Attic Spray Foam Insulation: You Need To Know

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To reduce energy costs and consumption, consider adding attic spray foam insulation to your home. However, this process involves more than spraying foam into the attic.

Here, we explore installing spray foam insulation in the attic. We consider the costs, advantages, and disadvantages.

What Is Spray Foam Attic Insulation?

Spray foam insulation in the attic is an ideal way to keep homes adequately insulated. Its insulating process keeps external weather elements and moisture outside of the attic space. As a result, it prevents cold air infiltration or moisture penetration.

In effect, spray foam insulation in the attic forms an effective air barrier that seals cracks, crevices, and other holes. Furthermore, it offers the benefits of maintaining humidity levels while preventing the infiltration of pests, dirt, and dust.

Lastly, it provides thermal insulation. Specifically, it prevents heat transfer from one location to another within a property.

Primary Types of Spray Foam


High-density spray foam is the densest of all spray foams available. It uses a much higher volume of foam during the application, roughly 3 lbs. per cubic foot. The R-value of this spray foam is approximately 5.5 per inch.

Medium Density

Medium-density spray foam is a closed-cell foam insulation product that technicians apply at around 2.0 lbs. per cubic foot. It is ideal for insulation tanks or other structures resting on the roof. It also functions well as an envelope insulating building exteriors.

Low Density

Low-density or open-cell spray foam provides continuous insulation and an air-sealing barrier. The open-cell structure gives it the flexibility of hardened foam, weighing almost 0.5 lbs. per cubic foot. It is more cost-effective for sealing small cracks and gaps.

You can apply it in temperatures as low as 32°F, ideal for colder climates where high-density spray foam would freeze.

Spray Foam Attic Insulation Pros and Cons


  • Acts as an effective thermal insulator.
  • Blocks rodents and other pests from accessing the attic.
  • Prevents moisture retention. Too much moisture in the attic can lead to mildew or mold growth.
  • Rated as a class 1 fire retardant both for the attic and other open cavities. This rating means that spray foam can resist catching fire for about one hour.
  • Spray foam insulation is eco-friendly compared to other insulation types.


  • Spray foam can be costly compared to other forms of insulation.
  • Some open-cell spray foam brands have a strong, unpleasant odor.
  • The attic insulation installation process is too complex for DIY enthusiasts.

The 5 Benefits of Spray Foam Insulation

Prevents bugs, insects, and small rodents from getting into your home

Spray foam insulation fills tiny holes in your building structure. Therefore, it creates a strong barrier against intruders like ants, bugs, and rodents.

Increases the durability of walls

Spray foam insulation goes inside the cavities of your home’s exterior walls. As a result, the walls receive added strength, durability, and energy efficiency.


Spray foam is a 100% water-blown product that doesn’t emit HFCs or HCFCs, which can harm health and the environment.

Reduced dust and allergens

Spray foam insulation keeps out dust mites, mold spores, and other allergens.

Noise reduction

Low-density spray foam contains more air pockets, enabling it to absorb sound and reduce outside noise.

Spray Foam Attic Insulation Cost

The average spray foam attic insulation cost is between $1,284 and $3,741. Furthermore, the national average cost is $2,492. However, note that the cost of installing spray foam insulation varies widely according to your location, attic layout, property size, and amount of materials used.


 Attic spray foam insulation offers numerous advantages that other forms of insulation cannot match.

Contact Insulation Co, LLC today at (425) 903-6453. One of our representatives will be more than happy to answer any questions you may have. We can walk you through the insulation of attic with spray foam.

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