Attic Insulation Techniques
Loose-fill or batt insulation is typically installed in an attic. Although installation costs may vary, blowing loose-fill attic insulation—fiberglass, rock wool, or cellulose—is usually less expensive than installing batts and provides better coverage.
STEPS FOR INSTALLING LOOSE–FILL AND BATT INSULATION
- Seal all attic-to-home air leaks, especially chases, dropped ceilings, wiring and plumbing penetrations, light fixtures, and bathroom fans. Most insulation does not stop air flow.
- Install blocking (metal flashing) to maintain clearance requirements (usually 3 inches) for heat-producing equipment found in an attic, such as flues, chimneys, and exhaust fans.
- Use only IC-rated recessed lights because they are airtight and can be covered with insulation.
- Select insulation levels in accordance with the 1995 MEC or the DOE Insulation Fact Sheet. The Insulation Fact Sheet (DOE/CE-0180) can be ordered from the Energy Efficiency and Renewable Energy Clearinghouse or accessed from the Internet at www.ornl.gov… .
- Locate the attic access in an unconditioned part of the house if possible. Otherwise, weatherstrip the attic access and insulate it by attaching insulation to the cover or by installing an insulated cover box.
- If mechanical equipment or storage areas are located in the attic, elevate the attic decking to allow full-height insulation to be installed.
ADDITIONAL STEPS FOR INSTALLING LOOSE-FILL INSULATION
- Prior to hanging ceiling drywall, install rafter baffles to preserve ventilation from soffit vents and use insulation dams at the soffit, porch, garage, and attic access to prevent the insulation from spilling.
- Follow the manufacturer’s specifications (number of bags per square feet) to obtain complete coverage of the blown insulation at consistent depths and to avoid fluffing the insulation.
- As required by the 1995 MEC, make sure the installer:
- Provides attic rulers to show proper blown depth(facing the attic entrance, one ruler for every 300 sq.ft.)
- Provides an accurate attic “report card” showing that sufficient density was installed
ADDITIONAL STEPS FOR INSTALLING BATT INSULATION
- Cover the top of the ceiling joists or the bottom cord of the truss with insulation.
- Obtain complete coverage of full-thickness, non-compressed insulation. Make certain batts completely fill the joist cavities. Shake batts to ensure proper loft. If joist spacing is uneven, patch gaps in the insulation with scrap pieces. Do not compress the insulation with wiring, plumbing or ductwork (cut slits in the insulation if necessary).
When the attic access is located in the conditioned space of the house, build an insulated attic access cover to provide continuous ceiling insulation coverage and use blocking to prevent fullheight, loose-fill insulation from falling through the access