Beat the Humidity: Your Property Manager's Guide to Mould Prevention This Autumn

Paulina Ramirez
Oct 7, 2025
5 min read

What You Will Learn In This Article:

Why Mould Grows in Humid Weather: Understand how increased moisture in the air creates ideal conditions for mould to thrive.

Simple Ways to Prevent Mould: Learn practical steps like controlling indoor humidity, ensuring good ventilation, and quickly drying wet areas.

Importance of Fixing Leaks: Discover why even small leaks can lead to big mould problems and need immediate attention.

How to Maintain Your Property's Exterior: Get tips on keeping gutters clear and ensuring proper drainage to protect your building.

When to Call Professionals: Know when a mould problem is too big to handle yourself and when it's time to seek expert help.

As the crisp autumn air returns, we often welcome the cool breeze and vibrant colours. But for property managers and building owners, the change in seasons brings a less welcome challenge: the heightened risk of mold growth. During the damp autumn months, commercial and multi-unit residential facilities can become prime breeding grounds for mould, potentially leading to health concerns for occupants, lingering unpleasant odours, and even significant structural damage if left unaddressed.

Why Humidity is Mould's Best Friend in Your Buildings

Mould is a type of fungus that thrives in damp, dark, and warm environments. It reproduces by releasing tiny spores into the air, which are naturally present almost everywhere. When these microscopic spores land on a wet surface and find a food source (like wood, drywall, fabric, or even dust), they can quickly begin to grow and spread.

As the temperatures drop, moisture still poses a significant risk. The cool autumn air can cause a phenomenon known as condensation, where moisture suspended in the air turns back into a liquid when it comes into contact with colder surfaces. This is a common issue on windows, pipes, and other surfaces in your properties. Think about the dampness in less-ventilated areas like basements, mechanical rooms, or even inside wall cavities—these are the perfect places for mold colonies to start if not managed effectively. For property managers, understanding these common culprits is the first step in protecting your investments and your tenant's well-being.

Simple Steps for a Mould-Free Property

The excellent news is that by implementing a few proactive and consistent steps, you can significantly reduce the risk of mould growth across your residential or commercial portfolio.

Control Indoor Humidity Levels Rigorously: 
This is your most powerful defence! Aim to maintain indoor humidity levels below 60%, ideally between 30% and 50%, throughout your buildings.

Strategic Dehumidifier Use: Deploy industrial-grade dehumidifiers in naturally damp areas like basements, underground parking garages, storage units, and laundry rooms. Ensure regular maintenance and emptying schedules.

Optimize HVAC Systems: Program and maintain your building's HVAC systems to not only cool but also effectively remove moisture from the air. Regular filter changes are crucial for efficient operation.

Monitor Key Areas: Utilize hygrometers (humidity gauges) in various units and common areas to continuously monitor humidity levels, allowing for quick adjustments.

Ensure Comprehensive Ventilation: 
Good airflow is paramount to prevent moisture from lingering and becoming stagnant.

Promote Exhaust Fan Use: Educate tenants and staff on the importance of consistently using exhaust fans in bathrooms during and after showers, and in kitchens while cooking. Ensure these fans are properly vented to the outside, not into attics or wall cavities.

Maintain Common Area Airflow: Ensure ventilation systems in hallways, stairwells, and shared amenities are functioning optimally to prevent stale, humid air from settling.

Address Blocked Vents: Conduct regular checks to ensure air vents in units and common areas are not obstructed by furniture, storage, or décor, which can trap moisture.

Address All Leaks Promptly and Thoroughly:
Even the smallest, seemingly insignificant leak can become a major mould problem if ignored.

Immediate Repairs: Establish a rapid response protocol for repairing leaky pipes, roofs, windows, and foundation cracks as soon as they are reported or discovered.

Regular Inspections: Implement a schedule for routine inspections of plumbing, roofing, and building envelopes, especially before and after periods of heavy rain or snowmelt.

Condensation Management: Insulate cold pipes in basements, mechanical rooms, and utility closets to prevent condensation buildup that can lead to chronic dampness.

Clean and Dry Wet Areas Rapidly:
When water intrusion occurs, swift action is critical.

Rapid Response Protocols: Train staff or engage professional services for immediate response to floods, major spills, or water damage incidents.

Thorough Drying: Ensure all wet surfaces, including carpets, subflooring, walls, and upholstery, are thoroughly dried within 24-48 hours of becoming wet. This timeframe is crucial to inhibit mould growth.

Post-Cleaning Drying: After any significant cleaning or maintenance that involves water, ensure the area is completely dry before sealing it or allowing normal use.

Maintain Exterior Drainage Systems: 
Proper exterior drainage is vital to keep water away from your building's foundation and interior.

Clear Gutters and Downspouts: Regularly inspect and clean gutters and downspouts to ensure they are free of debris and directing water effectively away from the building.

Proper Grading: Verify that the landscaping and ground around your foundation slope away from the building to prevent water pooling against exterior walls.

Proactive Monitoring of High-Risk Areas:
Basements, crawl spaces, and attics are often prone to dampness and require extra vigilance.

Scheduled Inspections: Periodically inspect these areas for any signs of moisture, water stains, or musty odours.

Vapour Barriers: Consider installing or maintaining proper vapour barriers in crawl spaces to prevent ground moisture from migrating into the building envelope.

Woman questioning why mould keeps growing on her wall

When to Call the Professionals: Your Trusted Partner

While these preventative measures are highly effective for day-to-day management and addressing minor issues, mould can sometimes become a larger, more complex problem. As property managers, it's crucial to know when to bring in the experts. If you discover mould covering a significant area (more than a few square feet), if it's found within your HVAC system, or if tenants or occupants are experiencing persistent health symptoms that could be linked to mould exposure, it's time to call in certified restoration professionals. Attempting to clean large mould infestations yourself or having untrained staff do so can inadvertently spread spores, worsen the contamination, and create further liabilities.

How ARS Responds Canada Can Help Your Portfolio Thrive

At ARS Responds Canada, we deeply understand the unique challenges property managers face with mould, especially during humid months. We are your dedicated partner in maintaining healthy and safe environments across your commercial and industrial facilities. Our certified professionals are equipped with the expertise, advanced technology, and streamlined processes to:

Comprehensive Assessment & Identification: We thoroughly inspect your properties to pinpoint the source of moisture, accurately assess the extent of mould growth, and identify hidden contamination.

Safe & Effective Remediation: Our team follows rigorous industry best practices and safety protocols to safely remove mould, prevent cross-contamination to unaffected areas, and restore affected materials and structures efficiently.

Proactive Prevention Strategies: Beyond remediation, we provide tailored recommendations and implement solutions to address the underlying moisture issues, helping you prevent future mould problems and protect your assets long-term. This includes advising on ongoing humidity control and ventilation improvements.

Minimize Tenant Disruption & Liability: We work efficiently and discreetly to minimize disruption to your tenants and operations, ensuring clear communication throughout the process and helping you mitigate potential liabilities associated with mould.

Don't let mould compromise your properties or the well-being of your occupants this autumn. By staying proactive and knowing when to call for expert help, you can ensure a healthier, more comfortable, and more valuable environment for your tenants and clients.