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Open Cell Spray Foam vs Closed Cell Spray Foam: What’s The Difference?

Open Cell Spray Foam vs Closed Cell Spray Foam: What’s The Difference?

Energy Crisis is one of the hot-button topics around the internet today. A quick Google search will bring you face to face with stats and warnings about fossil fuels, renewable energy, and global warming. Regardless where you fall on the issue, as a member of the human race, we should be doing all that we can for the betterment of the Earth.

Saving the entire world might be a bit much to tackle today, but we can look at ways that a home or business owner can be more energy conscious. Energy Star (source: https://www.energystar.gov/)  states that the average home or business owner can reduce their energy consumption and save up to 15% on their heating and cooling costs by properly air sealing their structure. This is accomplished by adding proper insulation to the entire building envelope including attics, floors, walls, and roofs.

There are several options for insulation; however, Spray Polyurethane Foam (SPF) Insulation is quickly becoming more and more popular in both commercial and residential construction. The United States Environmental Protection Agency, or EPA (source: https://www.epa.gov/) , estimates that a home or business owner can save 20% of their heating and cooling costs and 10% of total energy costs by sealing their building with SPF.

Spray Foam Insulation

So, what exactly is SPF? Spray Foam Insulation consists of two liquids. On one side (A Side) you have methylene diphenyl diisocyanate (MDI) and polymeric methylene diphenyl diisocyanate (pMDI). On the other side (B Side), you have a unique blend of polyols, catalysts, blowing agents, flame retardants, and surfactant.

The two liquids remain separate, going through individual hoses all the way to the spray gun where they are mixed and applied to the surface of a structure as one liquid. As that liquid expands, it fills every crack and crevice in the surface of the structure. This is the process that creates a nearly impenetrable air barrier to any area that the spray foam is applied. (For example, the underside of the roof deck, the interior walls, and the building envelope.)

If you dig down deeper into the world of spray foam, you will find that there are two primary types of insulation: Open Cell Spray Foam and Closed Cell Spray Foam. Let’s take a more in-depth look at both of these spray foam insulation types.

Open Cell Spray Foam

Open cell spray foam is also known as half-pound foam. The half-pound refers to the 0.5 lb. density per cubic foot. Open cell spray foam typically has an R-value around 3.5 per inch. Open cell spray foam is air impermeable and reduces air leakage through the building envelope. However, because open cell is less dense, it may require a vapor retardant in colder climates.

Due to the lower density of open cell spray foam, it is the more economical option. Another advantage to open cell spray foam is flexibility. The open cells allow the foam to breathe and move with the shifting in the building. It is much less rigid than closed cell spray foam. Open cell spray foam is also good at absorbing sound.

You Should Consider Open Cell Spray Foam If:

• You are upgrading on a tight budget.
• You live in a warmer and drier climate zone.
• You need the insulation to be more flexible.
• You live where it is noisy outside.

Closed Cell Spray Foam

Closed cell spray foam is also known as two-pound foam. The two-pound refers to the 2.0 lb. density per cubic foot. Closed cell spray foam typically has an R-value around 6.5 per inch, nearly double the R-value per inch of open cell spray foam. Closed cell spray foam is also classified as air impermeable and can be used as an air-barrier. Since the cells in this spray foam are closed, it is also water-resistant and classified as a vapor retarder. This means, in any climate, there is no need for an additional vapor retardant.

While both spray foam insulation options will create a tight air-barrier, only closed cell spray foam will also create a vapor retarder. This is a massive bonus for more moist climates as this can help drastically reduce any water intrusion to the structure and virtually eliminates the possibility of mold forming. However, with the higher density of closed cell spray foam, the cost will be much higher per inch when compared to open cell spray foam.

Beyond this, closed cell spray foam adds a huge amount of structural strength, not only when applied to the inside of the perimeter walls, but also to the underside of the roof deck. In racking tests performed by NAHB Research Center where thousands of pounds of pressure were placed at the top corner of a studded wall panel, those panels that had closed cell spray foam sprayed in between the wall studs added two to three times the structural strength versus no closed cell spray foam installed. In a separate study a man by the name of David O. Prevatt also conducted some tests on closed cell spray foam. However these tests were performed on the underside of a roof deck. In his testing he found that closed cell spray foam increased the roof panel wind uplift capacity by 2.6 times over the same roof with no closed cell spray foam and withstood air pressures over 153 psf. In other words, it allowed the roof with closed cell installed to endure wind speeds equivalent to a Category 4 hurricane.

You Should Choose Closed Cell Spray Foam If:

• You want to add amazing structural strength to your home or building.
• You want an insulation that provides an air barrier, helps keep moisture out and is mold resistant.
• You want the highest R-value possible.
• You want the best product available regardless of cost.

If you are looking for a way to improve the efficiency of your home or business, then spray foam insulation should be the first item on your list. Now, hopefully, you will have a better understanding of what the two different types of spray foam insulations are capable of and make a more educated choice when it comes to upgrading your current structure or starting construction on a new one.

For additional information or any questions regarding spray foam insulation, please contact us at 817-533-6098