How long does it take for spray foam to deteriorate?

Author: Melvin Mayer  |  Last update: Thursday, June 25, 2026

Both types of spray foam insulation can last anywhere from 80 years to 100 years, with closed cell spray foam having a slight edge in terms of durability. For most families, this represents the lifetime of the house and then some!

Does spray foam degrade over time?

In general, spray foam doesn't deteriorate because of its inert nature, preventing it from reacting with other substances and reducing the risk of chemical breakdown or disintegration. The chemical composition of spray foam creates a stable, unreactive material that resists degradation over time.

How to tell if spray foam is bad?

If you're noticing that your spray foam is still soft even after a day, you probably have bad spray foam in your building. You can also determine whether the spray foam has been cured or not by using a knife. If you're able to cut through the spray foam with one quick motion, then it's still uncured.

What is the life expectancy of expanding foam?

Spray foam insulation can last anywhere from 80 years to 100 years, if it is properly applied. For most people, that could be the life of your home. They say that nothing lasts forever. “They” have obviously never hired certified Sunlight Contractors to install spray foam insulation in their home or building.

How long does it take foam to deteriorate?

Estimates vary from a few years to a million years. As always, there are various environmental conditions to consider with each scenario. It's a daunting topic to unpack, but it's absolutely crucial we do. In this article, we'll unpack why plastic foam is bad and whether it truly decomposes or not.

How Long Does Spray Foam Insulation Last?

Does foam disintegrate over time?

Because it takes hundreds of years to decompose, if it decomposes at all, polystyrene foam is effectively not biodegradable. Research suggests that plastic foam lasts in our environment for thousands of years and therefore threatens the health of wildlife for a long time.

What is the shelf life of spray foam?

In general, the spray foam systems are produced having at minimum six months shelf-life within the original unopened barrel.

Will expanding foam rot?

It's important the spray foam insulation used in roofs is breathable, as timber needs to breathe and this will ensure no problems such as rot occur. If you've heard of spray foam rotting your roof, it's likely to be the result of a spray foam contractor using polyurethane spray foam instead of Icynene®.

What causes foam to deteriorate?

Hydrolysis causes the chemical breakdown of the polyurethane polymers; this results in the physical breakdown and degradation of the product. This phenomenon can occur over several years even when the foam product is stored away from a water source.

Does expanding foam degrade?

Every data sheet or journal I can find indicates that once fully cured, it is biologically inert. Polyurethane on average shows signs of degradation in as little of 20 years, which seems to be caused primarily from fungi, but also by bacteria.

Can mold grow behind spray foam insulation?

Mold and mildew can begin growing behind the insulation which can go unnoticed until it's already become a huge problem. This often happens when the spray foam isn't installed correctly and space is left between the insulation and the wall, which allows moisture in and gives mold the perfect place to grow, unfettered.

How much does it cost to spray foam for 1500 square feet?

The cost to insulate an attic is usually between $1.50 and $3.50 per square foot. This price can change depending on the attic's size and how easy it is to get to. For a typical 1,500-square-foot attic, you pay $2,250 to $5,250.

What is the downside of using expanding foam?

While spray foam insulation can make a home more energy efficient, its downsides often out-weight its benefits. If spray foam insulation isn't installed correctly or is used in the wrong setting, it can cause all sorts of problems, from reducing ventilation to rotting wooden roof beams.

What is the downfall of spray foam insulation?

Spray foam insulation can cause bad smells

There's a pretty unfortunate problem associated with spray foam insulation – bad smells, or more specifically, a fishy odour that seems to hang around for months after installation. Whilst unpleasant, the issue is rare, especially if installed correctly by professionals.

Where should you not use spray foam?

Directly against electrical wiring or fixtures: Spray foam insulation should not be applied directly against electrical wiring, fixtures, or recessed lighting unless they are rated for contact with insulation. Contact with insulation can cause overheating and pose a fire hazard.

Does spray foam decrease home value?

Spray foam insulation provides an excellent air seal, reducing the workload on the HVAC system by minimizing air leaks. This not only extends the lifespan of the HVAC system but also improves comfort and energy efficiency, qualities that can boost a home's marketability and resale value.

How long does it take for foam to deteriorate?

Once in the landfill, it does not decompose quickly. Some estimates put the lifespan of styrofoam in a landfill around 500 years, and some put it way beyond that. Of course, some fraction of all discarded styrofoam does not go into landfills.

What is the lifespan of foam?

High Density Foam Description:

It will provide suitable support, resilience, and comfort for its given application. It is sold primarily for mattresses, average-quality sofas, chair cushions, bay windows, boats, and camping pads. Its typical lifespan is around 6 years.

How to keep foam from deteriorating?

Cushion Wrap Silk Film is a noiseless plastic silk film that you can wrap around your foam to protect it from moisture. Silk film is designed to be silent so you will not hear it crinkling when you sit on your cushion assembly.

What is the lifespan of spray foam?

Spray foam insulation lasts for 80 years to 100 years, but closed-cell spray foam will last a little longer than open-cell spray foam. For many homeowners, this lifespan will extend beyond the entire time they own their house. Closed-cell spray foam lasts longer than open-cell spray foam due to its rigid structure.

What destroys expanding foam?

Yes, WD-40 does remove expanding foam as it can break down the foam residue.

Can expanding foam go out of date?

As the catalyst dissipates, the density of the foam increases which means there is a decrease in yield. You may think you have saved money up front, but your yield will suffer. Moreover, the surfactant (surface active agents that enable surface tension for cell formation) can become less stable over time.

Does spray foam deteriorate over time?

About the spray foam insulation lifespan: The material does not deteriorate, sag, or settle. Due to its strong chemical bonding, the material produces a powerful barrier with virtually no air infiltration.

Can you spray foam over old spray foam?

If you do choose to insulate existing walls, it's once again best practice to start fresh, pulling out the old insulation and applying fresh spray foam.

How much does a 55 gallon drum of spray foam cover?

For closed-cell spray foam, you get about 30-50 square feet per gallon, depending on how thick you apply it. For open-cell spray foam, you can cover 50-100 square feet per gallon, also based on the thickness you want. A 55-gallon drum of spray foam can cover between 1,500 and 2,750 square feet.

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