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How Do Crews Know if the Wall Cavity is Full When Injecting Foam Insulation?

injection foam insulation | Existing walls insulation | FAQ

How Do Crews Know if the Wall Cavity is Full When Injecting Foam Insulation? Blog Feature
Amanda Ringler

By: Amanda Ringler on June 8th, 2022

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Are you considering injection foam insulation for your exterior walls, but you are curious about how installers know when the cavity is full?

I know what you're thinking. You're wondering exactly how the installer knows when the injection foam insulation has filled the wall cavity when they can't see inside.

RetroFoam of Michigan has more than 20 years of experience installing spray and injection foam insulation in thousands of homes across the Lower Peninsula. Our crews are trained to ensure the cavity where the foam insulation is being installed is full, giving your home the coverage it needs to be more comfortable and energy-efficient.

So, how do the installers know when the wall is filled? Let's jump right into it.

Can Foam Insulation Be Installed in Existing Walls and Completely Fill the Cavity?

The quick answer is, yes.

Injection foam can be installed into an enclosed cavity, like exterior walls, without tearing down walls or waiting until your next remodel.

RetroFoam insulation has the consistency of shaving cream when it is injected. Because of its unique nature and composition, this allows the material to flow around any obstacles – water pipes and wiring – without getting caught up so it fills the entire cavity.

The process used by the RetroFoam installers also works to ensure the cavity is completely filled. Let's talk more about the installation process.

The Insulation Installation Process

Foam can be injected into existing walls without removing any existing fiberglass insulation.

If there is cellulose in the cavity, in some cases it may need to be vacuumed out, but usually, it can also stay right where it is.

In most cases, exterior walls can be insulated from the outside of the home. In rare cases, the installation may need to be done from the inside.

For the purpose of this article, let's talk first about aluminum and vinyl siding, then how the cavities are filled for walls with brick exterior.

Aluminum and Vinyl Siding Installation Process

For homes with aluminum or vinyl siding, a piece of siding is removed and a 2 1/2-inch hole is drilled into each stud cavity.

A crew member will run a Slim Jim up and down the cavity. This is done for several reasons:

  • To ensure there are no fire stops or no studs that will prohibit the hose from getting all the way to the top.
  • This is also done to feel for the next stud. This ensures the installer has a good idea of what is in the cavity from top to bottom and side to side.

The installer will then run the injection hose all the way to the top of the cavity and then all the way to the bottom. If the installer runs into any obstructions or blockages, another hole will be drilled either above or below it and more foam will be injected to ensure the cavity is completely filled.

Once the cavity has been completely filled, the holes are then plugged and the siding is replaced.

Brick Exterior Installation Process

How to install foam insulation in walls with brick exterior is quite different from vinyl or aluminum siding.

A 5/8-inch hole is drilled at the top, middle, and bottom of each stud cavity. This method ensures the cavity is completely filled with injection foam.

After the foam has been injected, the drilled holes are then filled with mortar.

Adding Injection Foam Insulation to Existing Walls

Once the work is completed, if at any time the homeowner feels an area has been missed, RetroFoam of Michigan has their back.

If a homeowner continues to feel a draft or problem area after we’ve installed the insulation, the crew will come out and do a thermal image scan to look for voids. If we find any missed areas, our lifetime warranty ensures we will re-fill any missed areas at no cost to the homeowner that same day.

If you would like to continue on your educational journey about spray and injection foam insulation, check out our Learning Center.

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Installing RetroFoam into Exterior Walls with Different Siding Types

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About Amanda Ringler

Amanda previously has worked as a breaking news and crime reporter, TV news producer, and editor in Flint and Detroit. Throughout her career as a journalist, she has won several awards from The Society of Professional Journalists - Detroit Chapter and the Michigan Press Association. As part of the RetroFoam of Michigan family, Amanda uses her experience as a journalist to write content that will help educate homeowners on the benefits of foam insulation. When Amanda isn’t writing, she’s spending time with her husband and rescued huskies. She also loves knitting, making art, cooking, and hosting dinner and a movie night for friends and family.