It’s easy to have misconceptions about spray foam insulation when there is so much information, and misinformation, right at your fingertips.

Then you have to take into account information you might hear from friends or family that they heard second hand from someone else. It’s like playing “Telephone” when you were a kid. The message starts off as one thing and by the time it gets to the end of the chain it is something completely different.

Over the years foam insulation has changed drastically, so something that may have been true 20 years ago wouldn’t be the case today. Also, not all foam is created equal, so you can’t lump it all into one category. There are many products and manufacturers, so you can’t compare apples to apples.

 From ruining shingles to spray foam’s overwhelming smell to existing walls must be torn down to insulate your home, we’re going to address and clear up the most popular misconceptions about foam insulation.

Misconceptions about foam insulation


Closed Cell Adds Structural Integrity to the Home

While it’s true that closed cell spray foam insulation is a durable material, it’s not that durable. People say closed cell adds structural integrity, but honestly your drywall is just as strong or stronger as the foam.

Spraying Foam Insulation on the Roof Deck Ruins the Shingles

In the early days of insulating attics, people believed the insulation was a heat source. That’s not the case, as the insulation is actually a barrier between two areas of different temperatures. As for the “hot roof” theory, the unvented attic system could make the temperature of the roof go up a little, but this increase won’t cause damage to your shingles.  See Cool Roofs.

The Spray Foam Will Smell for Years

It’s important to know exactly what your contractor is spraying in your home and that they are an experienced foam insulation contractor. The materials used by Foam Connection have little to no odor, but there are products out there that have an odor.

Open Cell Spray Foam Absorbs Water Like a Sponge

There are some open cell foam products on the market that do absorb water like a sponge, but there’s also some that do not. Foam Connection only uses foam that does not absorb water.

Closed Cell is Best for the Attic Roof Deck or Floor

Many people believe closed cell spray foam is the best option for the attic because of its higher R-Value, but in reality open and closed cell foams act as an air seal. Open cell is actually the best option for your roof deck, no matter what climate zone you live in. This is because if there are any leaks in the roof, the open cell will show you, while closed cell will block the leak holding the moisture to the wood frame which can cause a lot of problems.

I Have to Leave My Home for an Extended Period after the Spray Foam has been Installed

No, you actually don’t even have to leave your home. It’s just recommended that you not be in the immediate area.

Foam Insulation Shrinks Over Time

Poorly applied or mixed foam insulation can have issues when installed, which has led to this misconception. When installed properly in adequate conditions, the foam insulation we use does not shrink.

Spray Foam Can’t be Installed in the Winter Months

Spray foam insulation can be installed in any weather conditions, all year-long. The only exception is if the weather conditions are too severe for workers to be outside.

Existing Exterior Walls Can Be Insulated Through the Top Plate in the Attic

Our process to retrofit existing walls is quick, simple, and typically takes just one day. Most walls are insulated from the outside, but we can also inject foam into the walls from the inside if needed, but never through the attic.

Electrical Work and New Wires Can’t Be Run with Foam Insulation in the Walls

Open cell foam insulation is a pliable material, which means it is easy to work with if you need to do any rewiring in the future.

Foam Insulation Will Seal all the Small Gaps Around Windows and Doors

Foam insulation will fill all of the nooks and crannies in the cavities where it is directly applied. With that being said, there is a small cavity around windows and doors that the injection foam can’t get to.

In new construction we fill this cavity with a special window and door foam to ensure these small areas are filled. With existing homes we can’t get into the cavity, but there is still a fix.

“Foam insulation will make it a little better, but not completely fix it,” Weaver said. “If you can fit a fingernail around the trim, you know you will get air leakage. Get clear silicone calk and seal around the window and door trim to help prevent this.”

A House Needs to Breathe and Foam Insulation Will Make it too Tight

When you’re concerned about your house being too tight, you’re more concerned about the air quality and humidity in your home. In a new build home, an HVAC contractor will determine the size of the system your home needs which in turn can keep your home from being too tight. The mechanicals should handle the air exchange your new home needs.

Foam Insulation Retains Water Which Leads to Mold and Other Problems

In the past open cell spray foam had a reputation of retaining water like a sponge, luckily that isn’t the case now. One of the benefits of open cell is that is doesn’t retain water and doesn’t promote mold and mildew growth.

Foam Insulation Can Completely Soundproof a Room

While foam insulation won’t eliminate the outdoor noise completely, it will greatly reduce it. One thing to keep in mind is that the location of your ductwork, pipes, appliances, and the general construction of your home will also impact sound.

Closed Cell Insulation is the Only Way to Go Because of its Superior R-Value

The Internet and many contractors might say the same thing, but closed cell isn’t always the best option.  We will provide guidance on what to use through one of our Free Estimates. 

Existing Exterior Walls Can’t Be Re-Insulated Without Tearing Down Drywall

Your exterior walls can absolutely be insulated with injection foam without tearing down your drywall. As a matter of fact, it can be done from the outside and the process only varies depending on the type of siding your home has.

Foam Insulation is Flammable

Foam Connection uses the safest products on the market. Our injection foam is Class 1 Fire Rated and so is our spray foam. Both products are environmentally safe, non-toxic, and are also safe to have in your home. These foam insulations don’t promote the spreading of fire and will actually extinguish once the flame is removed.

More Insulation is Better

More isn’t necessarily better. You could fill a space like your attic with fiberglass or cellulose, but that still isn’t going to stop air leakage because both of those materials still allow for air movement. Foam insulation creates an air seal with a minimum of 3-inches of open cell or 2-inches of closed cell.

Foam Insulation is More Expensive

Foam insulation is typically about two to three times more expensive than fiberglass or cellulose, but that’s not the whole picture.Something to consider is that traditional insulation needs to be constantly maintained and eventually replaced. Foam insulation doesn’t need to be maintained and will never need to be replaced unless it is tampered with. Foam insulation actually saves you more money in the long-run on monthly energy bills because it creates an air seal. This air seal works to keep the air you pay to condition inside, while keeping those hot or cold temperatures outside where they belong. Fiberglass and cellulose still allows for air leakage, which will end up costing you money.