Brick is a durable and time-tested material in construction. It weathers storms and adds beauty to residential and commercial buildings. Despite its toughness, brick is not waterproof.
Efflorescence, freeze-thaw cracks, mold, mildew, and internal wall damage all trace back to one thing – water getting in and staying in. That’s why moisture management is not just an optional detail. It’s central to building longevity and occupant comfort.
Understanding how water behaves in and around brick structures can help prevent many common masonry failures.
Let’s take a closer look at the four key defenses every brick wall needs: flashing, weep holes, drainage planes, and attention to detail.
Flashing: Your First Line of Defense
Flashing is an essential component in a moisture management system. It redirects water from areas such as windows, wall bases, and tops of openings. Flashing is installed wall cavity and must be continuous, properly lapped, and sloped to shed water outward.
Metal flashing, peel-and-stick membranes, and composite products are all common choices, each with its own place depending on the project. What matters most is how the flashing is installed.
Improper flashing is a leading cause of moisture problems in brick walls. When it’s missing, poorly lapped, or installed flat rather than sloped, water collects behind the wall instead of draining out. Moisture can saturate insulation, rot wood framing, or cause freeze-thaw expansion in cold climates.
Every brick structure needs flashing at window heads, sills, wall bases, and roof intersections. Without it, gravity works against you.
Weep Holes: Small Gaps with a Big Job
Weep holes are the small, intentional openings you see at the base of a brick wall or above openings. They’re designed to allow water that collects behind the brick to escape. Without them, water has no exit path and remains trapped inside the cavity.
They may seem insignificant, but these tiny openings play a huge role in wall performance. They reduce pressure buildup, allow for drainage, and enable the wall cavity to dry out over time.
Weep holes must be spaced consistently, kept clear, and paired with clean cavity construction. Mortar droppings that clog the base of the wall can render weep holes useless. That’s why many modern installations include cavity nets or mesh products that keep the drainage path open during and after construction.
Drainage Planes: Moving Moisture Away from the Wall
Behind the brick veneer is where most of the moisture control happens. A well-built wall includes a drainage plane—a surface designed to carry water down and out of the wall system.
This typically takes the form of a water-resistive barrier (WRB) applied to the sheathing behind the air space. The WRB is often a building wrap, fluid-applied membrane, or rigid panel system. Its job is to keep the structural wall dry while allowing any trapped moisture to move downward and exit through the weep holes.
The air space itself, typically one inch or more, allows water to flow freely and also promotes drying. Without it, moisture can get absorbed directly into the sheathing or insulation.
Efflorescence and Mold: Signs Something’s Gone Wrong
Efflorescence is a white, powdery substance appearing on brick surfaces, when water carries dissolved salts to the surface. Once the water evaporates, the salts are left behind. It’s a cosmetic issue, but also a clue. If efflorescence appears regularly, it’s a sign that water is entering the wall system and attempting to escape.
Mold and mildew, on the other hand, signal deeper trouble. Moisture trapped within a wall can create ideal conditions for microbial growth. This is more common in residential settings where vapor barriers are installed incorrectly or where poor ventilation compounds the problem.
The best prevention strategy is keeping the wall dry in the first place. That means correctly installed flashing, functioning weep holes, and a drainage plane that works.
Attention to Detail: The Contractor’s Role
Even the best products can fail if not installed correctly. Moisture management in brick masonry isn’t about using one special component. It’s about how each part works together—brick, mortar, cavity, flashing, and drainage.
It also depends on the climate. In Michigan, where Primo Contracting operates, freeze-thaw cycles are a serious concern. Water inside a wall that freezes expands, causing cracks. Over time, this can lead to spalling bricks, broken joints, and expensive repairs.
The most effective defense is a contractor who understands how water moves through a wall and how each piece contributes to moisture control. Every cut, seal, lap, and fastener matters. Small mistakes, especially around penetrations or openings, become bigger problems over time.
Primo Contracting in Rochester Hills Builds for the Long Haul
Brick has been trusted for centuries, but it relies on modern moisture management to perform optimally. Without a system to drain, vent, and dry the wall cavity, even high-quality brick can lead to high-cost issues. At Primo Contracting, our masonry construction pros bring decades of experience to every project, from brick and block walls to chimney repair, custom home masonry, and more.
Our team builds with durability in mind, ensuring that every layer – from the first course to the last detail, is designed to withstand the elements. If you’re planning a new build or restoring an older structure, we’re here to ensure your brickwork not only looks good but also stays dry and sound for years to come.