Houston Heat: Is New Siding Brewing Lung Mold?

By Franklin Everett Shaw

February 25, 2026

The musty smell. It’s faint at first, almost unnoticeable. But then it grows, clinging to the air, a constant reminder of something unseen, something unwelcome. For Houston homeowners, that smell can be the harbinger of lung mold, a serious health threat that can be exacerbated by the very thing meant to protect their homes: siding.

Houston’s humid climate is a breeding ground for mold. Add to that the potential for improper siding installation, and you’ve got a recipe for disaster. This isn’t just about aesthetics; it’s about your health, your family’s well-being, and the structural integrity of your home. Let’s dive into how to protect yourself.

Understanding the Threat: Mold and Houston’s Humidity

Houston’s average humidity hovers around 75%, creating the perfect environment for mold to thrive. Mold spores are everywhere, but they need moisture and organic material (like wood or drywall) to grow. Poorly installed siding can trap moisture, creating a dark, damp haven for mold colonies to flourish, potentially leading to lung mold issues.

Lung mold, specifically, refers to molds that can cause respiratory problems when their spores are inhaled. Aspergillus, Cladosporium, and Stachybotrys chartarum (black mold) are common culprits. These molds can trigger allergic reactions, asthma attacks, and even more serious infections, especially in individuals with weakened immune systems.

Siding Installation: The First Line of Defense

Proper siding installation is paramount in preventing moisture intrusion. This isn’t a DIY project for the faint of heart. Here’s what a professional installation should entail:

• Proper Flashing: Flashing is a thin material (usually metal or plastic) installed to prevent water from penetrating joints and seams. It’s crucial around windows, doors, roof intersections, and any other area where water can easily enter. Many contractors skip or improperly install flashing to save time and money. This is a critical mistake.
• Weather-Resistant Barrier (WRB): A WRB, like Tyvek or similar products, is a membrane installed beneath the siding to protect the sheathing from water damage. It allows moisture vapor to escape from inside the house while preventing liquid water from entering. Overlapping the WRB correctly is essential; improper overlap creates weak points.
• Proper Nailing: Over-nailing or under-nailing siding can cause problems. Over-nailing restricts the siding’s ability to expand and contract with temperature changes, leading to buckling and cracking. Under-nailing leaves the siding vulnerable to wind damage and moisture penetration.
• Ventilation: Adequate ventilation behind the siding is crucial for drying out any moisture that does get in. This often involves installing furring strips to create an air gap between the siding and the WRB. Many older homes in neighborhoods like the Heights or Montrose lack proper ventilation, making them particularly susceptible to mold issues after siding replacement.

Recognizing the Signs: Mold-Related Symptoms and Home Inspection

Early detection is key to preventing a full-blown mold infestation. Be vigilant and watch for these signs:

• Musty Odor: As mentioned earlier, a persistent musty odor is a telltale sign of mold growth. Don’t ignore it, even if you can’t see any visible mold.
• Visible Mold: Look for discoloration or staining on walls, ceilings, or around windows and doors. Mold can appear in various colors, including black, green, brown, or white. Check areas prone to moisture, such as bathrooms, kitchens, and basements (if applicable).
• Water Stains: Water stains on walls or ceilings indicate a leak, which can lead to mold growth. Investigate the source of the leak and repair it promptly.
• Health Symptoms: Mold exposure can cause a range of symptoms, including:
  • Coughing
  • Wheezing
  • Sneezing
  • Runny nose
  • Sore throat
  • Headaches
  • Fatigue
  • Skin rashes

If you suspect mold, consider hiring a certified mold inspector. They can conduct air and surface samples to identify the type and extent of the mold growth. A professional inspection is especially important after siding installation to ensure no moisture issues were created during the process.

Mold Remediation: Taking Action

If you find mold, don’t panic. Small areas of mold (less than 10 square feet) can often be cleaned yourself using a solution of bleach and water (1 part bleach to 10 parts water). Always wear gloves, a mask, and eye protection when cleaning mold.

For larger infestations, it’s best to hire a professional mold remediation company. They have the expertise and equipment to safely and effectively remove mold and prevent it from returning. Look for companies certified by organizations like the Institute of Inspection, Cleaning and Restoration Certification (IICRC).

Choosing Mold-Resistant Siding Materials

Selecting the right siding material can significantly reduce the risk of mold growth. Consider these options:

• Fiber Cement Siding: Fiber cement is a durable and fire-resistant material that is also resistant to mold and pests. It’s a popular choice in Houston due to its ability to withstand the harsh climate. However, proper installation is still crucial to prevent moisture intrusion.
• Vinyl Siding: Vinyl siding is another affordable and low-maintenance option that is resistant to mold and mildew. Look for vinyl siding with a built-in moisture management system to further protect your home.
• Engineered Wood Siding: Engineered wood siding is treated to resist moisture and decay. It offers the look of real wood without the same susceptibility to mold and pests.
• Avoid Wood Siding (Unless Properly Treated): Traditional wood siding is highly susceptible to mold and rot, especially in Houston’s humid climate. If you choose wood siding, ensure it’s properly treated with a preservative and regularly maintained.

Ensuring Proper Ventilation: A Crucial Step

Ventilation is often overlooked but is critical for preventing moisture buildup behind the siding.

• Furring Strips: As mentioned earlier, furring strips create an air gap between the siding and the WRB, allowing air to circulate and dry out any moisture.
• Vented Soffits and Fascia: Vented soffits and fascia allow air to enter the attic, which helps to regulate temperature and humidity levels. This can prevent condensation from forming on the underside of the roof and spreading to the siding.
• Regular Inspections: Inspect your siding and ventilation system regularly for any signs of damage or blockage. Clear any debris from vents to ensure proper airflow.

Case Study: The Heights Bungalow

A homeowner in the Heights neighborhood of Houston recently replaced their original wood siding with fiber cement siding. However, within a year, they noticed a musty odor and visible mold growth on the interior walls. An inspection revealed that the contractor had failed to install proper flashing around the windows and doors, allowing water to penetrate the wall cavity. The lack of ventilation behind the siding further exacerbated the problem. The homeowner had to hire a mold remediation company to remove the mold and then pay another contractor to properly install the flashing and ventilation system. This costly mistake could have been avoided with proper planning and oversight.

Common Mistakes and How to Avoid Them

• Hiring the Cheapest Contractor: Don’t sacrifice quality for price. Choose a contractor with a proven track record and positive reviews. Ask for references and check their licensing and insurance.
• Ignoring Warning Signs: Don’t dismiss a musty odor or water stain. Investigate the source and take action promptly.
• Improper DIY Repairs: If you’re not experienced in siding installation or mold remediation, leave it to the professionals. Improper repairs can worsen the problem and create further damage.
• Neglecting Maintenance: Regularly inspect your siding and ventilation system for any signs of damage or blockage. Clean gutters and downspouts to prevent water from pooling around the foundation.

Conclusion: Protecting Your Houston Home

Protecting your Houston home from lung mold after siding installation requires a proactive approach. By understanding the risks, choosing the right materials, ensuring proper installation and ventilation, and being vigilant for signs of mold, you can safeguard your health and the value of your property. Don’t let Houston’s humidity get the best of you. Take control and create a healthy and safe living environment for yourself and your family.