What are the signs of mold in house

Sign and symptoms of Mold in House

There are several signs that become visible if there is a mold problem in your house. The major signals are health problem and bad smell. Excessive mold growth can cause allergic symptoms to those staying around.

Allergic Symptoms from Mold

If you are suffering unusual respiratory problems or skin allergies then there might be a mold problem somewhere around. Some of the most common allergic reactions to mold include sneezing, irritation in breathing or nasal congestion. However these symptoms may not necessarily confirm the presence of mold.

For example if there is a damp problem in your bed there are chances that mold could grow somewhere underneath it and start causing health problems like skin allergies or respiratory allergies.

If the environment indoors feels heavy and musty whereas you feel better when outdoors, this could indicate a mold problem inside the house. If the allergies get worse inside the house then this would strongly indicate a mold problem indoors.

To learn more about health symptoms caused by mold check this previous post here –

What are the health symptoms caused by black Mold

Toxic Symptoms from Mold

If you are suffering symptoms like headaches, dizziness when inside the house it could indicate a mold problem.

Certain toxic species of molds like release chemicals called mycotoxins into the air which can have adverse affects on humans and animals both. The symptoms can be more severe than minor allergies. If you suffer any such problems then check for mold immediately.

Mold smell

Apart from health problems and allergies the other sure way of detecting mold is by its musty smell. When mold starts growing in significant quantities somewhere, it will give out chemicals in air that will produce a very foul smell that is difficult to tolerate.

The moment you notice such odors anywhere in your house, take action right away and go for a thorough inspection before it gets worse.

You can either check the whole area yourself or call a professional mold inspection service to do the job better.

Visible Mold

This is the most obvious evidence that you have been hit by mold. Black ugly patches spreading in some corner of the house like bathroom or kitchens are sure signs of mold. Do not make the mistake of thinking it to be dust or soot, and do not ignore it. Its time to clean.

Small mold patches like those in the bathroom, under the wash basin or between the tiles or on a vinyl door are much easier to clean yourself. Follow this previous post to learn more about cleaning mold yourself –

Mold removal guide - Removing mold with common household cleaners

Although small amounts of mold do not pose a direct risk to your health initially, but it can slowly grow larger and larger over time. Therefore in the interest of your own good health, you should take immediate action.

Other species of mold

Sometimes you might come across mold that looks unusual or does not look like mold at all. For example the kind of mold that grows on rotting food items often have a different color like white or pale blue. Such mold appears somewhat like cotton from distance.

There are even more varieties of mold that appear greenish or orange in color. Such molds can be found on ceiling edges that have water leakage problems. These kinds of mold may be difficult to spot if the underlying color of the surface acts as camouflage.

Signs of Water Problems

Long term moisture and damp problems are the primary causes of mold infestation inside houses. Even if you don’t have any visible mold signs like the ones described above, you still need to be vigilant if there has been water problem in the house in the past.

Mold growing on wall
Mold growing on wall

Sometimes mold could grow in concealed areas within the walls or wooden structures and can be difficult to spot. They will become visible or start smelling only when they have grown massively in size.

Moisture often causes damage to wall surface like peeling and cracking or swelling like bubbles. If any part of a wall is bulging abnormally it indicates moisture problems on the inside.

So if you are dealing with water problems, make sure to go for mold inspection and treatment as well.

Water Leaks

Water leaks are not very uncommon. Faucets, under sink pipes or ordinary taps, anything can leak if the structure becomes weak or gets damaged over time.

If there are such leakage problems in your kitchen or bathroom, the surrounding walls would often get affected by the water. The walls absorb water and provide a favorable place for mold to grow. Such mold is best visible on walls that are painted bright white. Black patches would become visible the very moment they appear.

However, the problem gets complicated if the leakage is somewhere inside the wall or on the other side (exterior) that is not easily reachable. Such places are hidden from view and mold growth can often go un-noticed until it becomes large and visible. Then it becomes very important to do a thorough inspection on all sides of the wall to ensure that no mold goes undetected.

Flood and water damage

If your house has seen floods and large scale water damage in the past then there are strong chances that mold has started infecting your house along with many other kinds of pests. Particular areas of the house like basements might have been badly affected by overflowing water for a very long time causing excessive damp problems.

In such a scenario you would actually need to inspect the entire house basement and even the foundation structure of the house to accurately assess the level of water damage caused. Even if the flood water has drained out, it will potentially leave behind damaged structures with cracks and crevices where moisture and damp can easily fill in. Such places will again breed mold rapidly if left untreated.

To learn more about prevention of health problems in the aftermath of a flood, check the following link –

http://www.cdc.gov/mmwr/preview/mmwrhtml/rr5508a1.htm – Mold Prevention Strategies and Possible Health Effects in the Aftermath of Hurricanes and Major Floods


High amounts of condensation could result from high humidity in the atmosphere. This happens more during rainy seasons. Condensation causes moisture to accumulate and settle on surfaces like windows, pipes and wooden structures in and around a house.

This could again lead to mold. Such kind of condensation occurs mostly on the exterior sides of the house walls. This is what causes the greenish mold to grow on the outer sides of a building which is very common.

Mold that grows on the exterior parts of a house can eventually start creeping inside. That is why it becomes important to stop it right away.

Tackling such a condensation problem can again require some investment. You need to get your walls painted with water resistant paints so that they stay protected under the effect of high humidity or heavy rain or both.


That was an overview of some of the most basic signs and symptoms of mold being present in your house. We would recommend that you do not ignore mold problems and do proper remedies on time to avoid any health problems to you or your family.

In small quantities you can clean the mold yourself. If the mold infestation is massive or affects at least about 100 square feet of area, then its best advised to call in a professional mold inspection service immediately and get it treated.

Not only should you treat the mold growth, but also the underlying cause that has helped the mold to grow. Water problems, leakage and other moisture and damp related problems should be given a permanent treatment to ensure that the mold does not reappear.

References and Resources

Check the EPA website to learn about mold and how to control it in your house –


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