches to compensate for eventual settling.
Does this Cover Lights?
Cellulose insulation installed in the loft should not contact recessed ceiling lights unless the lights have the Underwriter’s Laboratory IC (insulation contact) rating. Depending on local building codes, before the cellulose is blown in an enclosure may be necessary above non-IC recessed lights to maintain insulation a minimum of three inches apart from the fixture. In certain places, cellulose cannot be added to an attic with non-IC lights under any condition, demanding replacement of light fixtures.
Is The Chimney Insulated?
No installed cellulose should get in touch with an uninsulated chimney that passes through the loft. Installers should maintain at least 2 inches of clearance between the insulation and the masonry of this chimney. Cellulose may be installed in direct contact with the chimney only if the chimney is wrapped with a mineral wool batt to insulate chimney heat.
Are The Wall Cavities Full?
Cellulose is blown into existing walls via holes bored into the wall cavity between studs, usually from the exterior of the home. Following the cellulose was installed, the holes are closed. Insulation sealed inside wall cavities could be evaluated by means of an HVAC technician using a thermographic camera that images heat transfer through the wall. Areas where the level of insulating material is missing or substandard appear to be red heat plumes on the imaging screen.
