Signs of a mold problem

22 signs that you may have a potential mold problem in your home or building.

Mildew/musty odors

Odors can often be the first or only sign of a potential mold problem, since mold commonly propagates in places not normally in view. This does not necessarily mean that you definitely have a mold problem, but it should prompt you to look for the other signs, or to look for the mold growth itself (How to Find Mold).

In some cases, mildewy smells will only be evident when the air conditioning or heat is turned on, or it may just be much more evident when the HVAC system is running. If this is the case, then it is very possible that you have significant mold growth within the HVAC system.

Increased allergy/respiratory symptoms

If one or more people living in a house, or working in a building (especially if it is an unusually high percentage of occupants) begin suffering allergic reactions that seem to be associated with your home or building, then it could be due to the presence of high levels of mold, especially if other signs are also present.

This may mean that people began experiencing much more allergic and respiratory-related symptoms after moving into a home, or after beginning to work in a building.

Remember, that according to a 1999 Mayo Clinic study, nearly all chronic sinus infections (afflicting about 37 million Americans) are a result of mold.

Black growth on bathroom tiles

Bathrooms are a favorite breeding ground of mold. The increased moisture and common presence of tile in bathrooms are each highly conducive to the proliferation of mold colonies.

Tile grout is porous and will allow water penetration, and behind the tiles themselves. In addition, dirt and other grime (favorite foods of mold) are easily trapped in the grout. This combination creates an ideal environment for mold to thrive.

Even if some type of sealant is applied, tiles expand and contract, and pieces of grout will eventually break off, compromising the seal. (preventing mold growth in tiles/bathroom)

Signs of toxic poisoning

Toxic black mold and other fungi produce Volatile Organic Compounds (VOCs) during the process of degrading substances to obtain nutrition. The VOCs are the cause of the typical “moldy/musty” commonly associated with fungal contamination indoors. Exposure to high levels of VOCs may irritate the mucous membranes and the central nervous system leading to symptoms of headaches, decreased attention span, difficulty in concentration, and dizziness.

Damp basements or crawl spaces

Basements and crawl spaces tend to receive less ventilation (especially crawl spaces), while also seeing cooler temperatures. With all things being equal, cooler temperatures will lead to a higher relative humidity percentage, since cooler air is able to hold less water before condensation occurs. Of course condensation means moisture.

In addition to all of this, basements and crawl spaces are more likely to be neglected than other parts of the home, so mold can grow undeterred for a longer period of time.

Also, water from leaks in the home will eventually make its way down to the lowest areas, thanks to gravity.

Condensation or rusting

Condensation on or around pipes, windows, or walls is a sign of a leak or high humidity. Rusting on pipes in particular, and anything else metal, is also a sign of a high humidity problem or nearby leak.

Discoloration of walls (water stains)

Yellowish stains on walls and ceilings are a sign of excessive moisture. In more obvious cases, where mold growth may already be in full swing, the wall or ceiling may have a greenish, brownish, or blackish discoloration to it.

You may also notice places where the paint is coming off due to moisture, or where it is “bowing” out.

One way to check for mold growth is to move a medical grade, flourescent tube (“black light”) around walls, ceilings, and even carpets while it is dark. A yellow glow is a sign of mold growth.

Loose drywall tape

This is a sure sign that moisture has infiltrated the wall.

Cracked or peeling paint

This usually means that there is moisture build up behind the paint. By the time the paint shows these signs, the moisture has often had an opportunity to spawn the growth of mold within the wall.

Warped wood

Naturally, moisture is going to cause wood to warp. If wooden materials in your home have been infiltrated by enough water to actually warp, then sufficient levels of moisture are probably present to accelerate mold growth.

Visible biological growth

Mold can take on a variety of appearances, such as black, grey-brown, grey-green, white & orange spots, or even pink or purple splotches if growing behind vinyl wallpaper. Stachybotrys is commonly a dark, slimy, greenish-black mold.

Some of the more common locations where mold is found inside includes in bathroom tile, basements/crawl spaces, and other damp and/or dark areas.