How Attic and Roof Insulation Help Your Roof Do Its Job

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Do you ever run your furnace in the winter but the house just never actually warms up properly? If this sounds like your house, then it’s time to take a look at what might be causing this heat loss. You might not think of it right away, but one of the first places you should check is at the top of your house. Since heat rises, you’ll want to see if there’s a leak in the roof or potentially insufficient attic or roof insulation. The status of your roof and insulation are essential to retaining the heat your HVAC system is circulating.

To preserve the heat your furnace is creating (and you’re paying for), it makes sense to call a professional, such as Interstate Roofing, to see if there are any leaks or if it’s time to repair your roof or add more attic or roof insulation. To find out more about how attic and roof insulation help your roof do its job, continue reading below.

What Are Attic and Roof Insulation?

According to, the roof and attic are primary sources of heat loss from a house. Insulation is a layer of material with low thermal conductivity—meaning heat doesn’t flow through it very well. Good insulation installed beneath the structure of your roof and around your attic space will help your home retain heat that would otherwise be lost through the top of your house.

How and with what material you insulate will depend on the sort of roof you’re insulating, such as a pitched vs. a flat roof. It also matters whether you’re installing warm or cold insulation. With a cold roof, the insulation must go to the joist level to prevent heat from escaping outwards. A warm roof means that there will be insulation under the rafters of the roof to prevent heat from escaping, assuming you’re using the attic space and want to keep it warm all the way to the top.

Having attic and roof insulation in the building design assures that you can keep a comfortable environment for the occupants of the home. Having quality insulation in your roof and your walls prevents heat loss, keeping the heat you do have inside, but it also works to prevent excessive heat from entering your roof and home and helps keep things cool during hotter months.

It’s important to note that there is no way to completely prevent heat loss, but there are materials that significantly decrease the loss.

A Quick Intro to the R-Value Number

The R-Value of insulation measures its ability to resist heat transfer. A higher R-Value means that the insulation is more effective and efficient than insulation with a lower R-Value.

You can learn more about the building code in your state, and that will help give you more insight to determine theR-Value climate zone to which you belong. This information is relevant to your insulation needs.

What Are My Top Insulation Options at Home?

Spray foam insulation: open- and closed-cell SPF

One option is spray foam. It starts off as a liquid and then hardens. It’s made of polyurethane and isocyanate and provides a durable layer to fill gaps, cavities, cracks, and corners where there might be air leaks. This sort of insulation may also contribute to mold and mildew prevention. The two types are called closed-cell and open-cell. The closed-cell is more expensive but provides better coverage and has an R-Value of 4.9 to 7.1 per inch. Open-cell, while still pricey, only has an R-Value of 3.5 to 3.6.

Loose-fill or blow-in insulation

This type of insulation is nearly as common as spray foam, but it’s made from loose fibers of recycled waste and filled into bags or flexible tubes. The material inside could be fiberglass fibers or cellulose. If there is unfinished wall space that still needs insulation, this could be a good choice. The R-Values vary. They’re between 2.2 to 2.7 per inch for fiberglass blow-in, and cellulose blow-in is higher, at 3.2 to 3.8 per inch.

Insulation blankets: batt and roll insulation

Insulation blankets are commonly used to insulate attics and roofs. They are pre-cut and therefore easy to install. They work well in framed spaces. There are two thicknesses for the material: 16 and 24 inches. There is also the possibility of layering them, and they are perfect for the longer stretches of housing. They come in fiberglass or mineral wool materials. Their R-Value is between 3.0 and 3.3 for the mineral wood.

Rigid foam board

Unlike the spray foam, this rigid board has already hardened. It’s a less expensive material to use for roof insulation, and it also has sound-proofing traits. Although this might start to sound like a good option for your home, it’s important to note that it’s only approved for use on the outside of the house as exterior insulation.

Whichever insulation type is the right fit for you, it’s imperative to have a professional visit the attic and roof space to identify any leaks. There are many do-it-yourself channels that provide instruction on the installation of insulation, but only a professional company can guarantee that the insulation is installed correctly and provide a warranty on the work done. They will be able to use their training to make sure that the insulation is installed both properly and effectively.

If you suspect your house is losing heat due to issues with your attic and roof insulation, it’s time to call a reputable and professional roofing team to complete an inspection of your roof and take a look at the insulation situation. If you live in the Portland area, look no further than Interstate Roofing. Schedule an appointment today.


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