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Best Residential Applications For Closed Cell Spray Foam Insulation

November 1st, 2023 | 3 min read

By Kilian Agha

You're considering closed cell spray foam for your home project and want to make sure it's the right choice. Since every insulation product has its strengths and weaknesses, weighing the pros and cons is an essential step in the process. Before committing to closed cell spray foam, you must ensure it will work well for your project.

South Central Services has insulated hundreds of homes near Greencastle, PA with spray foam. One of our responsibilities is to provide product information clearly so our customers can make informed decisions. This article will explain what closed cell spray foam is best used for in residential applications, so you can feel confident in your decision or be directed to another option.

By the end of this article, you will know:

  • Which home improvement project types are best suited for closed cell spray foam
  • Which substrates closed cell spray foam adheres best to
  • Whether closed cell spray foam is the best choice for your project

Ideal Project Types For Closed Cell Spray Foam

Project type is one easy way to determine if closed cell spray foam is the product for you. If you know where your home needs insulation, you can evaluate potential insulation products more quickly.

Closed cell spray foam is an excellent option—or the only option—for four key project types. Here's a preview.

  1. Attic insulation
  2. Exterior walls
  3. Basements
  4. Crawl spaces

Let's examine each of these in more detail.

1. Attics

There are many options for attic insulation. Closed cell spray foam is one of the best options. Whether insulating the roofline to create a livable attic space or insulating the floor to protect the atmosphere of the primary levels, closed cell spray foam is a great product to use.

A roof insulated with closed cell spray foam insulation.

Why is closed cell spray foam so effective in attic applications? Closed cell spray foam has both an air barrier and a vapor barrier. The air barrier creates an airtight seal, preventing unwanted air leakage in your home. Air leakage can bring unconditioned air inside, allowing expensive conditioned air to escape outside. Closed cell spray foam eliminates this problem.

If your attic would require or benefit from a vapor barrier, closed cell spray foam has one built-in. Other insulation products require separate purchases and installations to get all the features that closed cell spray foam offers on its own.

2. Exterior Walls

Closed cell spray foam is not the only option for exterior walls. However, we often recommend closed cell foam because of its air and vapor barrier capabilities. In our climate zone, Climate Zone 5, exterior walls require vapor barriers. For homes in our service area of southern Pennsylvania, using closed cell spray foam eliminates the need to find and install a separate vapor barrier product.

Exterior walls insulated with closed cell spray foam insulation.

Exterior walls are a critical insulating area in homes. They form the literal barrier between your home and the outside world. The insulation in exterior walls should be high-performing to make as effective of a barrier as possible. With closed cell's air barrier, exterior walls avoid contributing to air leakage problems.

3. Basements

Closed cell spray foam is the only insulation that should be installed in basement applications. Basements are below-grade applications, meaning they're below the ground. Below-grade applications have higher moisture content and can't successfully use insulation products like fiberglass or cellulose.

A basement wall insulated with closed cell spray foam insulation.

Closed cell spray foam is not waterproof, but it is the only insulation considered flood-resistant. If your basement faces liquid water leakage, you could dry out your closed cell spray foam instead of replacing it. While closed cell foam is not a waterproofing product, it gives peace of mind to know that an unforeseen leak may not ruin your insulation. If you do have a leaky basement facing water seepage, you'll need to address that issue before insulating.

4. Crawl Spaces

Crawl spaces are often encapsulated, which involves an insulation product and a vapor barrier membrane. Since crawl spaces are below-grade, they need insulations approved for below-grade use.

An encapsulated crawl space in Pennsylvania with wrapped pillars, a vapor barrier floor, and closed cell spray foam on the walls.

Closed cell spray foam is one of the only insulations that can be used in below-grade applications.

Ideal Substrates For Closed Cell Spray Foam

Closed cell spray foam can be installed against many substrates in Climate Zone 5. If you live in southern Pennsylvania or nearby in Maryland, Virginia, or West Virginia, closed cell spray foam will adhere to almost any residential building material.

The three types of substrates that closed cell foam adheres well to include wood, metal, and masonry. Let's examine each of these in more detail.

1. Wood

Wood is one of the most common building materials. Closed cell spray foam forms a strong adhesion to wood. Whether you're creating a brand-new home or upgrading your current home, chances are that there is wood involved.

A spray foam insulation contractor installing closed cell in an attic. This overhead spraying will create an encapsulated attic.

2. Metal

Closed cell spray foam can be installed on metal roofing, siding, or garage doors. Metal is a good heat conductor, which means heat can easily transfer through it. By adding a layer of closed cell spray foam to the metal, you can preserve the expensive conditioned air you pay for.

A metal pole building, its walls and ceiling insulated with closed cell spray foam.

3. Masonry, Concrete, And Brick

Masonry, concrete, and brick are all unique in their ability to sweat. These substrates transfer water vapor. Because closed cell spray foam creates a vapor barrier, it is one of the best insulating materials for these substrates.

The Bottom Line About Where To Spray Closed Cell Spray Foam

Closed cell spray foam can be installed almost anywhere in residential applications. For homeowners considering retrofit upgrades like attics, crawl spaces, or basement insulation, closed cell spray foam is a great option. In new construction homes, closed cell spray foam can also be used for exterior walls.

If you have a residential project, you can't go wrong with closed cell spray foam. However, to save some money, you may want to consider using open cell spray foam when the application fits.

Now that you know where closed cell spray foam can be installed, your next step is to:

Kilian Agha

Kilian has co-owned and operated South Central Services for 8 years. He is passionate about community involvement. In his spare time, he enjoys being with his family, playing ice hockey, and going fishing with friends.