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Have you been feeling a little cold in your house lately? Noticing your energy bills creeping upward? Seeing areas of your roof where snow melts more slowly than others? Perhaps you’ve detected moldy odors in your attic or seen mold growing on the framing.
All these signs indicate you need more attic insulation.
Attics need to be thermally separated from the rest of the house to keep warm air out. Warm air raises humidity levels, which promotes mold growth. It also heats up the roof and creates ice dams that break down the roof covering and cause leaks. And, of course, losing heat through a poorly insulated ceiling will drive up your heating costs
There are many types of attic insulation. One factor to consider when choosing between them is how much thermal protection your attic needs.
R-value, a measure of thermal resistance, varies by location. R-30 is the minimum requirement in Southern states and R-49 for Northern states. Ease of installation is another thing to think about, especially if you plan to do the work yourself.
There are also environmental considerations, although most insulation materials are made from abundant or recycled materials.
Here’s a rundown of the four types of attic insulation materials and installation methods at your disposal.
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Fiberglass Insulation
Air is one of the best thermal insulators, and fiberglass insulation makes use of it. Manufactured from glass fibers, fiberglass is woven into loose cotton candy-like bundles that can be installed multiple ways:
- Batts are bundles of a pre-determined thickness sized to fit snugly between the attic joists. You can buy batts with Kraft paper facing for walls, but in the attic they should be unfaced to allow the fiberglass to breathe. They’re installed by laying them in place and stuffing extra insulation in gaps around pipes, electrical boxes and other obstructions.
- Rolls are the same width as batts and about 40 feet long. They’re easier to install in long attic bays.
- Loose-fill fiberglass is typically installed with a blower. This method is easier and less time-consuming than laying batts, and allows you to adjust the thickness to achieve the optimum R-value. Blowing in loose fill supplements an attic with some insulation, but not enough. Just buy the insulation, rent a blower and have at it. Be sure to wear protective clothing, a respirator and goggles to protect yourself from the glass fibers. They aren’t carcinogenic like asbestos, but are still irritating and can cause respiratory distress.
