Brick is often thought of as a solid, impenetrable building material, but in reality, it is naturally porous. While this characteristic allows masonry walls to breathe, it also means moisture can find its way inside if the system isn’t properly maintained. In Toronto’s climate, where rain, snow, humidity, and freeze-thaw cycles are common, moisture intrusion is one of the leading causes of masonry deterioration.
Understanding how water enters brick walls is the first step toward preventing long-term damage. With the right preventative measures and timely repairs, homeowners can protect their masonry and avoid costly structural issues.
The Porous Nature of Brick and Mortar
Brick and mortar are designed to absorb and release small amounts of moisture. This process helps regulate temperature and humidity within the wall system. Problems arise when water enters faster than it can escape or when it becomes trapped inside the masonry.
Mortar joints are especially vulnerable, as they are softer and more absorbent than the bricks themselves. Over time, exposure to rain, snow, and condensation can weaken mortar, creating gaps that allow water to penetrate deeper into the wall. Once moisture enters the system, it can migrate through the masonry and cause damage far beyond the surface.
Cracks and Deteriorated Mortar Joints
One of the most common entry points for moisture is cracked brickwork or deteriorating mortar joints. Small hairline cracks may seem harmless, but they can allow water to seep into the wall during heavy rain or melting snow. As temperatures drop, that trapped moisture freezes and expands, widening the cracks and accelerating damage.
Receding or crumbling mortar joints are another major concern. When mortar begins to erode, it loses its ability to protect the wall, making it easier for water to infiltrate. Over time, this can lead to loose bricks, interior dampness, and even structural instability.
Poor Drainage and Flashing Issues
Moisture problems often start not with the brick itself, but with how water is managed around the home. Blocked gutters, short downspouts, or improper grading can allow water to collect near brick walls and foundations. When water repeatedly pools against masonry, it increases the likelihood of absorption and long-term deterioration.
Flashing failures are another major source of moisture intrusion. Flashing is designed to redirect water away from vulnerable areas such as chimneys, roof intersections, windows, and doors. When flashing is damaged, improperly installed, or missing altogether, water can enter the wall system unnoticed and cause hidden damage behind the brick face.
Efflorescence as a Warning Sign
Efflorescence appears as a white, powdery residue on the surface of brick walls. While it may seem like a cosmetic issue, it is often a sign that moisture is moving through the masonry and carrying soluble salts to the surface. Efflorescence itself doesn’t usually cause damage, but it signals an underlying moisture problem that should not be ignored.
Repeated efflorescence indicates that water is consistently entering the wall system. Without intervention, the same moisture movement can weaken mortar joints and contribute to freeze-thaw damage.
How to Stop Moisture from Entering Brick Walls
Preventing moisture intrusion starts with regular inspections and proactive maintenance. Addressing small cracks and repointing deteriorated mortar joints helps restore the wall’s protective barrier and limits water entry. These repairs also allow the masonry to continue breathing properly without trapping moisture inside.
Improving drainage around the home is equally important. Ensuring gutters and downspouts are clear and directing water away from the foundation reduces prolonged exposure to moisture. Proper grading around the property can further prevent water from pooling near brick walls.
In some cases, applying a breathable masonry sealant can offer additional protection. These sealants repel surface water while still allowing moisture vapor to escape, reducing the risk of trapped water within the wall system. It’s essential that the correct type of sealant is used, as improper products can do more harm than good.
Protecting Your Masonry for the Long Term
Moisture intrusion is one of the most damaging forces acting on brick walls, but it’s also one of the most preventable. By understanding how water enters masonry and taking steps to address vulnerabilities early, homeowners can significantly extend the lifespan of their brickwork and avoid extensive repairs.
If you’ve noticed cracking, staining, efflorescence, or interior signs of moisture, it’s important to have your masonry professionally evaluated. For expert assessment and repair solutions tailored to Toronto’s climate, contact Turnbull Masonry today. Their experienced team can identify the source of moisture intrusion and restore your brick walls with lasting, professional results.