Moisture is the primary enemy of brick masonry - not in the dramatic sense of a single catastrophic event, but in the slow, compounding sense of water working its way into porous materials through every available opening, cycling through freeze and thaw, carrying dissolved salts to the surface, and progressively weakening the mortar joints and brick units that hold the wall together. In Michigan's climate, where freeze-thaw cycling is a seasonal constant and sustained rainfall and humidity are routine, moisture management isn't optional maintenance - it's the foundation of keeping a brick exterior performing for decades. Here's how to do it effectively.
1. Inspect and Repair Cracks and Deteriorated Mortar
Why it’s important:
Cracks in brick units and eroded mortar joints are the primary moisture entry points in any brick wall. Once water penetrates those openings, it reaches the more porous interior material - and in a Michigan winter, water inside the wall means freeze-thaw expansion pressure that widens the original crack and opens new ones. The damage is self-compounding: each freeze-thaw cycle leaves the material more porous and more susceptible to the next one.
How to prevent moisture damage:
Inspect brick walls in early spring - after freeze-thaw season has run its course - and again in late fall before winter arrives. Hairline cracks in mortar joints that haven't yet eroded below the brick face can be addressed with masonry caulk as a near-term measure, but properly matched repointing is the durable solution. Larger cracks, widespread mortar erosion, or cracks in a pattern that suggests foundation movement warrant professional assessment before repair work begins.
2. Ensure Proper Drainage Around Your Home
Why it’s important:
Water that pools at the base of a brick wall maintains sustained moisture contact with the foundation and the lowest courses of masonry - exactly the conditions that drive progressive mortar erosion and moisture infiltration into the wall assembly. Poor site drainage also saturates the soil against the foundation, increasing hydrostatic pressure that pushes moisture through the wall from the exterior face inward.
How to prevent moisture damage:
Gutters and downspouts should discharge water at least six feet from the base of the home - closer discharge points direct roof runoff directly against the foundation. Site grading that slopes away from the structure keeps surface water moving away rather than pooling. Properties with chronic drainage problems benefit from a French drain or equivalent solution installed to intercept water before it reaches the wall base. These are among the highest-return moisture management investments available because they address the volume of water reaching the masonry rather than just its effect.
3. Apply a breathable masonry sealant
Why it’s important:
A penetrating masonry sealant reduces moisture absorption at the brick and mortar surface - the first stage of the infiltration process. The breathable specification is what distinguishes a protective sealant from a damaging one: a breathable penetrating sealant reduces new moisture entry while allowing moisture already within the wall to escape as vapor. A film-forming sealant that blocks moisture escape traps water within the wall and accelerates the freeze-thaw damage it was meant to prevent. For a deeper look at how sealants work and what to look for in product selection, our guide on The Role of Masonry Sealants in Protecting Brickworkrole of masonry sealants in protecting brickwork covers the full picture.
How to prevent moisture damage:
Apply a high-quality breathable masonry sealant by sprayer or roller, working methodically across the full wall surface and giving particular attention to areas with significant weather exposure - south and west faces, areas below gutters and downspouts, and sections adjacent to grade. Most sealant manufacturers recommend reapplication every three to five years; the actual interval depends on exposure conditions and the specific product used.
4. Clean Your Brickwork Regularly
Why it’s important:
Dirt accumulation, biological growth, and efflorescence deposits on brick surfaces trap moisture against the face and can accelerate the surface erosion of both brick and mortar. Mold and algae growth in particular retain moisture and create conditions that sustain further biological activity - a wet surface stays wet longer than a clean one.
How to Prevent moisture damage:
A soft brush or low-pressure water wash removes surface deposits without the risk of driving water deeper into the masonry or damaging softer historic brick faces that high-pressure washing can erode. Efflorescence - the white powdery salt deposits that indicate moisture movement within the wall - responds well to a dilute water and white vinegar solution applied with a brush. Avoid cleaning during temperature extremes: cold weather slows drying and can leave moisture within the wall heading into a freeze cycle, while hot direct sun causes rapid surface drying that can stress the masonry.
5. Avoid Using De-Icing Salts Near Brick Walls
Why it’s important:
Chloride-based de-icing salts - standard rock salt and many commercial ice melt products - cause two distinct types of damage to brick masonry. First, they're hygroscopic: they absorb moisture from the surrounding environment and maintain wet conditions at the masonry surface longer than the ice or snow they melted would have alone. Second, salt that migrates into the pore structure of brick and mortar crystallizes as it dries, exerting internal pressure that contributes to spalling and surface erosion - a mechanism that compounds the freeze-thaw damage already present in Michigan winters.
How to prevent moisture damage:
Sand provides traction without chemical damage and is the safest option for use adjacent to masonry. Calcium magnesium acetate (CMA) is a chloride-free de-icing product that melts ice effectively without the salt crystallization damage that chloride products cause. Whatever product is used near brick surfaces, rinsing the area after the ice event removes residue before it has time to migrate into the masonry.
6. Maintain Roof Overhangs and Flashing
Why it’s important:
Roof overhangs and properly installed flashing are the primary defenses against water running down wall faces from above. Failed or inadequate flashing at roof-wall intersections, chimney bases, and window and door heads is one of the most common sources of sustained moisture infiltration in brick walls - and one of the most frequently overlooked because the failure point is often not visible from grade.
How to prevent moisture damage:
Inspect flashing at all roof-wall intersections, chimney bases, and above window and door openings annually - and specifically after significant storm events. Flashing that has lifted, cracked, or separated from the adjacent masonry needs prompt repair. Overhangs that are inadequate to deflect water away from the wall face during driven rain may warrant extension if recurring moisture problems trace back to that exposure.
7. Insulate Interior Walls and Manage Indoor Humidity
Why it’s important:
Moisture infiltration in brick walls isn't exclusively an exterior problem. In cold weather, warm interior air carrying humidity contacts the cooler brick wall assembly and deposits moisture within it - a process called vapor drive that can introduce significant moisture into masonry from the interior. Poorly insulated walls allow this process to occur more extensively and sustain conditions within the wall that contribute to mortar deterioration and biological growth.
How to prevent moisture damage:
Interior wall insulation reduces the temperature gradient that drives vapor condensation within the wall assembly. Dehumidification during heating season - when indoor humidity is elevated by occupant activity against a backdrop of dry outdoor air - reduces the moisture load that vapor drive introduces. Adequate ventilation in high-humidity areas like kitchens, bathrooms, and basements prevents localized humidity spikes that concentrate the problem.
8. Avoid Planting Vegetation Too Close to Brick Walls
Why it’s important:
Vegetation in direct contact with or immediately adjacent to brick walls creates sustained moisture conditions at the wall surface - plants trap moisture, block airflow that would otherwise dry the surface between weather events, and maintain the wet conditions that accelerate both biological growth and mortar erosion. Root systems from shrubs and trees planted close to the foundation can also interfere with drainage and exert mechanical pressure on the foundation masonry.
How to prevent moisture damage:
Maintain a minimum clearance of two to three feet between vegetation and brick wall faces - enough to allow adequate airflow and prevent direct contact. Vines growing on brick walls are a particular concern; they create sustained moisture contact across the full wall surface and their attachment points can damage mortar joints as the growth expands. Trees and shrubs with aggressive root systems should be planted at distances sufficient to keep roots clear of the foundation.
9. Repair and Replace Damaged Bricks as Needed
Why it’s important:
Spalled, cracked, or otherwise compromised brick units absorb moisture significantly faster than intact ones - the damaged face or fractured body exposes the more porous interior material directly to weather. A damaged brick in a wall section doesn't just deteriorate on its own timeline; it introduces moisture conditions that accelerate mortar erosion and freeze-thaw damage in the surrounding intact bricks.
How to prevent moisture damage:
Annual inspection for spalling, surface fractures, and chips identifies damaged units while they're still isolated. Replacement with matched brick set in compatible mortar - handled by a professional mason who can source appropriate material and execute the repair without disturbing the surrounding masonry - eliminates the accelerated moisture entry point and restores the wall's uniform performance across the repaired section.
10. Schedule Regular Masonry Inspections
Why it’s important:
The most consistent characteristic of masonry moisture damage is that it's more advanced than it looks from the surface. Mortar that appears surface-eroded is often deeply deteriorated within the joint. Efflorescence that appeared recently reflects moisture conditions that have been present for a full season. Brick that looks intact may have internal fractures from freeze-thaw cycling that haven't yet expressed at the face. Professional inspection identifies the actual condition rather than the visible condition - and the gap between those two is often significant.
How to prevent moisture damage:
Annual professional masonry inspection - timed for early spring after freeze-thaw season - establishes the actual condition of mortar joints, brick units, flashing, and drainage, and identifies what maintenance or repair the coming season warrants. For older homes and properties in areas with significant seasonal weather exposure, this inspection investment consistently produces lower total maintenance costs than deferred assessment followed by reactive repair.
Final Thoughts
Moisture damage in brick masonry is predictable, progressive, and largely preventable with consistent attention to the conditions that drive it. Drainage, sealant maintenance, joint integrity, and surface cleanliness address the primary mechanisms through which moisture enters and damages brick walls. The masonry that performs well decade after decade is the masonry that receives that attention consistently - not the masonry that receives expensive intervention after extended neglect.
When moisture has already affected your brickwork - cracking mortar, spalling bricks, interior leaks, or visible structural change - early professional intervention is what stops the progression before it compounds further. Learn more about our Professional Brick Repair Servicesprofessional brick repair services to see how we identify moisture-related damage and restore masonry integrity before the problem worsens.
Contact Bethel Custom BrickContact Bethel Custom Brick today to schedule a thorough evaluation and get a clear picture of what your brick walls need to perform well through Michigan's seasons.
Bethel Custom Brick is a Metro Detroit masonry contractor serving homeowners across Southeast Michigan. Learn more about us.
