Why NYC Window Lintels Fail
Window lintels are the horizontal structural elements — typically steel angle iron — that carry the weight of brick above window and door openings. In NYC pre-war buildings, these were installed without galvanizing or corrosion protection. Moisture infiltrates through mortar joints, reaches the steel, and begins oxidation.
Rust doesn't just weaken steel — it expands it. A corroded lintel can expand to 8–10 times its original volume, pushing outward against surrounding brick. The result is the classic stair-step crack pattern following mortar joints diagonally upward from window corners. By the time these cracks are visible, the lintel is typically severely compromised.
What We Replace Lintels With
We replace failed steel lintels with hot-dip galvanized steel angle iron — same structural profile as the original, with a zinc coating that prevents oxidation for 50+ years. For landmark properties, we use appropriately sized galvanized lintels consistent with LPC requirements.
Lintel Replacement Process
- Temporary shoring installed above the opening before any brick removal
- Remove brick courses above existing lintel to expose full bearing length
- Remove corroded lintel completely
- Clean bearing surfaces; patch deteriorated mortar in bearing zone
- Install new galvanized angle iron lintel with full bearing on both sides
- Rebuild brick courses above lintel in original configuration
- Repoint all disturbed mortar joints
- Remove temporary shoring after 7-day cure
DOB Considerations for Lintel Replacement
Lintel replacement is generally considered a repair and typically does not require a DOB permit for 1–3 family buildings. Multi-family buildings (4+ units) may require a DOB filing. Landmark properties require LPC approval. We assess permit requirements for every project before submitting an estimate.