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Why Does Insulation Turn Black? [Moisture Warning!]

Why Does Insulation Turn Black? [Moisture Warning!]

Insulation in your home is important because it regulates your home’s temperature. Keeping your house from being too cold in the winter and too hot in the summer can save you money on your housing costs. But what if you notice your insulation has turned black — why does that happen?

Insulation turning black can be caused by excessive dust, moisture, or mold growth. If you find black insulation in your home, you can easily replace or clean it, depending on the issue and how prominent the black part is.

This article will explain the two main reasons why insulation turns black, how you can change your insulation if it turns black, and some tips for changing it yourself. Keep reading.

Black Insulation Causes

You may be worried if you find black insulation in your home, but it’s not always a major concern, and there are solutions to your insulation turning black.

When investigating your black insulation, be sure to wear proper personal protective equipment and wash your hands if you come in contact with the black insulation. 

There are two reasons that your insulation can turn black. The first is air or dirt changing its color, and the second is black mold growing on it from moisture and airflow affecting the insulation.

Airflow Can Cause Moisture, Dust, or Dirt To Build Up

First, your insulation might be black from air leaks. If there’s air flowing into your insulation, it can bring in moisture, dust, or dirt, collecting on your insulation. 

If there’s not much dirt, you can easily clean it up. Make sure the space around the insulation is also clean to ensure the insulation won’t continue to get dirty. Otherwise, you can replace the insulation, but be sure to fix the cause of the air first.

Finding black insulation resulting from airflow is beneficial because it informs you about an issue with the insulation and you need to fix it. You have two options in this situation.

First, you can fill the gap or crack where the air is flowing into to prevent airflow from affecting your insulation in the future. Filling it only works if the gap is small enough to fill and the insulation isn’t significantly damaged when you find it. 

Sometimes you can also use a piece of drywall or sheet metal to cover the gap as well. If you can’t fix the gap or the insulation is hard to clean, you can completely replace the insulation, which I’ll discuss in the next section (source). 

Black Mold Can Cause Your Insulation To Turn Black

Second, black mold might be growing on your insulation. A combination of oxygen and moisture causes black mold. Like the air and dirt in the above section, you can prevent black mold from growing on your insulation. Keep the insulation dry and ensure there are no openings for airflow. 

If you detect the black mold early, you can easily solve the problem and replace that part of the insulation. However, if you leave the black mold on your insulation for too long, it’ll disintegrate, and thus you’ll need to replace all of the insulation.

While it may or may not affect your health, insulation that has turned black is bad for the home as it reduces the effectiveness of the insulation. Change your insulation immediately if you suspect there’s black mold on it.

When removing the affected insulation, you must wear protective equipment, such as gloves and respiratory protection. You also need to dispose of it properly.

Clean the black mold area, especially if it has touched any surfaces, like walls. By doing so, the new insulation will less likely face the same black mold problem in the future (source).

If you have reservations at all about doing this safely, have a professional handle it.

How To Change Black Insulation

You should change your insulation if it has turned black and have it replaced so that it won’t cause any damage. Insulation that has turned black will likely be less effective.

The easiest way to change your insulation is by hiring a contractor to do it. They’ll choose and set up the right insulation for your home properly. By installing the right insulation, you can prevent black insulation in the future and have your insulation last longer before having to replace it again.

If you don’t want to spend money on hiring a contractor, you can replace the insulation yourself as long as you’re handy enough to get the job done. Installing insulation can take a lot of time and patience, but it can save you money on both the installation and the cost of heating and cooling your home if you do it properly.

Insulation Installation Guides

Installing insulation can seem overwhelming, especially if you have a large area to install it or are a beginner. If you’ve never done it before, take the time to read instructions and watch some videos before you begin.

To learn more about installing insulation yourself, use this step-by-step guide from Lowes, which explains all the tools, materials, and steps you need to install insulation in your home (source).

There’s also a great set of videos on YouTube from the Home Depot, which has all the information and tips you need to install insulation in your home:

The Quick Guide: Insulation & Ventilation book (available on is a great guide for learning how to keep your home energy efficient, including making sure it’s properly insulated. If you’re changing your home insulation, you’ll find this guide with pictures and easy-to-follow instructions helpful. There’s also information on ventilation that’ll keep your home even more comfortable and efficient.

Final Thoughts

Insulation turns black when it comes into contact with airflow, causing dirt or dust to collect on the insulation and make it turn black. Or, if there’s moisture and airflow, black mold can grow on and possibly eat away at your insulation. 

To solve your black insulation problem, you can clean or replace the insulation. Replacing the insulation will cost some money and time, but it’s the best way to keep your home insulated and at an energy-efficient temperature.

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