Spray Foam vs Rigid Foam Insulation: The Differences That Matter

Whether you plan to build a home or an office, one must think about insulating it. Insulating a building helps it maintain a constant temperature even in harsh conditions like extreme cold or heat. Gone are when there were only limited options for insulating one’s home.

Now, with the onset of advances in polymer technology and versatile insulation solutions, there are many options for customers to choose from. However, every home resolution has its merits and demerits over the others and needs to be considered carefully to make an informed decision.

There has been extensive use of foam insulation for new construction and re-insulation projects. There are different types of foam insulation available in the market for different budget preferences.

This article will explore the differences between some of the best foam insulation methods; spray foam insulation and rigid foam insulation. The article will cover an in-depth analysis of spray foam and rigid foam and compare them to provide the reader with enough evidence to make an informed decision.

Spray Foam vs Rigid Foam Insulation

What is the Difference Between Spray Foam and Rigid Foam Insulation?

Even though most use cases of spray foam and rigid foam are common, there are many potential differences, right from installation, to the type of air infiltration, budget, etc. Consumers have to be aware of all facts to prefer one over the other for tackling a specific problem efficiently and economically.

Spray foam insulation is a special type of insulation where two components are mixed and then applied to the surface that needs to be insulated. However, rigid foam panels are available in usable conditions from stores and don’t require a professional hand for installation.

Foam insulations are essential in blocking sounds, adding more mass to the surface, increasing heat and fire resistance, reducing impact and airborne noise, etc.

Spray Foam

Rigid Foam

Spray Foam materials are mostly made from polymers such as polyurethane or polyisocyanurate.

Rigid foam is often made out of polystyrene polymers and is way more available and prevalent in use.

This type of foam is applied wet onto the desired surface, and once it dries, the foam expands and settles onto the surface.

These are available in many stores and are more popular than spray foam insulation methods. It is available in pre-made condition and can be cut into desired shape and size for placing it onto the surface.

Spray Foam is mainly used in places that are hard to reach by conventional insulation methods. Since spray foam can be sprayed into corners and cracks on the surface, it provides a good fit and excellent insulation than most solutions.

Rigid foams are used in relatively new construction projects. Rigid foams are perfect for projects with unfinished walls and can be used effectively and economically in most cases.

Spray Foam can reach hard-to-reach surfaces, cracks, and crevices, providing air sealing to the surface.

On the other hand, Rigid foams are ready-made materials and don’t necessarily provide the perfect fit for the surface. Therefore, they provide poor air sealing to the surface.

Another factor to consider while looking for insulation solutions for your home is the R-value. The R-Value is an indicator of the ability of the material to resist the flow of heat through it. It can be seen that there can be differences in the R-value of both spray foam and rigid foam.

R-Value of rigid foams typically ranges between 3.8 to 5.0 per inch of the material. On the other hand, polyurethane spray foam can have an R-value of 5.5 to 6.5. This is very important and should be considered while opting for insulation material.

Spray Foam Insulation

Spray Foam Insulation

The use of Spray Foam insulation is rapidly on the rise due to its versatility and its properties. Spray foam can be directly sprayed into vanities, attics, corners, etc., and it can insulate all types of open cavities and hence is a powerful solution. Another advantage of using spray foam over other traditional methods is its ease and guaranteed results.

Spray foams won’t lose shape and texture during installation or after it, and it settles permanently and is guaranteed not to compress and lose their properties over time. If you have to pay high amounts of bills to keep your home warm and struggle to maintain a constant temperature throughout the year, spray foam is the perfect solution for you.

The air seal it creates upon installation will help keep the warm air inside, thereby regulating the room’s temperature.

Now, let us look at the pros and cons of spray foam insulation in detail.


  • Spray foam insulation is a versatile energy-saving solution.
  • If adequately applied, spray foam can stick onto the surface and fill all open gaps, cracks, crevices, etc.
  • Spray foam is resistant to mold and mildew. It restricts the passage of air and can block out moisture content. Thus, condensation doesn’t happen, so molds and mildews can’t form on the surface.
  • Spray foams are materials with high R-Value and thus reduce energy bills.


  • Spray foam, in general, tends to be more expensive than rigid foam insulation. Studies have shown that spray foam insulation can cost over three times the cost of rigid foam insulation for the same surface area.
  • The effectiveness of spray foam insulation is mainly dependent on the method rather than the material, and it takes a professional set of hands to apply it effectively.

Spray foam is an effective solution for re-insulation of old homes, as they require a higher level of care to cover every corner. However, spray foam insulation is a costly solution and should be considered only after correctly estimating the budget.

Rigid Foam Insulation

Rigid Foam Insulation

Rigid foam insulation is somewhat conventional and is available pre-made at stores. They can be bought according to requirements and can be cut to fit the size and shape of the surface to be insulated.


  • Rigid foam has a relatively high R-Value and has good insulation properties.
  • They are less costly than spray foam and are convenient and economical.
  • Rigid foams can provide strength to the existing walls due to the structure and method of installation.


  • Rigid foam insulation is comparatively less efficient than spray foam.
  • Rigid foam insulation has limited options as it needs to be installed inside an open, exposed wall.

The installation of Rigid foam insulation doesn’t guarantee the efficiency of spray foam due to its structure. They are more rigid and can even provide structural support to the surface it is placed on. They are best suited for unfinished walls, and their installation needs to be planned early on.

Spray Foam Insulation vs Rigid Foam Insulation: Head-To-Head Comparison

Rigid foam insulation and spray foam insulation are effective solutions for energy conservation at home. But, they are different in many aspects, and this can be used to one’s advantage while insulating a surface.

Let us compare the most important aspects of both insulations and arrive at a conclusion for consumers to make an informed decision.

Types of Project

Rigid Foam Insulation: It is often used for new construction projects and is best suited for surfaces with unfinished walls.

Spray Foam Insulation: It is used to insulate hard-to-reach surfaces, including cracks, crevices, gaps, etc.

Air Infiltration

Spray Foam Insulation: It can reach all open gaps existing on a surface and provide an air seal to it. Air leaks are crucial in driving up energy prices, and rigid foams are not as effective as spray foams in preserving the heat.

Rigid Foam Insulation: Since these are available as panels, it doesn’t necessarily guarantee air sealing and hence provides comparatively, poor air infiltration.


R-Values are essential factors that can give you a good idea about the ability of a material to insulate a surface.

Rigid Foam Insulation: It can provide an R-value from 3.8 to 5.0.

Spray Foam Insulation: It can provide anywhere upto 5.5. -6.5 according to the method of installation.


Spray Foam Insulation: It costs about three times more than rigid foam insulation for the same surface area. This is due to the change in technology and the labor cost required to operate and apply spray foam insulation.

Rigid Foam Insulation: It is cheaper of the two and can be considered for ongoing projects with unfinished walls for better cost effectiveness.

What Is Better Spray Foam Insulation or Rigid Foam Insulation?

Spray foam insulation and rigid foam insulation are sophisticated energy conservation solutions and can be intelligently used for different scenarios.

  • We have seen that spray foams can be applied over any surface, and they will adhere to it once it settles. This makes it perfect for re-insulation in old homes with many irregular surfaces and cracks, gaps, and crevices.
  • Rigid foams are best suited for the freshly undergoing construction process, with unfinished walls. This makes it easier to place the rigid foam panels on the walls and provide structural support and thermal insulation.

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Final Words

This article has laid down all the facts regarding rigid foam and spray foam insulation. They are versatile solutions and need to be applied to different use cases.

One needs to be informed about all the merits and demerits of both materials to make important decisions that can be both effective and economical at the same time.

You can also be aware of the shortcomings of each method and know what to expect along with the benefits of each material.

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