What Are The Signs And Symptoms Of Having Mold In Your House?


Whether you’re selling a home, preparing to buy one for the first time, or just performing regular maintenance, the issue of mold may worry you – particularly if your home is in a damp environment.

In most cases, a typical home inspection won’t include mold inspections and testing. You will need to hire a professional mold inspector to check your home for issues like black mold.

So, to help you understand whether or not you may need a home inspection for mold, we’ve put together this comprehensive guide that will help you understand the signs and symptoms of mold, know what next steps to take if you think you have mold issues, and provide you with other helpful information and tips that will help you deal with a potential mold problem.

What Is Mold?

Mold is, simply, a kind of simple microorganism. It is a fungus, which grows in filaments and usually has a “fuzzy” appearance. There are thousands of types of mold – and most of them are completely harmless to humans. Mold spores are common, and present in the air we breathe.

However, when mold spores find an ideal environment – a damp, dark place where they can reproduce and feed – they can take root, and become what we know as “mold.”

Mold feeds on organic matter, such as starch, cellulose and lignin – which is why they can become present on things like drywall and wood. The mold uses these materials as a food source.

In most cases, mold is not harmful unless it’s ingested. However, there are some types of mold – “black mold” being the most well-known – which may have harmful effects on humans and animals. We will discuss that in-depth later in this guide.

To sum up, a mold is a type of fungus which tends to grow in large colonies, in areas where moisture and a food source are present. They also tend to avoid light.

Why Does Mold Form In Homes?

Mold forms in homes because, in many cases, a home is the ideal place for mold to grow – particularly in basements and other areas which may be dark and moist, and have a similar temperature all-year-round, due to furnaces and water heaters.

Essentially, there are mold spores in the air at all times – and once they find a place that’s hospitable to them, they’ll start reproducing, causing a visible mold problem.

Common Types Of House Mold

Wondering what types of mold are the most common in houses – and which ones you should be concerned about? Let’s discuss a few of the most common types of household mold now.


  • Cladosporium – Cladosporium is one of the most common household molds. It usually grows in a greenish-brown colony, but can also be nearly black in color. It is rarely harmful unless you have a mold allergy, but may cause minor issues like toenail or fingernail infections.


  • Penicillium – Penicillium is sometimes called “green mold”, as it is usually dark green in color. It tends to grow in large, consistent “patches” on the walls. As the name suggests, penicillin is derived from some kinds of this mold. However, some kinds of penicillium mold may be toxic to humans and animals.


  • Aspergillus – This type of mold is usually greenish-white in color, and may be more “raised” with a more cloudy appearance than other types of mold. It is not harmful, unless you have a weakened immune system, in which case it could infect the lungs or sinuses.


  • Alternaria – Alternaria mold is usually greenish-white, but can also appear in black patches, so it’s sometimes confused with “black mold.” Alternaria can be a factor in exacerbating asthma, particularly for those who may have mold allergies.


  • Stachybotrys chartarum/Stachybotrys atra (Black Mold) – Black mold is one of the most dangerous types of mold. Typically, this is the only type of mold you should be seriously concerned about. It produces harmful mycotoxins that can compromise indoor air quality, and cause stachybotryotoxicosis, a serious infection caused by spore inhalation.

    It is a deep black in color, and usually appears in circular “patches”, which can range widely in diameter. It is common on gypsum drywall, particularly in water-damaged homes.


Tips For Mold Prevention

Wondering how you can prevent mold from affecting your home? Here are a few tips that may help you prevent mold from forming altogether.

  • Keep things clean – Dirty surfaces can provide mold with the organic food materials they need to take hold, and start growing throughout your home. Be particularly careful in areas which may be damp, such as kitchens, bathrooms, and attics.


  • Address dampness – Dampness may be an issue if you live in an area which receives a lot of rain, or your basement floods. Make sure to ventilate your home as much as possible in humid climates, and soak up any visible moisture as soon as possible.


  • Keep the air dry – Air conditioners and dehumidifiers can help reduce the moisture content of the air. Keep your air at 40-50% relative humidity for the best comfort, and to prevent the growth of mold.


  • Heat damp areas to dry them out – You may consider using space heaters or even a hair dryer to heat damp areas of your home where mold may form. This is a short-term fix, though. It’s best to address the source of the dampness, not the dampness itself.


  • Keep the air circulating – Proper ventilation from attics, bathrooms, kitchens, laundry rooms, basements and any other place where moisture is common is essential. Make sure that your home is properly insulated and ventilated, so that air can circulate properly


How To Tell If You Have Mold In Your House

It can be hard to tell if you have mold in your house. Obviously, if you see mold somewhere, you’ve got a mold problem in your house, but mold can hide in walls, ventilation ducts, crawl spaces, and in other hard-to-see areas.

A common way to check for mold is to smell for it. A “musty” smell in an area of your home is often an indicator that there is some kind of mold present. Symptoms like a persistent runny nose, watery eyes, sneezing and throat irritation could also be indicative of mold.

In addition, anywhere that has been exposed to a significant amount of moisture – such as water damage from flooding – is a potential area where mold may be growing. Look for water where it shouldn’t be, and check areas which may have flooded in the past.

Using A Mold Exposure Test

A mold exposure test is often the best way for you to check for mold on your own. You can pick one up at any home improvement or home supply store.

Simply follow the instructions on the box. Usually, you’ll just brush the surface where you think mold may be present, and send the test strip or brush in for a laboratory analysis. If mold is present, you’ll be notified.

How To Detect Mold In Walls

If there is an area of your home where you think mold may be present in the walls – due to smell, a strange appearance of the wall, or any other factor – there are a few ways you can test this.

The simplest way is to probe the area with a screwdriver. If the area is soft or the screwdriver easily pierces the drywall, mold likely has “rotted” the surface away, and you’ll be able to see it once a hole has been opened up in the surface. Be careful when doing this – and do not do it near any wiring or electrical outlets.

You could also use a fiber optic camera to look around inside after opening a hole in the wall, but at this point, you may as well hire a professional inspector. A professional inspector has the tools required to examine the wall thoroughly, and ensure that it’s mold free – or detect any potential issues.

Can You Get Sick From Mold In Your House?

Yes. Those with allergies, compromised immune systems, asthma, or other such issues are at a higher risk – as even minor, non-toxic molds could cause a variety of uncomfortable symptoms. Mold in your house is rarely life-threatening. However, prolonged exposure is far from ideal – for a number of reasons.

Mold Poisoning Symptoms In Humans

Mold poisoning can cause a number of different symptoms, depending on the age of the affected individual, the strength of their immune system, and whether or not they have a pre-existing mold allergy. Here are a few of the most common signs and symptoms of mold poisoning in humans.

  • A stuffy or runny nose
  • Sinus issues or infections
  • Worsening or development of asthma
  • Wheezing or difficulty breathing
  • Red, itchy eyes
  • Skin itchiness, redness, or discomfort
  • Fever and shortness of breath (in severe cases only)
  • Rashes
  • Chronic fatigue
  • Persistent headaches or migraines

Most of these symptoms will only be present in homes with extremely significant levels of a harmful mold, such as black mold, or in individuals who have a compromised immune system, or other systemic health problems.

Can I Stay In My House With Black Mold?

We don’t recommend it. If you have found a small, isolated patch of black mold – and you are quite certain that there is no other mold in your house – you may be able to stay, and simply remove the mold yourself.

However, in most cases, one patch of black mold is just the “tip of the iceberg” so to speak. If black mold is present in your home, chances are that it has spread throughout many different parts of your home – and simply removing the visible mold may not be enough.

If you are young, healthy, have a strong immune system and no health difficulties, or do not have children or pets, you may consider staying in your house. Still, it’s better to be safe than sorry – so if a mold inspection reveals high levels of black mold, we do not recommend staying, until it has been treated.

How To Get Rid Of Mold In Your House

If you only have a minor, isolated mold problem, and the mold is not a dangerous type of black mold, you may be able to get rid of it yourself. By simply using a bleach/water solution, you can kill the mold on the surface of the wall or other area, and wipe it away.

If you have a small patch of mold, and you are relatively certain that there is no more mold in your home, this may be a viable option for you. However, mold removal can be quite difficult.

In addition, removing mold alone does not mean you’ll be free of the issue in the future. You’ll need to address the cause of the mold – such as water damage, excessive condensation, poor ventilation, and so on.

The best way to make sure you get rid of mold in your house is to hire a professional mold inspector. They will conduct a thorough examination of your home, and assess the molds that are present. Then, they will be able to recommend a mold remediation specialist who can help you get rid of the mold – and its root cause – in your home.

Know How To Recognize Mold In Your Home!

With this guide, you should be able to recognize common types of mold in your home, the severity of your mold infestation, and be able to take the proper next steps to get help.

If you have noticed a mold problem – or believe that there is mold hidden somewhere in your home – we recommend that you contact L&H Home Inspections right away and request an inspection. We can help you identify and isolate your mold issue, and get the mold remediation services you need to restore your home.