How to Detect Mold in Walls: A Guide for Homeowners

How To Detect Mold in Walls

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Having mold in the home can vary in its effect on your home. It can start as a minor inconvenience before becoming a major problem affecting your home, health, and finances. Mold can sometimes go undetected, but the most likely place you are to find mold would be on (and sometimes within) your walls. Here is how to detect mold in the walls.

Signs of Mold In Walls

Musty Odor

Before you ever see mold, you are more likely to smell it. This is because mold carries a heavy, musty odor. The best thing to compare the odor to is that of an old attic or basement. If you smell this odor, especially if it is strong, you need to be careful, as mold spores are in the air. If you inhale mold spores, there is a chance that you can develop a respiratory illness. For future interactions with mold-afflicted areas, wearing a face mask, preferably a respirator with proper filtration specific to this job, is strongly recommended. An N95 mask falls far short, letting mold spores into your respiratory system.

Wall Discolorations

One of the most obvious signs of mold is discoloration on your walls. This is because mold can stain whatever surfaces it can latch onto. You should look for dark, blue, or green splotches of discoloration on your walls.

The Wall Feels Cooler Than Other Walls

This may seem odd, but check how your home's walls feel. If one of them feels significantly cooler than the others, that could be a sign of mold growth on the other side. Mold thrives on an organic food source, moisture, and wet drywall. This makes the drywall feel cooler if the other site is wet and it's an internal wall with no insulation; it's likely close to the home's ambient temperature.

Peeling Paint or Wallpaper Bubbling

Mold can damage the paint on your wall. If your paint is peeling, this is typically a sign of moisture forming underneath the paint, which invites mold growth. It will have the same effect on the wallpaper.

Wallpaper is like a huge Southern BBQ on a hot summer's day. Not only can it attack the wallpaper depending on its makeup, whether organic in part or whole, but mold also seems to love the adhesive used for applying wallpaper.

Water Stains on Baseboards

Where there is abnormal water presence, there is likely to be mold growth. This is because mold is attracted to moisture. If you see water discoloration on your baseboards, you are likely looking at mold in your walls.

What Causes Mold in the Walls?

Wet Building Materials

Sometimes, for many reasons, the building materials in your home get wet. Maybe there is a leak that introduces water into your home. Maybe there is a burst pipe. The point is wet building materials practically invite mold into your home. Mold will practically flock to the moisture in the building materials, particularly wooden support structures and the drywall that covers them.

Improperly Installed Windows and Doors

Windows and doors can often be the first defense against mold growth. This is because the biggest enemy of mold is proper ventilation. Mold cannot thrive in a dry, properly ventilated environment. When windows and doors are improperly installed, you have poor ventilation, especially if the windows allow moisture to enter the house. When that moisture accumulates, it can cause mold. The accumulated moisture can also spread to the walls, and where the moisture goes, mold will follow.

Roof Leaks

When you have damaged or completely missing tiles on your roof, that drastically increases the likelihood that you will have a leaky roof. When your roof leaks, water accumulates in your attic and soaks into the wooden structure of your home. Eventually, the moisture will spread to your walls. When that happens, mold growth is inevitable, particularly during the summer when high humidity occurs.

Plumbing Leaks

The most frequent way mold grows on your home's walls is if there are plumbing leaks. If you have any plumbing in your home's walls, then a leak would certainly supply the moisture necessary for the walls to grow mold, and it doesn't take much. A slow drip can quickly turn into a mold colony. Remember, there is no “air conditioning” inside the wall. The attic and exterior walls are also full of insulation. Certain types of insulation have less risk, others more. It depends on if they absorb moisture at a high rate.

Appliance Overflow

When you use an appliance that frequently uses large amounts of water at a time, an overflow can lead to mold on the walls. For example, if you have a bathtub and it overflows, especially if it is located upstairs, that water can go into vents or seep into baseboards. If left unchecked, then mold growth can easily and quickly occur.

Is Mold Dangerous To My Home?

Mold can be extremely dangerous if it is left to its own devices. Mold is a destructive organism, and when it is given enough time to get into the wood-framed foundation or the drywall in your home, it can severely weaken those materials, making your home unsafe.

The spores that mold emits into the air are also dangerous to your health. It is easy to inhale mold spores without even realizing it. When that happens, the spores can enter your respiratory system, causing any number of potential illnesses.

Let's look into some details of how bad mold can be. Aspergillus is a mold genus, but it's not the worst one, or the one referred to often as the dreaded Black Mold, which is Stachybotrys chartarum, but we will only look into Aspergillus. If you would rather bypass safety recommendations, this article will show you the misery of Aspergillosis Disease. We haven't yet explored the infamous Black mold (Stachybotrys chartarum), or how it was used as a biological weapon throughout history, even by the US Government.

How to Detect Mold In Your Walls

Moisture Meter

If you want to find mold hiding in your home's walls, then you need to find the moisture that the mold is living off of. This is where a moisture meter comes in handy. It can help you find the highest concentrations of moisture in your home. Where there is moisture, there is mold.

Thermal Imaging Camera

You may find it interesting that mold gives off a heat signature. A thermal imaging camera will allow you to see that heat signature where the naked eye can't. If you look at a wall that should not have heat coming off of it and find heat anyway, then there is a good chance that you are looking at mold.

ERMI Mold Test

One of the best, most reliable ways of determining whether or not there is mold in your walls is to send away for an ERMI mold test. These results are quite accurate and will give you a conclusive answer.

Know When You Need Help

Taking the DIY approach is only viable at a certain level. If you find that locating mold in the walls of your home is difficult, but you are sure that the mold is present, it is time to call in outside help. Enlist the help of a water/mold damage expert with the proper tools and know-how to detect mold in your home. They will inspect, assess, test, and eliminate the mold in your home if it is a serious threat.

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