TAMPA CENTRAL Blog

Understanding the Difference Between Closed Cell vs Open Cell Foam

Spray foam insulation is undoubtedly a great choice for insulating your home. However, people often get confused about closed cell vs open cell foam. Foam insulation is excellent for reducing heat flow, making your home better insulated to give comfort and cut down utility bills. On top of that, these insulations can potentially increase the value of your house. 

Both open cell and closed cell sprays are widely used. However, there’re significant differences between them regarding their physical structures, efficiency, application, and insulation. In this article, we'll discuss their differences and characteristics, so you can make a well-informed decision accordingly. 

Closed Cell vs Open Cell Foam

Closed cell foam, as its name suggests, is composed of tightly packed cells that don't leave any space for heat or airflow. It has a high R-value, which is a material's capacity to resist airflow and insulate a building. Closed cell spray can offer better moisture resistance thanks to its higher R-value. It’s a dense material that helps insulate the air both inside and outside the material, preventing mold growth.

Open cell spray foam doesn't pack as tightly as closed cell spray foam and spreads as soon as it’s applied. Therefore, it’s a great option for tight spaces where closed cell spray foam can't cover the area. It has a lower R-value than closed cell spray foam, from 3.6 to 3.8 per inch. Since it isn't as tight as closed foam and has a lower R-value, it is more permeable.

Let's now discuss the differences between the two foams in detail to help you make a clear choice.

Structure 

When we talk about closed cell vs open cell foam, the first thing that comes to mind is their structures. Closed cell spray foam is denser at 1.75 to 2.25 lbs. per cubic ft. Its closed cells resist air and water, making a durable cover that isn't easily damaged even after constant exposure. Also, it doesn't expand after application, making it more rigid and long-lasting.

Open cell spray foam expands rapidly after application and forms a bubble-like structure. This expansion makes it more pliable, lighter, and flexible. It is a better choice when you want to reach tighter spaces and is also much easier to remove.

Moisture Absorption 

The packed structure of close spray foam doesn't let water travel back and forth, resisting moisture effectively. However, it can have the downside of concealing a leak that can result in a water buildup. The buildup isn't noticed quickly, which can result in bigger damages later on.

Open cell spray foam allows the movement of water but still doesn't let the mold grow because it's inorganic. After getting dry, it gives a path for the water to move in and out. High-quality open cell spray foams can hold 5% to 70% of their weight in water. However, that makes them a bad choice for areas with high humidity. If you live in a high-humidity area but still want to use open cell spray, use vapor-retardant spray over it to tackle the issue of moisture.

Sound Absorption 

Closed cell spray isn't very good at absorbing sounds because of the very little space it offers to sound waves. Its hard surface simply reflects the sounds of a drum skin.

On the other hand, open spray foam is excellent at absorbing sounds. Thanks to its structure, it offers the air inside its little spaces where air keeps floating and bounces back & forth. As a result, it gets absorbed in those spaces, and we hardly hear it.

Durability 

Usually, closed cell spray foam is stronger because it offers improved rigidity. It is also tougher and offers exceptional resistance to wear and tear. On the other hand, open cell foam spray is lighter and less rigid. 

R-Value 

R-value of closed cell vs open cell foam is also a critical consideration. With a high R-value of over 5.5 per inch, closed cell spray foam absorbs twice the heat compared to open cell spray foam. Those residing in areas with extreme heat and humidity can greatly benefit from it. Open cell spray foam has a much smaller R-value of 3.5 to 3.8 per inch, which makes it absorb much less heat.

Cost 

Sometimes, the cost is the ultimate deciding factor in choosing between closed cell vs open cell foam. The closed cell spray foam is expensive because it doesn't expand after application, requiring more material to cover an area. In contrast, open cell spray foam expands as soon as it is applied. It means you need to apply less of it, saving you a significant chunk of money.

Pros & Cons of Closed Cell vs Open Cell Insulation

As of now, you know all the significant differences between them, let’s discuss the pros and cons of closed cell vs open cell insulation; 

Pros & Cons of Closed Cell Foam Insulation

Pros

• Best for insulating places where space is an issue
• Has double the R-value of open cell spray foam insulation
• Its rigidity adds to the structural strength of the building 
• E84-rated versions are available for enhanced fired safety 
• Offers a robust water barrier, keeping moisture under control

Cons 

• Higher density and more rigidity can lead to breakages 
• Low breathability due to a tightly packed structure 

Pros & Cons of Open Cell Spray Foam Insulation 

Pros

• It is lightweight, weighing from 1.2 lbs per cubic foot to 2.6 lbs per cubic foot
• Flexible enough to contract or expand during cold and hot weather 
• Some forms are designed to retain very little moisture despite their open structure 
• Great for dampening sound waves

Cons

• Not suitable for places with extreme temperatures because of its lower R-value
• Due to its low density, it doesn't provide enough rigidity and structural support
• It can shrink over time, depending on the conditions 

Conclusion 

The choice of closed cell vs open cell foam depends upon several factors. If you're in an area that demands higher R-value insulation on its building, you'll need closed-cell spray foam insulation. On the other hand, if you are after saving costs, open cell spray foam is a much better choice. It takes less material and labor costs.

If you're looking for a reliable & efficient insulation service, look no further than Koala Insulation. Koala provides residential, industrial, and commercial insulation at competitive rates. The SPF insulation reduces noise, stops air leaks, controls humidity, and lowers your energy bills.