Five Signs There's Mold In Your Walls

Nobody wants to find mold anywhere in their home, as it carries many health risks. However, the thought of mold lingering somewhere that you can’t easily reach is quite scary. That’s why it’s important to know the key signs of mold in your walls.

You can tell that there is mold in the space behind your walls if the wallpaper or paint is discolored and warped. This typically happens due to a pipe leak, high indoor humidity, foundation leaks, and poor ventilation in your home. Look out for dripping sounds near the suspicious wall and pay attention to musty odors, which often indicate mold.

Mold remediation is much easier if you catch the problem as early as possible. Follow along as we explore five signs that there is mold in the walls.

How To Tell If There Is Mold In The Walls

1. Earthy Odors

Many people love the smell of nature, but not necessarily in their home. That’s because the smell of earth in unexpected places at home typically point to mold. If you can’t see any visible mold, there’s a good chance the musty odor is coming from inside your walls. That’s especially true if you notice the smell eminating near a wall hiding pipes.

A leaky pipe behind the wall will create the perfect conditions for mold to grow; dark, full of stale air, and damp when a pipe leaks.  Some leaks are minor and take a while for any consequences to appear but you should contact a mold remediation service right away if you suspect mold behind your walls. The problem won’t fix itself, and it will put your health at risk unless you act quickly.

2. Bubbling/Cracking Paint

Painted walls won’t look perfect forever, but they should look great for many years. You should expect 5 to 10 great years from an interior paint job, unless something is wrong. Bubbling, cracking paint is one of many signs of mold in your walls. The bubbles in the paint are most likely trapped moisture, which is the perfect breeding ground for mold. That’s especially true if you also notice discolored patches around the bubbles.

The discolored patches will spread as long as the moisture and mold are present. Mold isn’t likely the problem if bubbles appear right after painting the walls. Bubbles in freshly painted walls are signs of poor application, which is annoying, but not as bad as mold. Contact a professional if you discover discolored, cracked, and bubbling paint patches on your walls. 

3. Discolored Wallpaper

Just as mold can grow beneath paint, it can grow behind wallpaper. Newly applied wallpaper should sit flat against the wall and look exactly as it did when you bought it. However, leaks, trapped moisture, poor application, and contamination can cause mold to grow. Since wallpaper isn’t breathable, the moisture cannot escape, which creates the right conditions for mold.

Many people find out they have mold under their wallpaper when they discover warped, discolored patches. Brown, yellow, and black areas are key signs of mold in your walls, and they won’t go away without intervention. Plus, over time, moisture can weaken the wallpaper and let mold spores escape. That’s why it’s important to contact a professional and address the problem as soon as possible.

4. Warped Drywall

Sometimes, people replace wallpaper or repaint walls and think the mold problem is done. Unfortunately, those are only temporary fixes if the mold is coming from the drywall. Drywall is a common mold hotspot due to its porous nature, which is problematic when moisture is present. This becomes much worse when the drywall features cellulose paper, which is common.

Mold thrives on cellulose as much as it does on moisture and darkness. Eventually, the drywall will become warped and discolored due to prolonged moisture and mold. Naturally, this will affect the wall covering if you don’t address the problem quickly.

5. Scary Test Kit Results

Today, you can easily find at-home mold test kits that anyone can use. They are useful if you smell something musty and suspect mold, but can’t figure out where it’s coming from. You’re best off using a surface swab test kit if you discover unusual patches on your walls. Swab kits let you test suspicious areas directly, so you’ll know if mold is growing in and on your walls.

Other mold test kits test the air to determine if mold spores are present in your home. They are quite effective, but they don’t necessarily tell you where the mold is. However, the results of an air test will at least let you know that it’s time to hire a mold remediation specialist. Document the results, so you can pass on that information when you hire a professional.

What Causes Mold Inside Walls?

High Indoor Humidity

The ideal indoor humidity is between 30% and 50%, because it supports comfort and helps prevent mold and mildew. However, mold and mildew are significantly more likely to grow in homes with 50% to 60% indoor humidity. Not only that, but excessive humidity also attracts crickets, spiders, silverfish, dust mites, and other pests. Every homeowner should have at least one hygrometer. This device monitors humidity, and you can use the results to humidify or dehumidify the air, as needed. Homeowners in humid climates, like Florida and Louisiana, can benefit from using a ehumidifier.

Poor Ventilation

Even without pipe leaks, mold can still grow in and around your walls if your home is poorly ventilated. Without proper circulation, damp air lingers and eventually settles on surfaces in your home. This includes the walls, ceiling, furniture, and more. A good example of poor ventilation causing mold is when it appears after showering without putting on a fan.

Ideally, you should run the bathroom fan for at least 20 minutes after showering to dissipate as much moisture as possible. A kitchen, attic, laundry room, and bathroom must also be well ventilated, or else there’s a huge risk of mold. If those spaces aren’t ventilated, it will cost a lot to correct the issue. However, it’s worth it considering how much you’ll improve the indoor air quality and prevent mold growth when you have good air flow in your home.

Leaking Pipe

A leaking pipe is among the biggest cause of mold in the walls. You can’t see what’s going on behind them, so the situation can sometimes be difficult to identify. Warped, bubbling, and peeling paint or wallpaper are indications that there may be a leaking pip behind a wall. However, also listen for dripping sounds and pay attention for musty odors. Unexpectedly high water bills can also indicate there's a pipe leak. The problem will continue until it's fixed, so don’t hesitate to call a plumber.

Foundation Leak

A leak in your home's foundation is extremely dangerous, as it can threaten your home’s structural integrity. However, you will likely notice mold in your walls before your home suffers any structural damage. Moisture in the foundation can travel upward into your walls and floors.

Foundation leaks often happen due to poor landscaping and gutter problems. A messy, clogged gutter or downspout can pour water into the ground near your home’s exterior walls. From there, the water can travel down into the foundation. This can eventually cause cracks, which will significantly make the problem worse. That’s why it’s important to call a foundation repair contractor right away if you suspect fa oundation leak.

Summing It Up

Cracked paint, bubbling wallpaper, and discoloration are signs of mold in your walls. You can also tell mold is present in and around your walls if you notice a musty odor. It’s important to use a mold test kit or hire a mold inspector and remediation service if you suspect mold behind your walls.

Related Guides:

• How To Tell If Mold Has Spread
• Eleven Signs Of Mold In The House