If you’re thinking about adding RetroFoam insulation to your existing walls, you probably want to know exactly what will be going into your home.

That is a fair question. After all, RetroFoam injection foam insulation is installed inside enclosed wall cavities, where it is designed to stay for the life of the home. You should understand what the product is made of, how it works, and whether there are any safety concerns or RetroFoam insulation problems to consider.

The short answer is that RetroFoam is a tripolymer-based resin mixed with a foaming agent and water. Once combined, these ingredients create an odor-free, non-toxic injection foam designed for existing walls.

Let’s take a closer look without getting lost in a chemistry textbook.

Key Points About RetroFoam Insulation

• RetroFoam is a tripolymer-based injection foam insulation.
• The dry resin is mixed with a foaming agent and water during installation.
• Freshly mixed RetroFoam has a consistency similar to shaving cream.
• That consistency allows it to move around pipes, wires, and other obstacles inside wall cavities.
• RetroFoam is installed in enclosed cavities, including existing exterior walls and concrete block walls.
• The finished product is odor-free and does not off-gas.
• RetroFoam has a Class 1 fire rating.
• Most potential RetroFoam problems are related to whether the home is a good fit or whether the material is installed correctly, rather than the ingredients in the finished product.

What Is RetroFoam Insulation?

RetroFoam insulation is an injection foam designed primarily for enclosed cavities, such as existing exterior walls and concrete block walls.

Unlike spray foam, which is sprayed into an open space, RetroFoam is injected through small holes drilled into each wall cavity. This allows a trained installation crew to add insulation without removing all of the drywall inside the home.

As the foam is injected, it works its way around pipes, electrical wires, old fiberglass, and other obstacles. It fills the available space and creates an air seal that helps reduce unwanted air movement through the walls.

That air sealing ability is an important part of how RetroFoam home insulation can help make a house feel more comfortable. When outside air has fewer opportunities to sneak through the walls, the furnace and air conditioner do not have to fight those drafts quite as much.

What Is RetroFoam Insulation Made Of?

RetroFoam injection foam insulation begins as a dry, tripolymer-based resin.

During installation, three components are combined in the contractor’s trailer:

• Dry resin
• A foaming agent
• Water

Once they are mixed, the ingredients create the finished RetroFoam product. At this stage, the foam looks and feels a little like shaving cream.

That soft consistency is important. Existing walls are rarely empty, perfectly shaped boxes. They may contain electrical wiring, plumbing, old insulation, fire stops, and other surprises. The foam is designed to flow through the available space and work around those obstacles as it fills the cavity.

After installation, the material cures inside the wall. The finished foam remains soft and pliable rather than becoming hard like some types of spray foam.

If you would like to look beyond the plain-English explanation, you can also review the current RetroFoam technical and safety documents.

Is RetroFoam the Same as Spray Foam Insulation?

RetroFoam and spray foam are both foam insulation products, but they are not the same material.

The easiest way to remember the difference is to look at how they are installed.

Spray foam is applied to open spaces where the framing is exposed. These areas may include attic roof decks, rim joists, crawl spaces, and the open walls of new construction.

RetroFoam is injected into enclosed spaces. It is commonly used to reinsulate existing exterior walls without tearing out the drywall.

The products also have different textures. Spray foam cures into a firmer plastic material. RetroFoam remains softer and more pliable, making it better suited for filling enclosed wall cavities.

How Toxic Is RetroFoam Insulation?

According to the manufacturer’s current product information, finished RetroFoam insulation is non-toxic, odor-free, and does not off-gas.

Off-gassing happens when a material releases volatile organic compounds, commonly called VOCs, into the surrounding air, according to the U.S. Environmental Protection Agency. This can be a concern homeowners associate with some foam products, paints, cleaners, and other household materials.

RetroFoam does not continue releasing chemical vapors after it is installed. The prepared foam is described in the manufacturer’s Safety Data Sheet as a solid, inert material.

Like any insulation, damaged or crushed dry foam can create nuisance dust. Anyone cutting into an insulated wall during future remodeling work should use ordinary dust-control practices and appropriate protective equipment.

Is RetroFoam Insulation Flammable?

RetroFoam has a Class 1 Fire Rating.

This classification is based on how quickly flames spread across the material and how much smoke it produces during standardized testing. A Class 1 rating means the material has a flame spread index of 25 or less.

RetroFoam is also designed to self-extinguish once the flame source is removed. However, a Class 1 Fire Rating does not mean an insulation product is completely fireproof. RetroFoam and other insulation materials must still be installed in accordance with applicable building and fire codes.

Can RetroFoam Help Keep Allergens and Pollutants Out?

RetroFoam does not act like an air purifier, but the air seal it creates can help reduce the pathways that outdoor air uses to enter through exterior walls.

That may help limit dust, allergens, and outdoor pollutants carried into the house through those air leaks. 

It's important to note, areas like windows, doors, ductwork, ventilation systems, attached garages, and everyday household products can also affect indoor air quality.

Are There Any RetroFoam Insulation Problems to Consider?

The ingredients in finished RetroFoam are not typically the source of RetroFoam problems.

Most concerns involve the condition of the home, whether its walls are suitable for injection foam, and the quality of the installation.

Potential concerns can include the following.

The Wall May Not Have Enough Open Space

RetroFoam needs an enclosed cavity it can fill.

Some older homes have solid masonry walls or other construction methods that do not provide enough space for injection foam.

A thorough inspection should be completed before recommending the product.

Hidden Obstructions Can Affect Coverage

Fire stops, diagonal bracing, tightly packed cellulose, or unexpected framing can divide a wall cavity.

Installers must identify these obstacles and adjust their injection pattern to help fill the available sections.

Improper Installation Can Damage Drywall

If too much pressure is used during installation, there is a risk of cracking or bowing drywall.

Trained installers monitor the amount of foam entering each cavity and watch the interior walls throughout the process.

Existing Moisture Problems Need Attention First

RetroFoam is not designed to repair a roof leak, plumbing leak, drainage issue, or other source of water intrusion.

Known moisture problems should be corrected before adding insulation.

RetroFoam Is Not Right for Every Project

The product is designed for enclosed wall cavities.

It is not the material typically used for an attic floor, exposed attic roof deck, open crawl space wall, or rim joist.

What Are the Benefits of RetroFoam Home Insulation?

When a home is a good fit and the material is installed correctly, RetroFoam insulation can offer several benefits.

RetroFoam can:

• Reduce air leakage through existing exterior walls
• Help rooms maintain more consistent temperatures
• Reduce drafts coming through the walls
• Add insulation without removing all of the interior drywall
• Fill spaces around pipes and wiring
• Help reduce some outdoor noise
• Improve the overall performance of the home’s building envelope

Results vary from one home to another. The home’s construction, existing insulation, windows, attic, foundation, ductwork, and heating and cooling equipment can all affect comfort and energy use.

Is RetroFoam Insulation Right for Your Michigan Home?

RetroFoam injection foam insulation can be a good option when your exterior walls are empty, have inadequate insulation, or contain old fiberglass that no longer does enough to control air movement.

However, the best insulation is the one that addresses the actual problem in your home. If the biggest air leaks are in the attic or basement, insulating the walls alone may not deliver the results you expect.

A professional evaluation can help determine:

• How your exterior walls are constructed
• Whether there is existing insulation
• Whether hidden obstructions may affect installation
• If there are moisture concerns that need to be addressed
• Which areas of the home are contributing most to comfort problems

Understanding the whole house helps you avoid paying for a solution that only addresses part of the problem.

Learn More About RetroFoam Insulation

Now you know what RetroFoam insulation is made of, how it works, and what safety and installation considerations to keep in mind.

If you are still weighing your options, keep digging. Learn how RetroFoam is installed, what it costs, and whether your home’s construction makes it a good fit. The more you know before requesting an estimate, the easier it will be to make a confident decision.

You can continue your research in our Learning Center.

Related Articles

What is RetroFoam Home Insulation?

Is Spray Foam Insulation Safe to Have in My Home?

RetroFoam vs. Applegate vs. Tripolymer: What is the Best Insulation for Existing Walls?

Frequently Asked Questions About RetroFoam

What is RetroFoam insulation made from?

RetroFoam is made from a dry, tripolymer-based resin mixed with a foaming agent and water.

These components create an injection foam with a shaving cream-like consistency that can fill enclosed wall cavities.

What is RetroFoam insulation used for?

RetroFoam is primarily used to insulate existing exterior walls and concrete block walls.

It can be injected into enclosed cavities without removing all of the interior drywall.

How toxic is RetroFoam insulation?

The finished RetroFoam product is described by the manufacturer as non-toxic, odor-free, and free from off-gassing.

Its Safety Data Sheet describes prepared foam as a solid, inert material.

Does RetroFoam release harmful fumes?

RetroFoam does not off-gas after installation.

Water is used during the mixing and installation process, not a chemical blowing agent.

Does RetroFoam insulation get hard?

RetroFoam cures into a soft, pliable material. It does not become as rigid as closed cell spray foam.

Can RetroFoam be installed over old insulation?

RetroFoam can often be installed in walls containing old fiberglass because the foam can compress that material as it fills the cavity.

Densely packed cellulose may need to be removed because it can prevent the foam from moving through the available space.

What are the most common RetroFoam problems?

Potential RetroFoam problems are generally connected to unsuitable wall construction, hidden obstructions, existing moisture issues, or improper installation.

An inspection can help identify these concerns before work begins.

Is RetroFoam insulation fireproof?

RetroFoam is not described as fireproof.

It has a Class 1 fire rating and is designed to self-extinguish after the flame source is removed.