Choosing Insulation

There are more options for your addition than those rolls of pink fiberglass
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INTERIOR - Great Room - Rod Garcia installs insulation.

Photo by: Fred Hayes

Fred Hayes

By: Oliver Marks

Just a few years ago, insulating an addition (and any associated remodeling work) was a pretty simple proposition. Everyone used the same thing: Rolls of cotton-candy-like pink fiberglass. Well, those fiberglass "batts" remain the industry standard, but they're not the only game in town anymore. There are healthier and more effective choices that you can choose—for a price. Are they worth the increased cost? "The higher heating fuel costs go, the bigger the payback on the initial costs of your insulation," says New York City architect Dennis Wedlick. "And efficient insulation can have a better payback than efficient windows." Here's a rundown of four main options you can use to insulate your addition:

Fiberglass batts. Though they look cottony, these batts are made up of tiny strands of fiberglass. The batts are sized to fit perfectly between the standard spacing of the wood framing inside walls and ceilings and have a paper backing that helps block moisture from moving into the wall.

Pros: Fiberglass is inexpensive, effective and doesn't require a specially trained installer.

Cons: Fibers released into the air are unhealthy to breathe, though this generally affects only the installers because once the walls are closed up, the fibers don't get released anymore. Also, the material isn't very effective for odd spaces, such as behind outlets and wall switches.

Cotton batts. Unlike fiberglass, these batts really are as cottony as they look. They're made from recycled blue jeans, and therefore are a great choice for eco-conscious homeowners.

Pros: Cotton batting doesn't release unhealthy fibers into the air—and it's made from a waste product that would otherwise go into a landfill. It's also just as effective and easy to install as fiberglass and is actually a better soundproofing material.

Cons: It costs about 20 percent more than fiberglass.

Open cell foam. Rather than batts, this insulation is polyurethane foam that gets sprayed into the open framing of the walls and ceilings. It's known as open-cell foam because its air pockets aren't completely sealed, which creates a soft, lightweight insulation.

Pros: Provides higher insulation value and better draft protection than batts. Plus, because it's sprayed into place, it easily fills the small and awkward cavities that batt installers often miss.

Cons: "Foam isn't very economical yet," says Curt Schultz, a Realtor-architect-builder in Pasadena, Calif. It can cost more than two times the price of fiberglass.

Closed cell foam. This is a far denser foam, with sealed air pockets that contain an insulating gas instead of air, providing even higher insulation value than open cell foam.

Pros: Extremely high insulation value and draft-blocking capability, it's also moisture resistant and so dense that it literally strengthens the building.

Cons: It can cost more than three times the price of fiberglass—and if you ever need to snake in wires or plumbing in the future, you'll likely have to cut it out of the way first.

Next Up

Expanding Utilities Into Your Addition

Make sure your electrical and plumbing systems can handle the additional square footage

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