Rust Jacking and Failing Masonry Lintels: What You Need to Know
Steel lintels—the hidden heroes above windows and doors—quietly support the weight of masonry walls. But over time, especially in older buildings without modern protective measures, these critical components can fall victim to a destructive force: rust jacking.
What is Rust Jacking?
Rust jacking occurs when steel lintels corrode. As steel oxidizes, it expands dramatically, delaminating into layers of rust. This expansion doesn't just weaken the lintel—it exerts powerful pressure on the surrounding masonry, causing visible and sometimes severe structural damage.
Warning Signs and Impacts:
Cracked or displaced masonry – Corrosion-driven expansion can push brickwork out of alignment or create visible cracks.
Compromised structural integrity – As steel deteriorates, the lintel’s ability to bear loads diminishes.
Increased water infiltration – Cracks invite moisture inside, accelerating deterioration, especially during freeze-thaw cycles.
Often, quick fixes like caulking or patching are used to hide the symptoms. Unfortunately, these stopgap measures can trap moisture inside the wall, speeding up both corrosion and masonry failure.
How is a Rusted Lintel Repaired?
When corrosion reaches a critical point, full lintel replacement is necessary. A proper repair involves:
Careful removal of the damaged lintel and 3–4 courses of brickwork above it.
Installation of a new hot-dipped galvanized steel lintel designed to resist future corrosion.
Integration of proper flashing to channel water safely out of the wall system.
Reconstruction of the masonry, using new bricks and expert repointing to match the existing façade.
Don’t Ignore the Signs
If you notice cracks, shifting bricks, or other signs of distress around your windows or doors, it’s time for a professional evaluation.
GRLA’s Building Envelope Science Division has the expertise to assess damage and recommend targeted, lasting solutions.
Contact GRLA today to protect your building—and its future.