Considerations When Installing Spray Foam Attic Insulation

Spraying foam insulation in a the walls of a house under construction.

What are the advantages and things to consider when sealing the attic of a house with spray foam insulation? -Mike

The biggest advantage to applying spray foam insulation to the rafters in your attic is that you’ll be creating a more energy efficient envelope around your home, which means you’ll be spending a lot less energy and dollars on heating and cooling.

However, you’ll need to take into consideration:

  • Cost: Spray foam insulation isn’t a DIY project and it’s a very expensive upgrade. Unless you plan on being in your home for many years, adding more fiberglass or cellulose insulation may be more cost effective.
  • Existing Insulation: Any insulation between the ceiling and the attic will need to be removed when installing spray foam insulation on the rafters.
  • Attic Ventilation: Any gable, soffit, louver, or power vents in the attic will need to be removed or sealed shut, since the entire attic area will be turned into conditioned space.
  • Windows: A well-insulated and sealed attic will have only minimal effect if you still have leaky, single-pane windows.

Good luck with your project,


Further Information


  1. I live in Jackson, MS and I want to know where can I purchase the spray foam insulation and how cost effective is it for an older home.

  2. When installing closed cell spray foam insulation in the attic rafters does the roof deck need to be vented some how so the deck can breath and shingles last longer?

  3. I had a Home Energy audit done in January of this year and I was informed that the insulation I had done in November 2014 is not enough. We have ice dames and both sides of the house along with huge ice sickles. It is still cold upstairs and is usually very hot in summer. Area insulated is in the dormers. Fiberglass and some foam in floor was used. Basically a waste of money since it will have to be removed and redone with spray foam.

  4. Hi Danny,
    I have just purchased a new central heating and air conditioning unit. I really need insulation from a reputable contractor. My house is an old one and basically has no insulation. Who do you recommend?

  5. Hello Danny, I live in New Boston Michigan. Can you recommend a highly reputable insulation company to insulate my attic with cellulose. I have around 2600 sq ft to insulate.

  6. Even though spray insulation is expensive, it definitely seems like a worthwhile upgrade! If not only for just the resale value. For me, I would prefer buying a home, and would pay more, if it had spray on insulation.


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