You’ve probably heard all the buzz around foam insulation.
Install it once and never think about it again.
And while a lot of that is true, problems tend to pop up when homeowner expectations don’t quite line up with the reality of what foam insulation can (and can’t) do for a specific home.
That expectation gap is where disappointment happens – and it’s completely avoidable.
Let’s break down the most common assumptions homeowners have about spray foam and injection foam insulation, what’s true, what’s not, and how to make sure you’re getting the biggest bang for your buck.
• Foam insulation helps with sound dampening, not full soundproofing.
• Sprayfoam costs more up front than fiberglass and cellulose, but it lasts long and performs better.
• DIY spray foam projects often waste product and fail to create a proper air seal.
• You can run wiring and access plumbing through most types of foam insulation.
• Foam insulation can pass building code through performance, not just R-Value.
• Many foam products are Class One Fire-Rated, and RetroFoam carries this rating and is self-extinguishing.
• Closed cell spray foam doesn't fix active water leaks -- it can actually hide them.
One of the most common questions homeowners ask is: “Is spray foam insulation good for soundproofing?”
There’s a big difference between soundproofing and sound dampening.
Foam insulation – especially injection foam and open cell spray foam – does have sound-dampening qualities. It helps reduce vibration and airborne noise compared to fiberglass, which does little more than sit in the cavity.
However, foam insulation alone will not completely eliminate noise. Sound transmission depends on:
Foam’s sound control is a nice bonus, but it shouldn’t be the primary reason you insulate.
Homeowners often compare insulation material costs and expect them to be similar. For example:
Spray foam insulation and injection foam, like RetroFoam, cost more upfront because they do something fiberglass and cellulose can’t – they both create a continuous air seal.
That air seal is what:
Fiberglass and cellulose also settle and degrade over time, often requiring replacement. Foam insulation is typically a one-and-done installation.
So while spray foam insulation cost vs. fiberglass is higher upfront, the long-term value often favors foam.
DIY kits make spray foam look deceptively simple.
Is spray foam insulation a DIY project?
Technically, yes, it can be.
Is it a good idea for most homeowners? Usually, not so much.
Common DIY issues include:
Spray foam only works when applied at the correct thickness to form an air seal. Miss that target, and you’ve essentially paid premium prices for mediocre insulation.
Small, controlled projects may be fine, but whole-home or large-area foam insulation is best left to professionals.
This misconception usually comes from people thinking all foam behaves the same.
In most existing homes, walls are insulated with:
These materials are more pliable, easy to cut, and simple to work with for repairs. Running wire through foam insulation or accessing plumbing is absolutely possible. Electricians and plumbers do it all the time.
The confusion comes from closed cell spray foam, which is dense, rigid, and much harder to cut through. That’s why understanding which foam product is being installed matters.
R-Value gets a lot of attention, but it’s only part of the story.
Building codes allow spray foam insulation to pass based on performance, not just prescriptive R-Value.
Why? Because R-Value measures thermal resistance, but not air leakage.
Foam insulation:
That air seal is why foam insulation can meet building code requirements even at lower R-Values than traditional materials.
“Is foam insulation flammable?” is a fair question, and a common concern.
High-quality foam insulation products, including many injection foams and spray foams, are Class One Fire-Rated.
That means:
Always confirm fire ratings with your insulation contractor – but foam insulation isn’t the fire hazard many people assume it is.
This one can cause serious problems if misunderstood.
Closed cell spray foam is water-impermeable, which means water can’t move through it.
But that doesn’t mean the leak is gone. Instead, the water takes another path, leading to structural damage, foundation issues, and wood rot.
Any active water leaks must be fixed before installing closed cell spray foam. Foam insulation is not a waterproofing solution – it’s an insulation and air sealing solution.
Foam insulation is one of the most effective ways to improve:
But the key is understanding what it does, and what it doesn’t do.
Open conversations with your contractor, asking the right questions, and knowing the reality behind common myths ensure you’ll be happy with the results long after installation day.
Adding foam insulation to your home can be a game-changer, but only when your expectations align with reality. If you want to learn more about what foam insulation can and can’t do in your home, check out our Learning Center. If you’re ready for the next steps in adding foam insulation to your home, head on over to our Find a Dealer page to find a RetroFoam insulation contractor in your area.
Does RetroFoam Insulation Work for Sound Dampening?
Repairing Plumbing and Fishing Electrical Wire Through Insulated Walls with RetroFoam
What is the Highest R-Value Insulation?
Foam insulation helps reduce noise by dampening sound, but it does not fully soundproof a home on its own.
Yes, spray foam insulation costs more upfront than fiberglass, but it lasts longer and provides air-sealing benefits that fiberglass cannot.
No.
Spray foam insulation does not fix active water leaks and may hide them if installed before repairs are made.
Many spray foam and injection foam products are Class One Fire-Rated and meet building code requirements when properly installed.
Yes.
Injection foam and open cell spray foam can be cut and worked around for wiring and plumbing access.