It typically costs about $2,450 to install spray foam insulation, and most projects range in price from about $1,700 to $3,200. The overall cost of your project will depend on the size of the area you’re insulating, the thickness of the foam and whether you use open- or closed-cell spray foam.

• How much does spray foam insulation cost?
• Where should you use spray foam insulation?
• What are the types of spray foam insulation?
• What is the R-value and thermal resistance of spray foam?
• Is spray foam insulation worth it?
• What is the installation process?

Spray foam has become a popular insulation material for both new construction and existing homes because of its energy efficiency, ease of installation and long-term value. Hiring an experienced insulation contractor will help ensure the most successful outcome.

You’ll see spray foam often measured and priced in board feet, which is a measurement of volume. One board foot equals 12 inches by 12 inches by 1 inch. To calculate the amount of spray foam insulation you’ll need, multiply the square footage of the area you’re working on by the depth of the wall cavity in inches.

It’s important to distinguish between board feet and square feet, as the depth of the wall cavity you need to insulate can greatly impact the cost of your insulation project. For example, a wall that is 10 feet wide by 10 feet tall with a three inch deep wall cavity is 300 board feet, while the same wall with a one inch deep wall cavity is only 100 board feet. The wall with the greater thickness will cost more than the thinner one to insulate.

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Spray foam insulation can be used in new or remodeled homes. Because it can expand to fill small and hard-to-reach spaces, spray foam insulation is especially useful for filling irregularly shaped spots and small gaps between materials. Some effective uses include:

• Attics
• Basements and crawl spaces
• Wall cavities
• Around HVAC systems
• Around windows, doors and other irregularly shaped spaces
• In roofs and under floors

There are two main types of spray foam, which a professional can help you select from based on how much foam you need, where you plan to use it and how much money you’d like to spend. Both types of spray foam insulation are typically made with polyurethane.

Open-cell foam, also called half-pound foam, is lighter and less dense, with more of a spongy texture. It is less expensive, but has a lower R-value, roughly 3.5 per inch, and provides less insulation. While it does provide an air seal, it won’t protect against water, so it shouldn’t be used below ground level.

Closed-cell foam, also called two-pound foam, is denser, more rigid and more expensive to install. It has a higher R-value than open-cell spray foam insulation, roughly 6.5 per inch, and therefore provides more protection against heat loss. Because it is less permeable, it can act as an air and vapor barrier.

Insulation is a way to keep heat from entering or escaping a building, keeping it warm in the winter and cool in the summer. Insulation materials are measured by their R-value, which indicates their thermal resistance or ability to prevent heat from escaping. The higher the number, the better a material’s thermal resistance.

The R-value of open-cell spray foam is roughly 3.5 per inch, and closed-cell foam is roughly 6.5 per inch. The additional benefit of spray foam is that it is also an air barrier, not only insulating walls but also plugging any air holes or leaks. If you use closed-cell foam, you can also prevent water and moisture from penetrating.

Learn more about heat loss and the building envelope

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Spray foam insulation has become a popular counterpart to fiberglass batting insulation. While its upfront cost will be more than batt insulation, spray foam should be considered for your new or existing home for the following reasons.

• Tight seal: Spray foam fits into small and irregularly shaped areas in a way that other insulation materials cannot. It is considered very effective at protecting against heat loss and air leaks, and can even help as a sound barrier.
• Long-term value: While spray foam may cost more upfront than fiberglass insulation, it can help lower energy bills and save money over the years.
• Health protection: Spray foam can also act as a water barrier, preventing moisture from entering the home and causing mold or mildew.

The main issues that can come with spray foam insulation often are a result of poor preparation or installation, such as the foam’s starting to pull away from the neighboring material, holes left in the foam layers or uneven application. These issues reinforce the value of hiring an experienced professional to install your insulation.

Spray foam is sprayed into place. Two liquid ingredients are mixed together beforehand and sprayed onto the surface that they will be insulating through a heated hose. A chemical reaction occurs between the two ingredients, causing the materials to foam and heat up inside the hose. The material expands and eventually hardens in place.

While it’s possible to install spray foam on your own using a DIY spray foam kit, it’s highly recommended that you rely on the expertise of a professional insulation installer. Experienced professionals have the knowledge, tools and expertise that will help give you the best result and can help avoid incorrect insulation selection, improper installation and possible safety hazards that may come from lower-quality materials.

Want more information? Read more on the basics of spray foam

Note: Costs are estimated at the U.S. national level. Variations depend on factors such as the quality of materials, type of products installed and labor costs. The typical range is assumed to be between the 20th and 80th percentiles. The high-end and low-end costs are the maximum and minimum, respectively. Costs assume that the homeowner manages the project and hires subcontractors as needed. They include a subcontractor markup of 10% for materials and labor. Costs can be higher if a general contractor is managing the project. All numbers are rounded.

Source: 2019 Houzz Remodel Costs Database