Can insulation get black mold?

Author: Charles Romaguera  |  Last update: Sunday, June 26, 2022

You are more likely to find mold on the top surface of attic insulation sheets, and you might see the spores or growth on settled dust. This growth can happen with leaky roofs and looks like a black or thin, spotty gray layer spread out in different patterns.

Can black mold grow on insulation?

Mold can grow on the fiberglass insulation backing, which is made of paper and is a mold food source. Fiberglass insulation without backing may be the best choice. Cellulose insulation is constructed of ground paper, which is an ideal food source for the growth of mold if it becomes wet.

How do you get rid of black mold in insulation?

Douse the insulation in a bleach solution (1 cup bleach and 1 gallon hot water) and scrape clean with a wire brush.

How do I know if I have mold in my insulation?

What are the signs of mold growth on fiberglass insulation?
  1. The musty smell gets stronger as you move closer to the insulated wall or attic.
  2. Experiencing constant cold, allergy symptoms, and other health problems.
  3. Observation of black, green, gray, or brown splotches on your fiberglass insulation.

Can insulation get mold on it?

Installing Insulation

Improperly installed insulation can have a negative effect on a home with regards to mold growth. For example, gaps left in the insulation can create cold spots that can lead to condensation and surface mold growth.

Insulation Issues with Black Mould

What is the black stuff on insulation?

Black Spots on Insulation caused by Air Leakage

Particulates released by combustion appliances, such as wood stoves, boilers, furnaces, diesel heaters or auto exhaust, can produce very fine soot that can build up over time in insulation. Tobacco smoke can also contribute.

What does it mean when insulation turned black?

As mentioned, loose fill insulation like fiberglass becomes discolored when it filters the air leaking from your house. While it might not be immediately noticeable, over time the air leaking from your house carries dust, other particles and moisture, which is what ultimately turns the fiberglass insulation black.

What does harmful black mold look like?

Stachybotrys chartarum typically appears black or extremely dark gray in color. This mold tends to have very round splotches with a speckled appearance. Often, you see darker layers of mold over lighter layers.

What color is blown in fiberglass insulation?

Blown fiberglass comes in three common colors: white, pink or yellow and the colors simply identify the manufacturer. Blown-in fiberglass insulation in attics typically has an R-value of 2.5 per inch. The density of the blown-in fiberglass determines the R-value just like it does for a batt.

How do you know if blown in insulation has asbestos in it?

Therefore, when looking for and trying to identify asbestos insulation, check the areas that are the most vulnerable to heat transfer. That's where you'll find insulation material, which may contain asbestos. Asbestos insulation is usually found in the less-visible parts of the home, including the following: Attics.

Should I replace moldy insulation?

When portions of insulating material harbor mold spores, then you should replace it. Even if the material dries out, mold spores can become airborne and travel to other wet areas of the house. If you catch it early enough, then you'll only need to replace a small section of material, keeping your cost lower.

Can you spray mold killer on insulation?

The short answer is no but spraying foam insulation over mold isn't a magic cure. Will spray foam kill mold? Yes, because spray foam creates an air seal and will starve that mold of its food source -- moisture and oxygen -- and will inhibit any future growth, it will also cause the mold to become dormant.

Can I remove black mold myself?

For a natural solution for getting rid of black mold, combine one part baking soda with five parts distilled white vinegar and five parts water in a spray bottle. Alternatively, you can use a chemical-based mold and mildew remover, all-purpose cleaners, bleach or dish soap.

How long does it take for mold to grow on insulation?


Mildew (mold in early stage) and molds grow on wood products, ceiling tiles, cardboard, wallpaper, carpets, drywall, fabric, plants, foods, insulation, decaying leaves and other organic materials. Mold growths, or colonies, can start to grow on a damp surface within 24 to 48 hours.

What do fiberglass fibers look like?

Under the microscope fiberglass fibers are colorless or clear, as we illustrate later in this article. It is the resin binder used by the manufacturer to stick the fibers together into a batt or a chopped piece of insulation that give fiberglass insulation its characteristic color.

Is fiberglass insulation toxic?

No long-term health effects should occur from touching fiberglass. Eyes may become red and irritated after exposure to fiberglass. Soreness in the nose and throat can result when fibers are inhaled. Asthma and bronchitis can be aggravated by exposure to fiberglass.

What color should insulation be?

Properly working insulation should be a yellow, white, green or pink color depending on the manufacturer. Move the insulation on the basement ceiling around a little bit (just use a wooden spoon or other object to push it back and forth) to see if it has darkened.

How can you tell the difference between mold and black mold?

While other types of mold may have a fuzzy, light texture, black mold will usually be slimy or wet. Some early forms of black mold have a powdery feel. Rub the mold with a paper towel to determine the texture, but be sure to wear gloves, a face mask, coveralls, and safety goggles when going near mold.

What should you do if you find black mold?

Create a bleach mixture

If the black mold growth in your home is small enough for you to treat alone, a simple mixture of bleach and water can help. Add one cup of bleach to one gallon of water and apply it to the moldy spots. You can also find commercial black mold removal products.

How do I know if it's black mold?

Black mold, as the name implies, is often dark in color. When searching for black mold, look for circular-shaped spots that are black, dark green or dark brown. Some black mold can also take on shades of orange or have flecks of white within it. Most of the time, black mold has a slightly furry appearance.

Why is my fiberglass insulation black?

Fiberglass gets discolored when it filters the air leaking from your house. Over the years, the air leaking from the house, carrying dust and other particulates and moisture, turns the fiberglass black. So wherever you see black fiberglass, dig down and look for where the air is leaking out.

Should you replace 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.

How often should insulation be replaced?

Unless damaged, it can last 80 to 100 years in most houses before it needs to be replaced. However, insulation can start falling from fiberglass batts after 15 to 20 years, so if your insulation was installed in batts well over a decade ago, it might be time for an inspection or a home energy audit.

Will insulation mold if it gets wet?

Wet insulation can be a health hazard that allows mold and mildew to grow. When you notice any wet insulation in your attic, you need to find the source of the problem and fix it as soon as possible. Wet insulation is a serious problem.

How common is black mold?

It is present almost everywhere, including the air. In general, normal amounts of mold in the environment do not pose a substantial health risk to healthy people with regular immune system function. There is no single type of mold called “black mold” — many molds are black.

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