• August 15, 2024

What Causes Mold On Walls and How To Prevent It?

Mold growth is a common problem in many homes, and can lead to health issues and structural damage. It is important to know what causes mold on walls to effectively treat and prevent infestation.

In this article, we will talk about common types of mold, symptoms of its exposure, and how it affects health. We will then discuss 11 factors that cause mold on walls, so you can address them to maintain a healthier and safer living environment.

What is Mold?

Before we discuss what causes mold on walls, let's first see what it is.

Mold is a microscopic, multicellular fungi that exists as mold spores in the air. On the surface of your walls, furniture, and ceiling, these spores form colonies that look like black, grey, green, or powdery patches.

While many believe that molds are caused by moisture, they actually exist in both dry and wet conditions. However, for the spores to sprout and form colonies, relative humidity of at least 55% at 65 degrees is required, which is why moisture is considered favorable to mold growth.

Common Types of Molds

Multiple types and subspecies of molds exist and grow colonies in your home. Here are some of the most common airborne molds and their effect on your health:

• Aspergillus: It is one the most common household molds in America and appears as a green or white powder with dark spots. It causes allergic reactions in respiratory systems, as well as other vital organs.
• Cladosporium: Cladosporium mold is brown, green, or black, and causes allergy-like symptoms. Prolonged exposure can also cause aggravation of asthma.
• Penicillium: Side effects of this fuzzy mold range from mild allergic reactions to severe nephrotoxic, cardiotoxic, psychotoxic, immunosuppressive, and even carcinogenic symptoms.
• Fusarium: It results in localized infections of nails (onychomycosis) and eye (keratomycosis).
• Stachybotrys: Also known as black mold, Stachybotrys causes nasal irritation, burning in the eyes, cough, chest congestion, and shortness of breath.

Symptoms of Mold Exposure

Mold growth in the house might not always be immediately visible. However, the exposure causes some symptoms, which if present, necessitate an inspection.

Here are common symptoms of mold exposure:

• Sneezing

• Coughing

• Nasal congestion

• Throat irritation

• Skin rashes

• Itchy eyes

• Watery eyes

• Wheezing

• Shortness of breath

• Headaches

• Fatigue

• Sinus infections

• Asthma attacks

• Allergic reactions

• Respiratory infections

Top 11 Common Causes of Mold Growth

Mold growth is a prevalent issue in many homes. Understanding the causes can help you strategically prevent mold infestation, and maintain a healthier indoor living environment.

So, now that we know the types of mold, let’s discuss what causes mold on walls.

Water Leaks in Foundation

Water leaks in foundations are a primary cause of mold growth in basements and lower levels of a home.

Foundation often has cracks or gaps in case of improper construction or inadequate repair. When groundwater seeps through these gaps, the moisture provides an ideal environment for mold spores to thrive.

Therefore, it is vital to make sure your foundation is properly sealed and undergoes regular inspections to check for any leaks. Additionally, maintaining proper drainage around your home's foundation is also crucial as it can direct water away from the structure, reducing the risk of leaks and subsequent mold growth.

Cracks in Walls

Cracks in walls, whether due to structural issues, or natural settling of the building, can allow moisture to enter your home. These cracks can be caused by a variety of factors, including poor construction, ground movement, or extreme weather conditions.

When moisture enters through these cracks, it accumulates behind the walls, creating a perfect environment for mold to grow.

Regular inspection of walls, and prompt repair in case of cracks is therefore important to prevent moisture intrusion and mold growth.

Leaking Roofs

Leaking roofs are another common cause of mold growth, particularly in attic spaces, and upper levels of a home. They are caused by damaged or missing shingles, improperly installed flashing, or clogged gutters.

When water backs up under the roofing material, it infiltrates the roof structure, seeps into walls and ceilings, and provides moisture for mold colonies to establish.

Regular roof maintenance, and cleaning the gutters can help avoid the problem.

Leaky Water Pipes

Leaky water pipes, whether hidden within walls or exposed, are a common cause of moisture that leads to mold growth.

These leaks can be caused by corroded pipes, loose connections, or high water pressure. Since they occur within walls, they can go unnoticed for extended periods of time, which allows mold to flourish in hidden areas.

Poor Construction of Walls

Poor construction practices can contribute to mold growth by allowing moisture to penetrate and accumulate within wall cavities.

Inadequate waterproofing allows water to seep into the walls, while improper insulation can lead to condensation buildup. A simple solution is to use moisture-resistant materials and ensure proper construction techniques to mitigate the risk of mold growth.

High Humidity

High indoor humidity, typically above 55%, creates a conducive environment for mold growth. This is especially true in bathrooms, kitchens, and laundry rooms where there is moisture.

Other than natural climatic conditions, poor ventilation, and excessive use of humidifiers, can also contribute to high humidity. Using high-quality dehumidifiers, ensuring adequate ventilation, and controlling indoor humidity levels through proper air conditioning can help control moisture levels and prevent mold growth.

Poor Ventilation

Poor ventilation is another common cause of mold growth. It prevents the effective removal of moisture from inside the house, especially from areas like basements, bathrooms, and kitchens where moisture levels are relatively higher.

Installing exhaust fans, opening windows, and having functioning HVAC systems inside the house can improve ventilation and reduce the risk of mold.

Damp Basements

Basements are naturally darker, cooler, and more humid, which is why they are considered a breeding ground for mold. Apart from naturally favorable conditions from mold growth, basements are also susceptible to high moisture content because of the risk of groundwater seepage, poor ventilation, or leaking pipes.

This moisture leads to mold growth on walls, floors, and stored items.

Crawl Spaces

Crawl spaces, similar to basements, can harbor mold due to their often damp and poorly ventilated conditions. Moisture in crawl spaces can come from the ground, leaking pipes, or high-humidity mold growth.

Properly sealing and insulating these spaces, and installation of vapor barriers can help avoid mold problems.

Flood

Flooding introduces a large amount of water into a home, creating an ideal environment for mold growth. Whether caused by natural disasters, plumbing failures, or overflowing appliances, flooding saturates walls, floors, and furnishings.

On top of that, even after the visible water is removed, moisture can remain trapped in materials, which leads to excessive mold growth. Thoroughly drying all affected areas after a flood is, therefore, crucial to prevent mold.

Mold inspection services often offer professional water damage restoration that ensures the moisture is effectively removed, so that there is minimal mold growth.

Humidifiers

Humidifiers are often used to improve indoor air quality. However, in case of improper maintenance, they can also inadvertently contribute to mold growth. Since the machine adds moisture to the air, it can excessively raise humidity when overused or malfunctioning.

For example, faulty humidistat can lead to unintentional over-humidification. Similarly, the use of mineral water in the humidifier tank leaves behind a residue that clogs the tank and facilitates mold growth. A dirt filter or old water reservoir can also cause the problem.

Regularly cleaning and maintaining humidifiers, and diligently monitoring indoor humidity levels can prevent humidifiers from becoming a source of mold growth.

Prevention of Mold on Walls

Here’s how you can prevent mold growth:

• Regular Inspections: Regularly check for mold growth in homes, especially focusing on areas like basements, and bathrooms as they are prone to moisture. Look for signs of mold, such as musty odors or visible spots on walls and ceilings. Also check for leaks in roofs, pipes, and walls, and get professional help to promptly address any issues.
• Dehumidifiers: Use high-quality dehumidifiers to maintain indoor humidity levels below 60%.
• Adequate Ventilation: Ensure adequate ventilation through exhaust fans and opening windows.
• Mold Resistant Products: Use of mold-resistant products like fiberglass insulation, and EPA-approved fungicides can resist mold growth.

Get a Professional Mold Inspection

Mold on walls is a common yet preventable issue. The 11 factors highlighted in the article can help you identify the root cause so that you can take proactive measures to maintain a mold-free environment.

While home checks are important, professional mold inspection can evaluate more thoroughly, identify hidden mold sources, and provide tailored solutions.

MI&T is a reputable company offering mold inspection and treatment services, and we can help you ensure a healthy indoor environment free of infestation.

Prioritize a healthier living space for you and your family, and contact us today!

Frequently Asked Questions

How often do I need a mold inspection?

Mold inspection is important at least once a year. However, if you have the following risk factors, you might need more frequent home checks:

• Moved into an old, previously unoccupied home
• Live in a humid climate
• Recently experienced flooding
• Are experiencing allergy-like symptoms