Is Spray Foam Insulation Waterproof? A Brief Guide to Choosing Water-Resistant Material

The primary purpose of insulation, including cell spray foam insulation and its closed-cell counterpart, is to regulate the temperature of a building. High-quality insulation materials regulate temperature and contribute to the property’s overall well-being by keeping it dry.

This is particularly important in maintaining structural integrity and preventing moisture and water damage. This is the reason why water-resistant insulation is on the trend nowadays.

If you’re particularly interested in spray foam insulation type, you may have wondered, “is spray foam insulation waterproof?” Discover the answer to this question below.

Waterproofing Spray Foam

Insulation that lacks waterproof qualities, such as some open-cell foam products, can lead to high moisture conditions within a property. This affects the building’s energy efficiency and compromises indoor air quality.

Water accumulation can result in sudden temperature shifts, increased energy consumption, and less energy-saving efficiency.

Water accumulation can result in sudden temperature shifts and less energy-saving efficiency. High moisture levels can lead to various humidity issues, accumulated condensation, or sometimes mold.

Water itself can lead to the deterioration of insulation material. When it seeps into the insulating substance, it occupies the space designated for air, essential for effective insulation.

Read also: Is Blown-In Mineral Wool Insulation Effective?

This displacement can significantly reduce the material’s insulating properties, leading to increased heat transfer and reduced energy savings.

Water is a better heat conductor than air, so it will let warm air get into or out of the properties more efficiently. Over time, the insulation material will be destroyed by water. So, in conclusion, it’s essential to make sure that you use waterproof insulation to accomplish a dry and healthy building and better energy savings.

To answer whether spray foam insulation is waterproof, it’s important to consider the open-cell vs closed-cell types. Closed-cell spray foam offers better water resistance and is less likely to absorb accumulated water than open-cell foam, making it a more suitable choice for moisture-prone areas.

This makes it more suitable for moisture-prone areas like basements or exterior walls. As you may have known, there are two types of spray foam insulation: open and closed-celled.

Read also: 5 Disadvantages of Spray Foam Insulation

The closed-cell spray foam does have waterproof quality, making it a more effective choice for spray foam roofing or as a significant layer of insulation against external temperature changes, while the open-celled type doesn’t.

Why? This is because close-celled spray foam possesses higher density characteristics, while the other tends to be more lightweight to allow more expansion.

Open-celled spray foam, while beneficial for insulating nooks and crannies, doesn’t provide as much protection against accumulated water as the closed-celled type.

When finding the right spray foam for your needs, it’s crucial to consider that closed-cell spray foam has stronger resistance to various elements, including water.

Best Waterproof Spray Foam

Here are three highly recommended spray foam installation products that feature waterproof quality, making them suitable for various applications, including SPF roofing systems.

These products not only provide effective insulation but also contribute to the overall energy efficiency of a building by preventing water ingress and maintaining optimal thermal conditions. :

  1. Great Stuff Smart Dispenser

This product allows more precise application and control as it features a drip-free straw dispenser. You can use the dispenser’s trigger to control the foam flow. It’s applicable on metal, wood, and masonry surfaces.

It is capable of filling up to 1-inch width gaps. You only need to wait 15 minutes for the foam to dry up and 1 hour to trim it. You’ll need to wait 24 hours for the foam to be fully cured.

  1. DAP Touch ‘n Foam MaxFill

The next recommended waterproof spray foam product is resistant to rain, snow, and extreme temperature changes. However, it’s prone to discoloration due to not being UV-resistant.

This product has a straw applicator for more accessible and precise application. The drying and curing period is quite similar to the previous product.

  1. Red Devil Foam & Fill

Last, this list’s recommended spray foam insulation product can create an airtight and waterproof barrier to help seal out moisture and humidity.

Read also: The Problems With Spray Foam Insulation in Attics

This spray foam applies to unpainted and painted surfaces of wood, fiberglass, concrete, aluminum, masonry, cinder blocks, and concrete material. The drying and curing times are the same as the other products mentioned.


In conclusion, the effectiveness of spray foam insulation in waterproofing largely depends on whether you choose open-cell or closed-cell foam. Closed-cell foam’s superior resistance to accumulated water makes it a more reliable choice for moisture-prone areas.

By carefully selecting the right type of spray foam, you can ensure effective insulation and moisture control in your building.

Now that your question of whether spray foam insulation is waterproof has been answered, you can choose the best products available. You may use the recommended list above to help you find one.

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Insulator is a skilled author and Insulation expert with years of experience in the field. He has authored several articles and books on various aspects of insulation installation, maintenance, and repair.