Can Spray Foam Insulation Get Wet?
The answer depends on the type of spray foam and how much water it's exposed to. Here's how closed-cell and open-cell foam actually respond to moisture.
Moisture is one of the biggest threats to a building, which is why it's worth knowing whether spray foam insulation can — or will — get wet. The answer depends on the type of spray foam being used and how much water the material has been exposed to.
Closed-cell spray foam, the product commonly used in residential, commercial and industrial applications, is highly resistant to water. Because its cells are sealed and densely packed, it absorbs very little moisture compared to traditional insulation materials such as fibreglass or cellulose. Closed-cell spray foam functions as both insulation and an air barrier, helping reduce moisture movement through the building envelope. At a specific thickness, it also meets Alberta's own definition of a vapour barrier — here's the exact number code inspectors check for.
Closed-Cell and Open-Cell Foam Perform Differently
Not all spray foam products behave the same way. Closed-cell spray foam has a rigid, dense structure that resists water absorption, which is why it holds up well in basements, crawl spaces, exterior walls and commercial buildings where moisture resistance is important.
Open-cell spray foam has a softer, more flexible structure. While it provides excellent air sealing, it's more vapour-permeable and can absorb water if exposed to prolonged moisture. For that reason, it's generally used in interior applications where bulk water exposure is unlikely.
Choosing the right product depends on where the insulation will be installed and the environmental conditions it will experience.
What Happens After a Leak?
Although closed-cell spray foam is highly water-resistant, it should never be viewed as a substitute for repairing a roof or plumbing leak.
If water enters a building, the source of the leak should always be identified and corrected first. Once repairs are complete, the insulation and surrounding building materials can be inspected for damage.
One advantage of closed-cell spray foam is that it does not settle or lose its insulating value the way some traditional insulation products can after becoming wet. In many cases, if the foam remains properly bonded to the substrate and hasn't been physically damaged, it can continue performing as intended.
Built to Handle Alberta Conditions
From heavy spring snowmelt to wind-driven rain, Alberta buildings experience a wide range of weather conditions throughout the year. Selecting insulation that helps resist moisture while reducing air leakage can contribute to a more durable, energy-efficient building envelope.
At NFW Foam, we install closed-cell spray foam for industrial, commercial and residential projects throughout Central Alberta, including the Red Deer area. If you're wondering whether spray foam is the right solution for your building, our team is happy to answer your questions and recommend the best product for your application.
