Masonry buildings are valued for their durability, but their strength relies on more than just brick and mortar. Hidden steel components—such as lintels, shelf angles, relief angles, and ties—play a crucial role in supporting masonry facades. However, when moisture infiltrates the structure, corrosion weakens these elements, leading to rust jacking, section loss, and displaced masonry.
A well-installed through-wall flashing system is essential in preventing water intrusion and protecting steel from deterioration. By redirecting moisture away from key structural components, these systems help extend the lifespan of a masonry facade.
How Steel Corrosion Affects Masonry Stability
Steel elements within masonry walls are especially vulnerable to moisture. Unlike masonry, which can handle some water absorption, steel reacts with oxygen and water, causing oxidation. Over time, this process leads to expansion, material loss, and a compromised structure.
Critical Failure Points in Masonry Corrosion:
- Rust Jacking – Expanding corroded steel exerts force on surrounding masonry, leading to cracks, bulging, and displacement.
- Pack Rust – Layers of rust accumulate between steel and adjacent materials, reducing load-bearing capacity.
- Section Loss – Corrosion causes thinning of the steel, weakening its ability to support masonry above.
- Displaced Masonry Veneer – As rusting steel distorts, bricks or stone can shift outward, creating misalignment and potential structural hazards.
If not addressed, these issues can accelerate deterioration, putting the building’s integrity at risk.
The Importance of Proper Through-Wall Flashing in Preventing Corrosion
Through-wall flashing is designed to channel water away from embedded steel elements, keeping them dry and structurally sound. A properly installed system consists of multiple components working together to protect against moisture intrusion:
- Self-Adhering Flashing Membranes – Prevents water from penetrating the masonry cavity.
- Sheet Metal Drip Edges – Guides water away from the building to reduce saturation.
- Termination Bars & Elastomeric Sealants – Secures flashing in place and prevents moisture bypass.
- Weep Ropes & Cavity Ventilation – Allows trapped moisture to escape instead of accumulating within the wall.
- End Dams – Ensures water is directed away from vulnerable areas rather than seeping into unintended locations.
Without an effective flashing system, trapped moisture accelerates steel corrosion and can lead to early structural failure.
Identifying Early Signs of Corrosion & Water Infiltration
Detecting corrosion and moisture issues early is key to preventing expensive repairs. Warning signs to watch for include:
- Cracks or movement near steel lintels and shelf angles
- Rust stains appearing on masonry surfaces
- Bulging or bowing brick veneer
- Step cracking, especially around windows and doors
- White, powdery efflorescence, which signals moisture buildup
Regular inspections help catch these issues before they turn into major structural concerns.
Why Routine Maintenance is Essential
Even the best-designed through-wall flashing systems require proper installation and ongoing maintenance to remain effective. Water infiltration can go unnoticed for years, gradually damaging embedded steel and weakening the facade.
Routine inspections should include:
- Checking for deteriorated sealants around masonry joints\
- Examining weep holes and cavity vents to confirm proper drainage
- Inspecting embedded steel for signs of rust and corrosion
- Ensuring flashing is sealed correctly and sloped for effective water runoff
By prioritizing regular inspections and moisture control, building owners can prevent costly structural failures and extend the life of their masonry facades.
Protecting Your Building’s Integrity
Masonry structures rely on more than just their outward appearance—hidden steel components play a crucial role in long-term stability. Steel corrosion is one of the most overlooked risks in building deterioration, but with a properly maintained through-wall flashing system, moisture can be managed effectively, preserving both the facade and its structural support.
For over 40 years, Building Restoration Corporation has been a trusted leader in masonry restoration, tuckpointing, and moisture management. We specialize in preserving commercial properties, historic landmarks, and large-scale masonry structures, ensuring long-term stability and protection.
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