Spray Foam vs. Injection Foam: What's The Difference For Homeowners?

As you’ve done your research on spray foam, you came across the term injection foam. Are spray foam and injection foam different products, or are those terms used interchangeably? If they’re different products, when should they be used?

South Central Services has insulated hundreds of homes with spray foam insulation. Our job is to educate our customers about their insulation options and what those options can offer them. Whether we install an insulation product or not, customers should know if that insulation is an option and whether it can benefit them.

By the end of this article, you should have a better idea of whether spray foam or injection foam insulation would work for your project. Specifically, you will know:

• How spray foam and injection foam are similar
• What’s different about spray foam and injection foam
• What each type of foam is best used for

Don't have time to read right now? Check out everything you need to know at a glance.

Similarities Between Spray Foam And Injection Foam

Both spray foam and injection foam are formulated for insulation purposes. Spray and injection foams should have the necessary R-values and have passed rigorous testing for fire safety. Contractors who install these foams have rigs with expensive equipment for application.

Whether you choose spray foam or injection foam, you should hire a professional contractor to complete the installation. Spray foam insulation technically sells DIY kits, but the product is complex enough to warrant hiring a professional. Injection foam is unavailable as a DIY, so you must hire a contractor to install injection foam in your home.

Differences Between Spray Foam and Injection Foam

Spray foam and injection foam insulation are different products with different applications. Which product would be best for your project will depend on what you are insulating and what performance you are looking for. These are the critical differences between spray foam and injection foam.

1. Foam ingredients
2. Installation methods
3. Ideal applications

Let’s examine the differences between these foam insulations in more detail.

1. Spray Foam And Injection Foam Have Different Ingredients

Spray foam insulation is a two-component foam, while injection foam is a three-component product. Spray foam is created by mixing two chemicals in an equal ratio, which causes an exothermic chemical reaction. Injection foam is made by mixing resin, water, and a foaming agent.

Spray foam insulation will expand in place, while injection foam has the consistency of shaving cream and does not expand.

2. Spray Foam And Injection Foam Are Installed Differently

Professional contractors install spray foam with a spray hose and spray gun. The raw materials come in 55-gallon drums and are prepared with a proportioner. The proportioner keeps the raw materials on-ratio and heats the chemicals to the appropriate temperature for the chemical reaction. Contractors run their heated spray hose from their rig to the application site.

When professional contractors install injection foam, they access exterior walls from the outside of a home and pump foam into those walls. Some homeowners do not want their exterior walls to be drilled into. In these cases, injection foam can also be installed from inside the home. Injection foam is a mixture of resin, foaming agent, and water. After mixing these materials, the foam is pumped through hoses into holes drilled into the wall.

3. Spray Foam And Injection Foam Solve Different Insulation Problems

Spray foam insulation is a versatile insulation. Between its two varieties of open cell and closed cell, spray foam can be installed in attics, roofs, exterior walls, basements, crawl spaces, and underslab. Spray foam can also be used for commercial applications. There are numerous substrates that spray foam insulation can adhere to.

Injection foam insulation is a product specifically designed for retrofitting existing buildings. With its shaving cream consistency, this foam can be pumped into existing walls at whatever quantity is necessary to fill the cavity. Injection foam cannot be used in new construction wall cavities.

The Bottom Line About Injection Foam And Spray Foam

Spray foam and injection foam are different insulation products designed for different applications. If you need minimally-invasive foam insulation for your retrofit project, injection foam is your solution. If you have a broader scope of needs, such as a crawl space, basement wall, or attic, spray foam insulation will offer the performance you’re looking for.

Now that you know the difference between injection foam and spray foam, next you should:

• Learn the difference between open cell and closed cell spray foam
• Discover if there are any problems with spray foam insulation
• Find out why spray foam insulation is best