When Not to Use Spray Foam Insulation?

Spray foam insulation is currently one of the best home insulation available in the market. With one of the highest R-values and offering a tight air seal for maximum efficiency provided by an insulator, spray foam insulation has been adopted extensively.

The versatile expanding foam can creep into hard-to-reach places like corners, cracks, crevices, etc., and provide insulation. This is a unique characteristic of expanding foam insulation as it makes installation easy and highly efficient.

However, in some places, spray foam insulation can’t be applied, and in some places, spray foam insulation mustn’t be applied for the sake of the safety and well-being of the user.

In this article, we will be exploring the cases where you shouldn’t use spray foam insulation as a method of wall insulation and attic insulation.

Where Not to Use Spray Foam Insulation?

Where Not to Use Spray Foam Insulation

When buying any product, we must always be aware of its limitations and how to use them to get maximum cost worthiness. Expanding spray foam is a versatile solution used in homes for wall insulation and attic insulation.

However, there are cases when you shouldn’t use spray foam insulation or consider it a viable alternative.

Let’s discuss some of them.

Spray Foam Shouldn’t Be Used in Areas That Are Too Close to Electrical Circuits.

When you have exposed electrical circuits, such as electrical boxes, it is better not to use spray foam insulation. If the insulation gets inside the electrical system, you can jam up the parts, exposing chemicals that are flammable to an electric source, which is a bad idea.

In case you are determined to use spray foam insulation, you can go for low expanding foam that has more resistance in such situations.

Spray Foam Shouldn’t Be Used Too Close to Ceiling Lights and Ceiling Light Boxes.

It would help if you didn’t use spray foams for ceiling insulation to insulate areas near the ceiling canister lights that are recessed. The problem is that lighting devices also emit heat, and the expanding foam insulation can trap the heat from dissipating.

Increasing heat can cause the bulb to malfunction and increase the risk of a fire. It is advised to consult an expert or licensed professional if you think the insulation is closer to the ceiling lights, especially canister lights.

Open Cell Spray Foam Shouldn’t Be Used On the Roof.

Spray foam is chemical and chemical mixtures are bound to rot your roof due to prolonged exposure to heat and light.

Moreover, moisture content, a huge factor determining insulation efficiency, can escape easily through open-cell spray foam and accumulate under the roof sheathing. This moisture build-up over time can cause corrosion in the roofing.

It is advised to use only closed-cell spray foam while insulating the roof regardless of the climate and the timezone you’re living in.

Spray Foam Has Better Alternatives When It Comes to Closed Cavity Spaces

Yes, spray foam is better at hard corners and hard-to-reach places. However, injection foams are a better alternative for closed-cavity spaces, and this is because the expansion rate of both spray foam and injection foam differs from each other.

While installing, injection foam has a slow expansion rate, which is desirable in closed-cavity places to reduce pressure. 

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Spray Foam Shouldn’t Be Used at All If You Have a History of Skin Problems, Asthma or Other Respiratory Problems.

Spray foam, whether closed-cell spray foam or open-cell spray foam, is made of chemicals and contains highly reactive components, including isocyanates. Prolonged exposure to such reagents can create skin problems and breathing problems.

Further, if you have pre-existing skin, asthma, or other respiratory problems, the person carries a higher risk when exposed to harmful chemicals.

Spray Foam Shouldn’t Be Used Around Windows and Doors.

High expansion spray foam can pose quite a problem if installed incorrectly. It can push the jamb inwards, making it nearly impossible for them to open. This can be avoided by using better alternatives and minimizing expanding foam insulation.

You can also opt for multiple layers of foam. The first layer of foam should be applied and left to expand and cure. If necessary, add additional layers.

Spray Foam Shouldn’t Be Used Near a Spark or Open Flame.

Technically, expanding foams are designed to prevent the spread of flames and heat. However, there’s always a risk when there’s an actual product involved. Especially during installation, the cans expel highly volatile polyurethane components.

This can be dangerous while installing spray foam inside a crawl space or a cabinet since the risk of gas accumulating and a spark igniting it is high.

Always turn off lights and make sure not to smoke while installing expanding foam. Try to open windows to increase ventilation, and wait till the spray foam cures.

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Final Thoughts

Spray Foam is a versatile solution with high insulating and air sealing properties. Spray foam insulation is perfect for hard angles, cracks, and crevices. It can fit inside cavities and create air seals due to its expanding properties.

However, the product isn’t perfect, and there are cases when it shouldn’t be used to have maximum efficiency and aesthetics. This article has discussed some common instances where spray foam isn’t the best insulation solution. Most of the problems with spray foam insulation revolve around the explosive properties of its components.