As you begin your journey of settling into life in Canada, one of the most important steps is finding the right place to live. Buying a home is a significant milestone, especially for newcomers, and understanding the risks in Canadian housing can help you make a smart, healthy decision. This way, you don’t have to worry about major purchases and can focus on the fun instead — all with the help of Canoo and Reactine! A proper home inspection testing for allergens and mould can save thousands of dollars in future repairs and medical costs.

This guide will help you understand common indoor allergens, hidden mould risks, and how to inspect a home before making an offer.

The Invisible Threat: Understanding Allergens and Mould in Canadian Homes

Common Household Allergens and Their Sources

Indoor allergens can trigger asthma and chronic respiratory issues. The most common allergens found in homes include:

Dust mites that thrive in carpets, bedding, and upholstery.
Pet dander from tiny skin flakes on cats, dogs, and other animals.
Pollen coming indoors on clothes, shoes, and through open windows.
Mould spores that grow in damp environments, like basements and bathrooms.

Types of Toxic and Non-Toxic Moulds in Homes

Mould is a common issue in Canadian homes. Not all mould is toxic, but certain types can cause serious health risks:

Toxic moulds like stachybotrys chartarum (more commonly known as black mould) produce mycotoxins, causing headaches, respiratory distress, and immune system issues.
Non-toxic moulds, like cladosporium, aspergillus, and penicillium, don’t sound as bad as the mould mentioned above, but can still trigger allergies and worsen asthma.

A person experiencing allergies. — Credit: Getty Images

Health Impacts of Prolonged Exposure to Indoor Allergens and Mould

Long-term exposure to allergens and mould can cause:

Chronic coughing, sneezing, and congestion.
Fatigue and headaches.
Severe respiratory infections in those with weakened immune systems.

Ways to Combat Household Allergens and Mould

Use a dehumidifier to maintain indoor humidity below 50 percent.
Ventilate bathrooms and kitchens to prevent moisture buildup.
Clean and replace air filters in HVAC systems regularly.
Inspect plumbing for leaks and repair water damage quickly.
Try using Reactine to manage allergy symptoms that may arise — as an antihistamine, Reactine provides fast and long-lasting relief.
Check out Reactine’s blog for more in-depth processes in combating household mould.

Limitations of Home Inspections in Canada

Standard home inspections typically focus on structural integrity, electrical systems, and plumbing, but they often overlook allergens and mould. Many inspectors do not check behind walls, under carpets, or in ventilation systems.

A person performing a home inspection. — Credit: Getty Images

Why Allergens and Mould Often Go Undetected

Mould can grow behind drywall and within insulation, making it difficult to spot without specialized equipment. Sellers may also paint over water stains to conceal past leaks, masking potential moisture issues. Additionally, microscopic allergens are not visible to the naked eye, making a thorough assessment essential before purchasing a home.

A professional mould and allergen inspection includes air quality testing for airborne mould spores and allergens, infrared moisture detection to find hidden leaks, and surface swab tests for identifying mould types.

Hiring a certified mould inspector can reveal hidden health hazards before you commit to a home purchase.

The Pre-Viewing Checklist: What to Bring and Look For

Before visiting a home, pack these essential tools to test areas for yourself:

Flashlight to examine dark corners, crawl spaces, and attic areas.
Camera to document potential problem areas for later review.
List of questions to ask about previous water damage, roof leaks, and basement flooding history.

Red Flag Home Inspection Checklist: During Home Viewing

Visual Indicators

Water stains on ceilings or walls.
Warped flooring or bubbling paint (signs of moisture).
Dark spots in grout, caulking, or drywall.

Smell Indicators

Musty, damp odours (especially in basements, attics, and crawl spaces).
Persistent pet or smoke smells.

Room-by-Room Inspection Checklist

Basement

Check for damp walls, condensation, or visible mould.
Look for foundation cracks that allow moisture entry.
Smell for mustiness (a sign of hidden mould).

Bathrooms

Inspect for mould around tubs, sinks, and showers.
Look for peeling paint or bubbling wallpaper.
Ensure ventilation fans work properly.

Kitchen

Check under sinks for leaks and water damage.
Look behind appliances for hidden mould.
Examine caulking and tile grout for black spots.

HVAC System

Ask about the last duct cleaning.
Inspect air filters and vents for dust accumulation.
Look for water damage around air conditioning units.

A home might look perfect on the surface, but hidden allergens and mould can pose serious health risks and lead to costly repairs. Investing in a thorough allergen and mould inspection before purchasing can save you on remediation and medical expenses.

People signing a document after a home inspection. — Credit: Faruk Tokluoğlu

FAQ: Your Questions About Home Inspection Answered

Can a house with mould ever truly be fixed? Yes, but proper mould remediation is necessary. This involves removing affected materials, improving ventilation, and addressing the moisture source to prevent regrowth in the future.

What is the difference between mould testing and mould inspection? Mould testing collects air and surface samples to identify mould types. Meanwhile, mould inspection includes a visual assessment and moisture detection to discover how fast the mould grows.

Are newer homes less likely to have allergen and mould issues? Not always. Modern homes are built to be airtight, which can trap moisture and allergens inside if ventilation is poor.

Additional Resources

This blog was developed in partnership with Reactine.