Essential Tips for Buying RetroFoam Insulation

Everything you need to know about buying RetroFoam insulation for your existing walls.

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Buying Insulation for Your Existing Walls Isn't Something You Want to Rush Into

There is a lot to consider and think about before you take the plunge.

Things like, will the insulation stop drafts from getting into your home? Does the material need to be maintained over time and eventually replaced? Will it help lower monthly energy bills? Can the insulation make the rooms in the home more comfortable?

If you’ve landed on RetroFoam injection foam insulation for your existing walls, those are issues you won’t need to worry about anymore.

Everything You Need to Know About RetroFoam

Here in this guide, you will find answers to all of your questions regarding RetroFoam injection foam insulation for your existing walls. We’ll cover the signs it’s time to update your exterior wall insulation, the pros and cons of RetroFoam, what factors determine the cost, and a whole lot more.

This guide was created with you, the homeowner, in mind to answer all of your questions. So, sit back and enjoy the ride while we break down everything you need to know about RetroFoam insulation.

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Signs it’s Time to Consider Insulating Existing Walls


You could be experiencing several issues in your home due to little or no insulation in your exterior walls, and some of them you may not even realize are connected.

It might be hard to tell whether your walls have any insulation at all, but a quick look behind an outlet cover or light switch can at least give you an idea of what you’re working with.

The non-visual signs you need to update your existing wall insulation can be very annoying, especially if you’re dealing with comfort and even health issues related to it.

Let’s dive right into these issues and talk about how RetroFoam insulation can help.


Signs You May Have Issues with Your Existing Wall Insulation

Your Monthly Energy Bills are Consistently High

You Deal with Uncomfortable Rooms Year-Round

Your Furnace and Air Conditioner Never Take a Break

Noticeable Drafts Coming From Electrical Outlets and Light Switches

Condensation and Mold on the Walls

Walls are Cold to the Touch

Dishes are Ice Cold

Existing Wall Insulation is More Than 15-Years-Old

Critters Have Turned Your Wall Insulation into Condos

Allergies are Becoming an Issue Inside the Home

Updating Your Existing Wall Insulation


If you are experiencing any of the above issues, it’s time to update the insulation in your exterior walls.

Adding RetroFoam injection foam insulation to your existing walls can address and fix the signs and symptoms we just talked about. The foam insulation does this because it creates an air seal that isn’t possible with traditional insulation.

This air seal works to make your home healthier, more comfortable, and energy-efficient.

But now you’re probably wondering, “what is RetroFoam?” Keep reading. We’ve got the answers.

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What is RetroFoam?


What is RetroFoam?

RetroFoam is an injection foam insulation that is used for existing exterior walls and concrete block walls.

Injection foam insulation, like RetroFoam, is best suited for enclosed wall cavities and can be installed from the outside, so there is no need to tear down your drywall.

RetroFoam insulation is Class One Fire Rated, which means if there were a fire in your home, it doesn’t act as a catalyst. Once the flame is removed, the foam will self-extinguish.

RetroFoam also doesn’t off-gas, is environmentally friendly, and is safe to have in your home.

In your research, you might have noticed some contractors using the phrase “spray foam insulation in existing walls” to describe injection foam. We will dive deeper into the difference between the two in just a little bit.


What is RetroFoam Made Of?

RetroFoam is a tripolymer based resin that creates odor-free, non-toxic foam insulation.

This resin is mixed with water and a foaming agent in the RetroFoam installer’s trailer. Once it’s mixed, the final product looks a lot like shaving cream and even has the same consistency. 

It’s that shaving cream consistency that helps RetroFoam insulation completely fill the cavity, getting into all of the nooks and crannies, as well as spreading around wires and pipes in the wall.

Is RetroFoam Insulation Safe to Have in the Home?


RetroFoam is absolutely safe to have in your home. 

RetroFoam insulation doesn’t off-gas, is Class One Fire Rated, and is environmentally friendly.

There is a lot of misinformation about foam insulation and whether it’s safe, so let’s clear that up to ease any concerns you might have.

Does RetroFoam Off-Gas?

Off-gassing is more of a concern when it comes to spray foam insulation. 

That off-gassing, or volatile organic compounds, are little bits that are expelled when the foam is sprayed. Hairspray, body spray, and even your dry cleaning technically off-gas.

Injection foam insulation, more specifically RetroFoam, doesn’t have any off-gassing at all.

Is RetroFoam Insulation Flammable?

RetroFoam home insulation is Class One Fire Rated, which means it doesn’t act as a catalyst if there were a fire in your home.

Once the fire is extinguished or the flame is removed, RetroFoam will self-extinguish.

Let’s talk a little bit more about what that fire rating means.

The fire rating system for insulation is basically how long the material can withstand a standard fire resistance test.

A Class One Fire Rating really means the flame spread and smoke development index, or how fast the flame will spread in the insulation and how much smoke it produces.

To get this Class One Fire Rating, the insulation must have a smoke development of less than 450 and a flame spread index of 25 or less.


Does RetroFoam Injection Foam Contain Formaldehyde?


The word formaldehyde can be very scary, especially when it comes to your home.

Something to keep in mind -- you already have formaldehyde in your home in places you would never have thought about.

Tobacco smoke, cosmetics, lotions, shampoo, conditioner, shower gel, keratin hair smoothing treatments, and some fingernail polish all contain some level of formaldehyde, according to the American Cancer Society.

Other things that have trace amounts of formaldehyde are crafters glue, caulk, drywall adhesive, some insulation boards, and some liquid detergents, according to the U.S. Department of Health and Human Services.

Now that you know about all the things with formaldehyde in them, let’s talk about that RetroFoam formaldehyde content.

RetroFoam injection foam insulation has a trace amount of formaldehyde present in the dry product at 0.06 parts per million, but it bonds to the material when it is mixed in the installer’s truck. This means the finished RetroFoam product in your walls is classified as formaldehyde-free because it can't escape that bonding.

How Does RetroFoam Insulation Work?


RetroFoam injection foam is an energy-efficient insulation that creates an air seal in enclosed cavities.

Unlike traditional insulation, RetroFoam never loses its shape, and it won’t settle, compress, shift, or sag as time goes on.

The insulation you have in your walls should help your home maintain a constant temperature without putting an unnecessary strain on your AC unit and furnace. This is why the air seal created by RetroFoam makes it an energy-efficient foam insulation that works to lower your heating and cooling costs.

When energy-efficient wall insulation does its job, it affects the conduction (heat transfer) and the convection (airflow), which are huge factors in your home’s performance. The air seal created by RetroFoam insulation reduces air leakage and also provides heat resistance.

We’ve told you about all of the pros of RetroFoam insulation, but it wouldn’t be very transparent if we didn’t talk about the cons as well.

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The Pros and Cons of RetroFoam Insulation

All Insulation Materials Have Their Own Set of Pros and Cons


In being transparent, here is a full look at the good and potentially not-so-good pros and cons of RetroFoam insulation.

RetroFoam Insulation Pros

  • RetroFoam injection foam insulation creates an air seal that stops airflow into and out of your home.
  • Injection foam insulation, like RetroFoam, can reduce noise transmission into your home with its sound dampening properties.
  • Insulating exterior walls can help reduce the number of allergens and pollutants in your home.
  • RetroFoam insulation can actually pay you back with the money you save on monthly energy bills.
  • Injection foam can help combat condensation caused by extreme temperature differences from forming on your exterior walls.

RetroFoam Insulation Cons

  • While rare, there is the possibility that the injection foam could bow or crack your drywall.
  • If there is a missed fire stop in the wall, there is the possibility the cavity won’t be completely filled.
  • RetroFoam insulation is a more expensive option compared to traditional insulation.
  • In some cases, if there is glued in cellulose in your wall cavities, it may not be possible to inject the foam because the hardened material will block it.
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Who isn’t a Good Fit for RetroFoam Home Insulation

RetroFoam Isn't For Everyone


Sometimes it just isn’t meant to be, and we get it.

There are several reasons why RetroFoam insulation might not be a good fit for you.

  • This isn’t your forever home.
  • You rent the home you want to insulate.
  • Your home insulation is already adequate.
  • Energy efficiency isn’t important to you.
  • You’re looking for a cheap home insulation option.
  • Your home isn’t built for injection foam insulation.
  • You only want to insulate the attic, crawl space, or rim joist.
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What is the Difference Between RetroFoam Injection Foam Insulation and Spray Foam Insulation?

Injection Foam vs. Spray Foam


Some homeowners run into some confusion when researching home insulation because there are contractors who use spray foam and injection foam interchangeably.

While the two create an air seal and make homes more energy-efficient and comfortable, there are some differences. The biggest difference between spray foam insulation and injection foam insulation is really how they are installed and where.

RetroFoam injection foam insulation is used in enclosed cavities, like existing walls and concrete block walls. It is installed from outside of the home but can be done from the inside in certain situations.

The home’s exterior can change the installation process, but we’ll get more into that in a few minutes.

Another thing to note for injection foam is that the old fiberglass in the walls doesn’t need to be removed. If there is cellulose, the installer will try to remove as much of it as possible before injecting the foam. This is done because cellulose won’t compress in the wall cavity the way that fiberglass does, so in some instances, it can act as a barrier in the wall, so the foam doesn’t completely fill it.

Spray foam insulation is better suited for open spaces, like the attic roof deck or flat, crawl space, rim joist, or exposed walls.

Before the spray foam can be applied, all of the old insulation in the space must first be removed. This is because the spray foam needs a clean surface to adhere to. 

Another measure the installers take before the spray foam is applied is to prep the area. This means any furniture or other items should be moved out of the area or to the room’s center. The installer will then cover everything in plastic, including the floors and surfaces like countertops or railings. This is done to ensure spray foam doesn’t get on anything.

These are the ways spray foam and injection foam are different, but they are similar in the ways that count the most for your home. Both materials create an air seal that helps you seal your building envelope from the top to the bottom. 

This air seal will work to create the home you’ve always wanted -- one that is energy efficient and comfortable.

Now it’s time to go more in-depth about how RetroFoam injection foam insulation is installed in existing walls without the need for a total remodel.

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How to Insulate Existing Walls with RetroFoam

Can foam insulation be installed in existing walls without the need to tear out drywall?

It sure can, and the process is relatively similar, depending on the type of exterior your home has.

Let’s take a look at how RetroFoam injection foam insulation is installed in different home exteriors and even from the inside.

See How RetroFoam is Installed with Vinyl and Aluminum Siding

Vinyl and Aluminum Siding RetroFoam Install

The process to insulate a home with vinyl or aluminum siding is the same.

The RetroFoam installer will remove a row of siding around the entire home.

Generally, a 2 ½-inch hole is drilled into each of the stud cavities, and the installer checks for any obstructions in the wall. If they find one, another hole is drilled above it. 

Next, the foam is injected into each cavity. 

The installer will run the injection hose up to the top of the cavity and begin the injection. Once they get to the middle, they run the hose from the bottom up, injecting the foam. This method helps to ensure the cavity is full.

Once the injection process is complete, the holes are plugged, and the siding is replaced.

See How RetroFoam is Installed with Vinyl and Aluminum Siding

See How RetroFoam is Installed with a Brick Exterior

Brick Exterior RetroFoam Install

The process of adding injection foam insulation to the brick exterior is different from other siding materials we work with.

In this installation process, the RetroFoam installer will drill three ⅝-inch holes into the mortar -- one at the top of the cavity, one in the middle, and one at the bottom. This method ensures the foam is injected into each cavity while completely filling it.

Once the foam has been injected, the holes are filled with mortar.

See How RetroFoam is Installed with a Brick Exterior

See How RetroFoam is Installed with Wood Siding

Wood Siding RetroFoam Install

The condition of your wood siding will determine how the installation of the RetroFoam will be done.

If the wood siding is in good condition, it can be removed, and the holes will be drilled into the sheathing underneath. Once the installation is finished, the holes are plugged, and the wood siding is replaced, much like aluminum and vinyl.

If the wood is brittle, there is a chance it could break, so it makes more sense to just drill through it. In this case, 2 ½-inch holes are drilled into the wood siding, and the foam is injected into each cavity.

Once the foam has been injected, the holes are filled with wooden plugs.

See How RetroFoam is Installed with Wood Siding

See How RetroFoam is Installed in Block Walls

Block Wall RetroFoam Install

The installation process for concrete block walls requires drilling holes into the middle of the wall to access the cores of the blocks.

The bricks’ cores are lined up, so injecting the foam is a breeze once the holes are drilled into the core. The foam will fill all of the cores and any other gaps where air can move through.

Once the cores of the bricks have been filled, the drilled holes are filled with mortar.

See How RetroFoam is Installed in Block Walls

See How RetroFoam is Installed with Stucco

Stucco Exterior RetroFoam Install

When insulating homes with stucco siding, three ⅝-inch holes are drilled into each wall cavity. One at the top, one in the middle, and one at the bottom.

Much like the process for brick exterior, this method ensures that the foam fills each and every cavity.

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

See How RetroFoam is Installed with Stucco

See How RetroFoam is Installed from the Inside

Drywall or Plaster RetroFoam Install

When installing RetroFoam from the inside, the prep is essential as you don’t want to end up with drywall dust all over your home.

Your RetroFoam installer will make sure all of the surfaces and items in the area of the home where the foam will be installed are covered in plastic.

Once all of the prep work is done and everything is covered in plastic, the installer will make a chalk line on the walls and then drill the holes centered on that line. 

Much like an exterior installation, the installer runs the injection hose from the top of the cavity down and then from the bottom up.

Once the foam has been installed, the holes are plugged, and a rough patch of drywall mud is applied.

See How RetroFoam is Installed from the Inside

Common RetroFoam FAQ's

If you have considered any of the following, check out answers below.

How Does the RetroFoam Installer Know When the Wall Cavity is Full?

Can RetroFoam Insulation Break the Drywall?

What if I Need to Run Wire in a Wall After RetroFoam is Installed?

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What Factors Determine RetroFoam Insulation Cost?

RetroFoam Dealers Set Their Own Pricing


There are RetroFoam dealers across the country, and each of those dealers set their own pricing.

While each dealer sets their own cost, several factors are universal in determining the final price tag.

  • The larger the area to be insulated, the more the injection foam will cost.
  • The number of stories the home has.
  • The difficulty of the installation.
  • The type of siding the home has.
  • If the installation is done from the inside.
  • In some cases, a dealer could implement a trip or additional charge if the project takes more than one day to complete.

The good thing about creating an air seal in your exterior walls is that it is going to make your home more energy-efficient. 

There are actually some financial benefits to making energy-efficient home improvements.

There are some tax credits available for making these kinds of improvements to your home. Talk with your tax provider to see if you are eligible.

Another avenue comes in the form of rebates. Some energy providers offer rebates to customers who make performance improvements to their homes. 

These tax credits and rebates vary in the amount you could be eligible for, so make sure you talk to your project manager about what might be available to you.

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How to Buy RetroFoam Insulation and What the Process Looks Like

Start the Process by Contacting Your Local RetroFoam Dealer


You’ve already contacted your RetroFoam dealer, and a project manager is coming out to give you a quote.

Buying RetroFoam is a reasonably straightforward process.

The project manager is going to come to your home and discuss the issues you’re experiencing. They will measure your exterior walls and figure out what kind of insulation, if any, already exists in there.

While taking measurements, the project manager will also take note of the kind of exterior your home has and any challenges there could be regarding the installation. 

Next, the project manager will come in and go over their notes with you. At this point, they will give you the concrete cost of your project. They will discuss with you the installation process and everything you can expect on the day of the installation.

The only thing left to do after this is getting your job on the calendar.

Next Steps

Hopefully, these tips have answered all your questions about RetroFoam insulation for your existing walls.

If you’d like to take a deeper dive, the Learning Center has a ton of resources like videos and articles that you might find helpful.

Get a More Comfortable and Energy Efficient Home in 3 Easy Steps

Our RetroFoam Dealer Network

RetroFoam dealers make up a large network that spans across 28 states in the U.S.

Each of these dealers goes through specific training on how to install RetroFoam insulation expertly. As part of the RetroFoam family, dealers are brought together to network and share their ideas and techniques with fellow dealers. 

We are always looking for new dealers to join the family.

Learn More About Becoming a Dealer