What are the Different Types of Roof Insulation?

Margo Upson
Margo Upson

Installing efficient roof insulation is a great way to reduce heating and cooling costs. Roof insulation was not required in homes until the early 1970s. Because of this, there are a lot of older homes that do not have adequate insulation. When looking to update their homes, and install insulation, consumers have a lot of options.

Foam is a popular type of roof insulation.
Foam is a popular type of roof insulation.

One of the most popular types of roof insulation is fiberglass. Fiberglass comes either as sheets that can be applied to the roof from the inside, or as loose fibers, mixed with adhesive, that are blown into place. A new form of blown fiberglass mixes two types of glass that naturally curl. These fibers cling together, replacing the need for adhesive. This new product also is safer for the environment and causes less irritation when it comes in contact with skin.

The second most common type of roof insulation is cellulose fiber. Cellulose fiber insulates better that fiberglass, and offers customers a great quality for the cost. It is always treated with a fire-retardant chemical, making it a safer alternative than some other forms of insulation.

Foam can also be used as roof insulation. Polyurethane is one of the most common types of foam insulation. Some foam insulation is rigid -- cut to size and put into the correct place under the roof. This is easiest to do while building the house. Other foams are sprayed into place, and then expand to fill the space between the ceiling and roof. This is difficult to do as a do-it-yourself project, because it is hard to tell how much foam you have used until it expands. Use too much, and you may have to start over, wasting a lot of expensive material.

Recycled denim is an earth-friendly roof insulation alternative. Denim and cotton waste is treated with a fire-retardant chemical. It is sold in rolls, making it easy to install, and it won’t irritate the skin. Other earth-friendly roof insulation options include soy fibers and sheep’s wool. Sheep’s wool is often considered one of the best insulation types available, but it is also one of the most expensive.

Roof insulation is measured according to an R-value. The higher an insulation material’s R-value, the better it is at thermal resistance. This means that the house will stay cool in the summer, and warm in the winter. Sheep’s wool, and thick foam, has some of the highest R-values available. Even though these types of insulation cost more, homeowners will have much lower heating and cooling bills, and the insulation will more than pay for itself.

Margo Upson
Margo Upson

Margo has a varied academic background, which has involved everything from psychology and culinary arts to criminal justice and education. These wide-ranging interests make her an ideal wiseGEEK writer, as she always enjoys becoming an expert on new and unfamiliar topics.

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Discussion Comments


My hubby and I are do-it-your-self kind of people. The first house we ever bought was in really bad shape, but we got it at a good price.

Immediately, we set out to make our tiny cottage a miniature mansion.

One of the first things we realized we needed was good insulation in the walls and attic space. We chose to go with fiberglass. We installed it ourselves to cut back on the roof insulation costs.

It really wasn’t so bad once we figured it out. I’ll give you a hint, though. Wear long sleeves, because that stuff itches!


I’m telling you what; I grew up in a house that had no insulation at all. Add to that the fact that I had an upstairs bedroom and blazing 100 degree days in the summer, and you can imagine how miserable it could be.

However, I was determined to have a home when I grew up with not only decent insulation in the attic but – can you believe it – central heat and air!

Again, I’ll tell you what; those hundred degree days sure are a lot more pleasant now that I’ve got both!

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