Open Cell vs. Closed Cell Spray Foam Insulation For Your Attic
While spray foam insulation may appear to look the same, it’s offered in both open cell and closed cell. Which material your insulation contractor opts for can have a significant impact on your attic’s R-value and the overall energy efficiency of your home. Here’s what you need to know.
Consider Density When Selecting A Type Of Spray Foam Insulation
One of the biggest differences between open cell foam insulation and closed cell foam insulation is their densities. Closed cell insulation is heavy and inflexible, where open cell spray foam insulation is more flexible and forgiving. The type of application should be taken into consideration when deciding which type of spray foam insulation to use. For example, in a home with new electrical, open cell tends to work better because it is easier to manipulate. However, in a shed, the closed cell’s rigorous properties work well because it can better withstand impact.
Expansion Rate of Open Cell & Closed Cell Foam Insulation
Another way in which the two materials vary is how much they expand when they are applied. Open cell insulation has a much greater expansion rate, also known as high expansion foam, which is helpful when trying to fill all surface crevices in attics, rim joists, and crawl spaces. Closed cell or low expansion foam has a much lower rate which works well in other scenarios.
High Expansion Foam Helps With Sound Reduction
If one of the major goals of the spray foam insulation project is to reduce noise, open cell spray foam insulation will do a better job. This is because it expands at a higher rate and can fill in all fissures that may be allowing noise to enter a space.
Low Expansion Foam Has Less Moisture Absorption
Closed cell spray foam insulation’s rigid consistency allows it to have a lower moisture permeability rating compared to open cell spray foam insulation. Closed cell foam insulation works well in attics, most notably when applied to the underside of the roof deck, as it will prevent moisture from being transmitted.
Insulation R-Value
R-value measures the ability of a material to insulate and combat the flow of heat. The higher the R-value, the more effective the material is. Because of its density, closed cell foam insulation has a higher R-value than open cell foam insulation.
Price of Spray Foam Insulation Options:
Both types of insulation utilize a blowing agent to fashion the cells inside it. Water is the blowing agent for open cell insulation, whereas closed cell spray foam insulation uses chemicals in addition to water, adding to its expense. The density of closed cell spray foam insulation also means that more of the material must be used than if the same space was being insulated with open cell spray foam insulation.
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