How to Insulate an Attic With Fiberglass and Foamboard
Though it's a home improvement that might not be obvious to outsiders, installing or adding to existing insulation in your attic is a way to save energy and reduce heating costs. Several types of insulation exist. Whether you're interested in installing foamboard or you'd like to layer existing insulation with polywrapped fiberglass batts, following a few basic steps can help ensure proper installation. Does this Spark an idea?
Things You'll Need
- Safety goggles
- Dust mask
- Protective clothing
- Foamboard insulation
- Caulk
- Plastic sheet or other coating
- Gypsum, if needed
- Polywrapped fiberglass batts
Instructions
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Installing Foamboard
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1
Wear goggles, a dust mask and protective clothing, such as gloves, long pants and a long-sleeved sweatshirt.
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2
Choose a thicker form of foamboard for your attic since you will be walking on it.
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3
Apply caulk on the attic supports and also along the walls.
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4
Lay the foam board, starting in one corner of the attic. If needed to get an accurate fit in angled areas, cut the foam board with a knife.
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5
Cover the boards with a dark plastic sheet or other dark material to protect them from sun damage.
Installing Fiberglass
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6
Choose polywrapped fiberglass batts to avoid inhalation of airborne glass fibers, which could be hazardous to the lungs. According to "Home Improvement for Dummies," this form of insulation is ideal for attics, as it can go easily over other types of existing insulation. In addition, because it's encapsulated in a perforated polyethylene covering, you will be exposed to fewer airborne fibers.
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7
Install polywrapped fiberglass batts at a right angle to existing insulation. Lay the batts perpendicular to floor joists. Polywrapped fiberglass batts resemble a sausage roll, so you'll easily be able to roll them out on your attic floor.
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8
Fit the batts to your attic's angles by cutting the insulation rolls with a knife or sharp scissors.
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1
Tips & Warnings
Search for insulation options with a high R-value per inch of thickness. R-value is simply the measurement of the resistance to heat flow. The higher your insulation's R-value, the more effective it will be in trapping heat.
You can also use polywrapped fiberglass batts to provide a vapor barrier. Purchase insulation with a perforated polywrap on one side and solid polyfilm on the other. To install this type of insulation, apply the vapor barrier side against the warm-in-winter side of the wall or ceiling.
The U.S. Department of Energy recommends using a certified insulation installer for installing foamboard. When obtaining quotes from contractors, ask what the R-value of the foam board is.
Though the U.S. Department of Energy says that foamboard is hard to ignite, it does burn easily and could emit toxic gases when it is ignited. Because of this, some areas require a 1/2-inch-thick layer of gypsum on the foamboard as a fire barrier.
