In the construction industry, SPF is a versatile and innovative insulation material that is becoming increasingly popular. It offers superior insulation and air-sealing capabilities, making it a great choice for energy-efficient and sustainable buildings. In this article, we will explore the different types of SPF, its applications, and why it is more than just an insulation material.

Table of Contents

What is Sprayed Polyurethane Foam (SPF)?

Sprayed Polyurethane Foam (SPF) is a high-performance insulation material created by mixing two liquid components and spraying them onto a surface. The foam expands and adheres to the substrate, forming a solid, seamless, and insulating layer that seals gaps and voids, providing an airtight and moisture-resistant barrier.

Types of SPF: Versatility and Applications

As insulation properties, SPF can be used in a wide range of applications, with the choice of SPF type depending on the specific requirements of the project.

For interior insulation, open-cell SPF is the preferred option. It is characterized by tiny cells that are not completely sealed, allowing controlled air infiltration. Its lower density and flexibility make it an excellent choice when moisture control and air sealing are vital.

However, it’s important to note that while open-cell SPF can assist in moisture control by allowing some moisture diffusion, it may not be suitable for areas with a high risk of continuous water exposure.

In contrast, closed-cell SPF offers higher density and rigidity due to its entirely sealed cells. This impermeable quality makes it the top choice for applications requiring robust insulation and resilience against external elements, including moisture-resistant barriers. Consequently, closed-cell SPF is commonly employed for roofing materials, exterior insulation projects, and soundproofing endeavors.

Installation Process of Sprayed Polyurethane Foam (SPF)

The installation process of Sprayed Polyurethane Foam (SPF) is a crucial phase that determines the effectiveness and longevity of the insulation or sealing job. Here are the details of the SPF installation process:


  • Inspection

The surface inspection is an important step in the preparation process. The installer should look for any dirt, debris, oil, or other contaminants that could interfere with the adhesion of the SPF. If any of these are present, they must be removed before the SPF can be applied.

  • Protection

Once the surface has been inspected and cleaned, any areas that should not receive SPF must be covered and protected. This includes windows, doors, fixtures, and any other areas where overspray could be a problem. The installer should use a tarp or other protective material to cover these areas.

  • Safety Measures

Safety is always important, but it is especially important during SPF installation. The installer must wear appropriate personal protective equipment (PPE), including a respirator and protective clothing, to protect themselves from exposure to SPF chemicals. The PPE will help to prevent the installer from inhaling or coming into contact with the chemicals, which can be harmful.

Spraying Process

  • Mixing

The spraying process of SPF is a crucial step in the installation process. It begins with the precise mixing of the two liquid components: isocyanate and polyol. The amount of SPF applied will vary depending on the specific application.

  • Application Equipment

Once the mixture is prepared, it is applied to the target surface using specialized spray equipment. The spray equipment uses a nozzle to atomize the foam, which ensures that it is evenly distributed over the target surface.

  • Spraying Technique

Skilled installers apply the SPF mixture methodically, moving the spray gun in a consistent pattern to ensure uniform coverage. They start from the bottom and work their way up, maintaining a consistent thickness.

It is important to ensure that the foam is applied evenly and that there are no gaps or voids. Once the SPF has been applied, it will expand and solidify, forming a solid, continuous layer that adheres to the substrate.


  • Expansion

After the SPF mixture comes into contact with the surface, it begins to expand rapidly. This expansion is crucial for the SPF to fill voids, gaps, and crevices, ensuring that no areas are left uninsulated. The expansion usually takes place within a few minutes, but it can vary depending on the environmental conditions, such as temperature and humidity. Once the expansion is complete, the SPF begins to solidify.

  • Solidification

SPF typically solidifies within a few hours, depending on the environmental conditions. During this phase, the foam becomes a solid, continuous layer that adheres firmly to the substrate, ensuring that the foam is durable and long-lasting.

Trimming and Shaping

Once the SPF has cured, it may need to be trimmed and shaped to achieve the desired finish. This is done by carefully cutting away any excess foam that has expanded beyond the desired boundary. This step ensures a neat appearance and allows for any subsequent surface treatments or coatings.

Final Inspection

A final inspection is conducted before the job is considered complete. This inspection ensures that the SPF has been installed correctly, with uniform coverage and adhesion. Any areas that need touch-ups or additional attention are addressed during this phase.


Sprayed Polyurethane Foam (SPF) has redefined insulation and sealing in construction. Its ability to provide superior insulation, air sealing, and moisture resistance has made it a top choice for energy-efficient and sustainable buildings.

SPF is also available in a variety of types, so it can be used for a wide range of applications, such as roofing, walls, and floors. As the construction industry continues to evolve, SPF will likely remain a key player in achieving comfort, efficiency, and durability.

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