What Happens When Insulation Gets Wet

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    Insulation is a crucial component in any building, as it helps regulate temperature and control the amount of heat transfer between the interior and exterior of a structure. However, one question that often arises is whether insulation can get wet. In short, the answer is yes, insulation can get wet. But, the extent to which it can get wet and its consequences depend on the type of insulation material used.

    Consequences of Wet Insulation Depending on Type

    There are three main types of insulation: fiberglass, cellulose, and spray foam. Each type of insulation has different properties and reacts differently to moisture. The consequences of wet insulation also depend on the type of insulation and the amount of moisture it has been exposed to.

    1. Fiberglass Insulation

    Fiberglass insulation is made of small glass fibers and is one of the most common types of insulation used in homes. It is relatively inexpensive and easy to install. However, fiberglass insulation is not waterproof and can absorb moisture. When fiberglass insulation gets wet, it loses its insulating properties and can become a breeding ground for mold and mildew.

    When fiberglass insulation gets wet, it loses its R-value, which measures its insulating effectiveness. Wet insulation can also become heavy and sag, which can cause it to pull away from the studs or rafters it is attached to. This can create gaps in the insulation, reducing its effectiveness even further.

    2. Cellulose Insulation

    Cellulose insulation is made from recycled paper products and is typically blown into walls and attics. It is treated with a fire retardant and insecticide to prevent pest damage. Cellulose insulation can absorb moisture, but it also can dry out quickly. However, if it stays wet for an extended period, it can lose effectiveness and become a breeding ground for mold, which can lead to health issues for the occupants of the building.

    Wet cellulose insulation can also lose its R-value and become heavy, which can cause it to settle and create gaps in the insulation. 

    3. Spray Foam Insulation

    Spray foam insulation is made of a combination of chemicals that react to create a foam-like material. It is often used in hard-to-reach areas, such as crawl spaces and attics. Spray foam insulation is waterproof and, therefore, does not absorb moisture. However, if water gets behind the insulation, it can cause damage to the structure of the building.

    Spray foam insulation can also act as a barrier to moisture, which can cause the moisture to become trapped behind the insulation. This can lead to mold growth and other moisture-related issues.

    Wet Insulation and Mold Growth

    When insulation gets wet, it becomes a breeding ground for mold and bacteria. As the moisture lingers, it can create a perfect environment for mold spores to grow and spread, leading to serious health problems. Mold thrives in damp, dark environments and can spread quickly, causing respiratory issues, allergies, and even structural damage to your home. Therefore, keeping your insulation dry and well-maintained is essential to prevent mold growth. Regular inspections and maintenance can help ensure your home is safe and mold-free.


    Insulation is essential to any building, and keeping it dry is critical to its effectiveness and longevity. While insulation can get wet, the extent to which it can get wet and its consequences depend on the type of insulation and the amount of moisture it has been exposed to. Preventing insulation from getting wet is the best way to ensure it remains effective and does not cause any moisture-related problems. This way, homeowners can keep their insulation dry and their homes comfortable and energy-efficient.

    If you’re looking for the best Insulation company in Atlanta, you’re in the right place. Georgia Insulation specializes in spray foam, batted, and blown-in insulation for Atlanta. We install and inspect insulation for new and existing homes. Request a quote today, and get started!