Does Fiberglass Insulation Absorb Water?

Corey's Corner Blog

Fiberglass is one of the most frequently used options for homeowners looking for an affordable way to insulate their homes. Besides its strong performance in the area of thermal resistance, sound absorbency, and fire resistance, fiberglass also proves to be an effective tool against mold and moisture damage.

However, despite being the most preferred choice for thermal insulation in the US, a major concern that most homeowners have with fiberglass is that it loses its thermal properties when it gets wet, for example from a leaky roof or burst pipe.

So, does fiberglass insulation absorb water? The answer is no, fiberglass does not absorb water, but it’s capable of holding water. Continue reading to find out more!


Does Fiberglass Insulation Absorb Water?

Fiberglass insulation does not absorb water or moisture. However, it’s important to note that it can hold water and moisture, and when this happens, the pores in the insulation will fill with water. As a result, the fiberglass will lose its ability to block heat transfer because water can transfer temperature changes more easily.

Additionally, if fiberglass retains water for a prolonged period of time, the moisture-laden insulation will become too heavy and eventually sag away from its contact point. If this happens, mold will start to grow on the surrounding wood or paper-based materials, thus making the areas damaged and look unsightly. Therefore, if you notice that your fiberglass insulation is wet, then it is probably time to remove or replace it because it will do more harm than good.

Fiberglass insulation is made from tiny strands of recycled glass fiber. It can be very bad when the fiberglass is submerged in water or is exposed to water for a prolonged period of time, as it will hold water and lose its thermal resistance.

However, if your fiberglass insulation is located in an area where the water being held can escape, then it may regain its thermal resistance back if it is not compacted when the water dries out. But if the wetness in the fiberglass insulation stays for a few days, it will compromise its insulating properties and this may lead to wood decay and mold growth.




How Can You Tell If Fiberglass Insulation Is Wet?

Below are signs that indicate that your fiberglass insulation is wet:

  • Inconsistent temperatures

When your fiberglass insulation becomes wet, its thermal resistance, as well as sound absorbency and fire resistance abilities, will be compromised, meaning it will not be as effective to control the temperature in your house. So if you have just noticed that your house has inconsistent temperature, then then your fiberglass insulation could be wet.

  • Presence of mold

Another way to tell if your fiberglass insulation is wet, is if you notice the presence of mold around the fiberglass insulation.

Fiberglass itself is an inert material which is not a viable food source for the mold, and as such, it will not promote mold growing in it.

But if your the insulation holds water for a long time, it will become compacted and lose its ability to block thermal transfer, which will result in mold forming in the surrounding materials in the area where the fiberglass is wet.

  • Noise penetration

In addition to keeping your house warm during the cold winter season, fiberglass insulation also does a great job at keeping noise and sounds away from your home. If you’re having trouble sleeping in your room or watching a movie because of too much noise from the outside, then it’s a sign that your fiberglass insulation could be wet.


What Happens When Your Fiberglass Insulation Gets Wet?

When the fiberglass insulation becomes wet, its thermal and sound insulating abilities will drop significantly.

As said earlier, fiberglass insulation is made of strands of glass fibers, and when they get wet, water droplets will displace air in the space in between the fibers. This causes a deterioration in the insulating abilities of the fiberglass.

If the fiberglass dries on time, it may regain its insulating properties. However, if it holds water for a long period, it will become compacted and lose its ability to block thermal transfer permanently. Mold may also start growing around the wet area.


Can Wet Fiberglass Insulation Be Saved?

Wet fiberlass insulation can be saved, but it all depends on how long it holds water. When fiberglass gets wet, it loses its thermal resistance until it gets dry over time.

However, if it dries out before it becomes compacted, it will regain its insulating properties. This means that wet fiberglass insulation can still be saved if it dries out on time. If the insulation dries within 2 days, it could still regain its thermal properties.

However, if it fails to dry within 2 days, or if the fiberglass is already flooded with dirty water and is completely soaked, the glass fibers can stick to the dirt and form clumps. It therefore be removed and replaced because it will have permanently lost its ability to block thermal transfer and be no longer effective as insulation.

At Peachtree Pest Control, we are committed to providing you with high-quality insulation installation, removal, and replacement services. Our team is highly skilled are trained to handle all insulation jobs, no matter the size.

We have a reputation for providing effective, practical solutions at an affordable price. When you choose Peachtree Pest Control, you not only get quality workmanship that delivers results, but the peace of mind that comes with knowing you’re dealing with the best insulation contractor in the Metro Atlanta area. So don’t hesitate to contact us today for a free estimate!