Can insulation foam get wet?

Author: Prof. Jake Conn DDS  |  Last update: Wednesday, November 19, 2025

Closed-cell spray foam insulation is highly moisture-resistant, meaning it can handle some level of wetness without immediate damage. However, it is not completely waterproof and prolonged exposure to water may eventually degrade its properties.

Is insulation foam waterproof?

Some spray foam is waterproof, but not all. Specifically, open-cell foam is not waterproof, but it is water-resistant. Closed-cell foam is also water-resistant, but only the higher-density closed-cell foams are truly waterproof.

Is insulation ruined if it gets wet?

While insulation is not automatically ruined if it gets wet, leaving it damp for too long can significantly degrade its performance, reduce its R-value, and promote mold growth.

What happens when insulation foam gets wet?

Once insulation gets wet, it loses its ability to trap air effectively, reducing its thermal resistance (R-value). Moisture can also lead to mold growth, which poses health risks and can damage the surrounding structure.

Does foam get ruined by water?

Can foam insulation get wet? Yes, it can get wet without absorbing water. However, water pressure can damage the foam, potentially compromising its insulating properties.

What To Do When Insulation Gets Wet?

What happens to foam in water?

The foam will naturally break down and dissolve back into the water. Foam can contain high levels of contaminants that may pose a health risk to humans and pets. If you touch foam, wash your skin with soap and clean water as soon as possible.

Can water leak through foam?

Closed-cell foam is a top choice for keeping moisture out of your home. It's different from open-cell foam because it doesn't let air or water through. This makes it great for stopping leaks and preventing water damage. Closed-cell foam is special because of its density and structure.

How long does insulation foam take to dry?

Typically, it can take between 5 and 60 minutes for the foam to become tack-free. Full cure may be reached in a time range of about 8 to 24 hours, depending on the product and site conditions. Consult the product label and instructions regarding cure times.

Is great stuff foam waterproof?

Flexible and easy to apply, GREAT STUFF™ Window & Door Insulating Foam Sealant quickly and cleanly forms airtight, water-resistant seals between framework and rough openings that withstand the elements.

Is there a downside to spray foam insulation?

Spray foam insulation is a good insulator in terms of keeping a room warm or cool. But its many downsides outweigh the benefits. These include, making it more difficult getting a mortgage, potential health issues, environmental damage, ventilation issues and a lower home valuation.

Can insulation be left out in the rain?

As commonly known, even the best insulation can be destroyed by water. The same applies to PIR boards. Leaving PIR foam insulation exposed to water for prolonged periods can cause permanent damage. In general, leaving PIR boards under the influence of water for more than 30 days can affect their thermal properties.

How to tell if insulation is damaged?

Signs Of An Insulation Issue
  1. Expensive Energy Bills. If your energy bills have been rising steadily without a change in your consumption, it is typically a sign that your home temperature maintenance system is troubled. ...
  2. Inconsistent Temperatures. ...
  3. Indoor Condensation. ...
  4. Mold Spots. ...
  5. Unwanted Visitors. ...
  6. Ice Dams.

How long does insulation take to dry if it gets wet?

How Long Does It Take Wet Insulation To Dry? The type of insulation, ventilation, temperature, and the humidity all play a role in determining the drying time. Typically, if the insulation does not dry within 2 or 3 days, it is advisable to remove it to prevent mold growth and wood decay.

Is 2 inches of closed cell foam enough?

The Bottom Line About How Much Insulation You Really Need

Many online experts claim that two inches of closed cell spray foam is enough for any project. These experts present data and charts to demonstrate the efficiency of insulation reaching a reasonable high at two inches.

Is insulation allowed to get wet?

Wet insulation can be a dangerous hazard in your home or building. It can lead to the growth of mold and mildew, which can cause respiratory issues for occupants of the building as well as damage to the structure itself.

Can water get through expanding foam?

To answer shortly: YES, spray foam can resist water from entering your home. The air-tight sealing it provides helps keep moisture from seeping inside and damaging your property. Many use it successfully for sealing home spaces prone to leaking, including crawlspaces and basements.

What happens to foam if it gets wet?

Open-cell spray foam is more porous than closed-cell foam, so it may absorb water if it gets wet. This can lead to decreased R-value and, over time, the potential development of mold or mildew if the moisture is not properly addressed.

Where not to use great stuff foam?

Do not use GREAT STUFF™ Insulating Foam Sealants for filling closed cavities or voids such as behind walls and under tub surrounds. This improper use of the product could result in the accumulation of flammable vapors and/or uncured material.

What is the life expectancy of great stuff 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.

Can spray foam insulation get wet?

Spray foam insulation can get wet, but the type of spray foam installed will determine the extent to which it can deal with moisture. For example, closed-cell spray foam insulation has a higher water resistance than open-cell spray foam.

Does foam insulation go bad?

Spray foam: 80-100 years with correct installation

Even if your insulation is still “technically good” according to manufacturer's recommendations, you still need a professional to take a look if you have concerns. The energy-efficiency experts agree: Insulation can lose its effectiveness over time.

Is gorilla expanding foam waterproof?

Product information

This 750ml expanding foam filler by Gorilla Filler is perfect for weatherproofing and sealing gaps. It expands to fill voids, providing an airtight and waterproof seal.

When should you not use spray foam insulation?

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.

Will expanding foam stop mice?

In fact, expanding foam products have been developed that bond to most common building materials while also including an olfactory deterrent to help prevent pest incursion. One such foam is specially formulated to block mice, birds, bats, tree squirrels, and other pests such as ants, roaches, and spiders.

Can foam be waterproof?

Waterproof foams are often used in marine applications, industrial applications that involve heavy exposure to water, moisture, and chemicals, and many other harsh applications. These types of foams can also be made to resist mold and mildew growth, degradation, and heat and flames.

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