Difference Between Open-Cell and Closed-Cell Spray Foam Insulation

The Difference Between Open-Cell and Closed-Cell Spray Foam Insulation

The Difference Between Open-Cell and Closed-Cell Spray Foam Insulation

Sometimes it is very hard to decide what type of spray foam insulation you should use for your home. We know that’s trickier than it seems – though closed cell and open cell foam both insulate a home, they do it in different ways. But luckily for you, Eco Spray Insulation has all the experience and our professional experts will help you out to decide which is the best for you.

What’s the Difference Between Open Cell and Closed Cell Foam Insulation?

Open and closed cell foam are two different types of spray foam insulation. They have different strengths and weaknesses, and one is not necessarily better than the other. It comes down to understanding the benefits of open cell vs closed cell foam and choosing the type that fits your needs.

Let’s see the differences between open and closed cell foams.

The Cells

A spray insulation is referred to as an open cell or closed cell because of the difference between the small bubbles (cells) that make up the foam.

Open cell foam is full of cells that aren’t completely encapsulated. In other words, the cells are deliberately left open. This makes the foam a softer, more flexible material. Those tiny cells which are not completely closed are filled with air and this affects the way the foam feels and performs. With our equipment and skills, you will be pleased and won’t regret that you chose us.

Closed cell foam is made up of cells that are, as the name suggests, completely closed. The cells are pressed together, so air and moisture are unable to get inside the foam. Because of this, closed cell foam is much more rigid and stable than open cell foam. Closed cell foam has cells that are sealed off so air doesn’t get inside the structure at all.


Closed cell foam is much denser than open cell foam. Most open cell foam has a density of about .5 pounds per cubic foot. Closed cell foam can be over three times that, with a density of  1.75 pounds per cubic foot or more. The major difference between the two foam options is that closed cell foam tends to be harder or firmer while open cell foam is softer or less firm.

The quality and prices that Eco Spray offers are the best in the market so you will have the best insulation for your home.


A foams R-value is its resistance to heat flow or, in other words, how well they insulate.

Closed cell foam has a higher R-value than open cell foam, usually about 6.0 per inch. But some closed cell foams, like Tiger Foam’s E84 Closed Cell formula, have even higher ratings that go up to almost 7 per inch. This higher rating makes closed cell foam better at keeping the heat in or out of a structure.

Open cell foams have an R-value of around 3.5 per inch. This is significantly lower than closed cell foams, which can limit open cell insulations usefulness in extreme temperature conditions.


This is one of the most important differences from an application standpoint. Closed cell foam is designed to expand to about 1″ of thickness when sprayed. With each inch offering an r-value of 7, multiple applications can be applied to achieve higher total r-values. Open cell foam is designed to expand to 3″ of thickness, meaning only one application is possible in most standard walls.


There are several applications for foam with one or other type of cell structures being more ideal. Since a closed cell is incapable of holding water to make a cushion heavier and harder to dry out, it is often used in outdoor cushions. Closed cells are also used for various purposes where a sturdier structure is needed such as packaging and shipping needs, protection barriers, and more. This type of foam can be used in construction as building insulation since it creates a nice barrier to trap heat and air conditioning inside a building to reduce utility costs. It can also be used for certain electrical and automotive applications as long as it stays clear of heat.

Open cell foam is softer and springier, this foam type offers superior comfort and support for a range of applications. With the superior comfort it offers, it is no wonder open cell is used in all manner of sofas, chairs, loveseats, and mattresses. Available in varying levels of firmness and density, open cell foam can be super soft or firmer for more support. It can be used in support aids, pillows, pet beds, and much more. Our team will provide the proper installation of this product.

Durability factor

While closed cell foam is generally stronger and longer lasting than open cell foam, both options offer lasting durability. Closed cell is tougher since it provides improved rigidity. It is also tougher in terms of rips or tears whereas open cell foam is more vulnerable to surface damage. Our experts know what’s the best for your building and while installing the product, you can be sure about the strength of the structure.

Application methods

Closed-cell foams sprayed to a certain depth create their own vapor barriers; open-cell foams typically require vapor barriers in the tradition of fiberglass and other batt-type insulations. In general, closed-cell foams require an open stud bay for their application and are thus not particularly suited to retrofit unless existing walls are first removed. Certain slowly-expanding, open-cell foams are available for through-the-wall filling of existing wall cavities.

The components are often routed through heaters before being mixed and dispensed at high pressure to partly or completely fill the spaces between studs, joists, and rafters. Such two-part systems include the “A” part – usually a combination of methylene diphenyl diisocyanate (MDI) and polymeric MDI – and the “B” part, usually, a blend of polyols, catalysts, blowing agents, flame retardants, and surfactants. 

Many people think that the cell structure of the foam is related to thickness variations. However, both open and closed cell foam is available in varying degrees of thickness. The thickness needed will depend on the application. While both types of foam structures can be used in varying thicknesses, open cell foam can lose the springy nature of the material when used in options too thick, and closed cells can be less sturdy in thinner cuts as opposed to thicker ones.

When choosing between the two, the types of applications, as well as the desired results, will be the main determining factor in which type is more suitable. Both options are known to offer the lasting endurance and high levels of performance expected of this versatile material.

Benefits of Closed/Open Cell Foam?

At this point, you might be still trying to decipher which type of foam insulation is right for your project. Here’s a quick summary of open cell vs closed cell foam strengths and the best applications for each:

Benefits of Closed Cell Foam

Closed cell foam is the best choice for robust insulating where space is an issue, as it can achieve 2x the R-Value of  open cells inside a standard wall. Its rigid nature also adds to the structural integrity of the building and E84 fire rated versions are available. The closed cell also acts as a vapor barrier, so water and moisture will be less likely to get inside the home, and the foam itself is unharmed by water damage.

Benefits of Open Cell Foam

One of the biggest benefits of open cell foam is that it expands so much after it has been applied, meaning it can insulate hard to reach nooks and crannies in a home. These types of areas can be hard to insulate with closed cell foam. Open cell foam is excellent for soundproofing where a single application can completely fill the area between studs.

Open cell foam is also much more affordable than closed cell foam, however this foam won’t insulate a house as well as closed cell foam, so it’s not ideal for locations with extreme weather temperatures.

Installing spray-on foams involves the use of chemical resins and blowing agents necessitating the need for personal protective equipment. Building codes generally require a thermal and/or ignition barrier between the foam and occupied spaces and there are a variety of flame-resistant foams available. Burning foam can release many toxic vapors.

The foam will surround everything in the wall cavity including pipes, wires, junction boxes, etc. Care must be taken during installation to be sure that the foam does not enter electrical spaces or coat surfaces where it is unwanted. Foam can make later electrical and plumbing repairs difficult.

If you still have doubts about what kind of spray foam you should use for your home, just give us a call and we will give you the best choice. Eco Spray Insulation will provide you quality service, professional experts and you will be pleased for every single penny that you invested.

Open Cell and Closed Cell Spray Foam Insulation 1

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