Above every window and door in a brick wall there is a steel angle carrying the weight of the masonry above the opening. On most homes around Chicago it is a painted steel lintel, sitting in a spot that gets wet and stays wet.
When the paint film breaks down, the steel starts to corrode. As it corrodes it expands, to as much as ten times its original thickness. That force has nowhere to go except up, into the brickwork sitting on it.
How to spot it
The classic signs are a rust stain bleeding down the brick above a window, and a horizontal crack running along the joint just above the opening. Sometimes the brick course directly above the window has visibly lifted or stepped forward.
If you have rust staining but no cracking yet, you have caught it early, and the fix is smaller.
The repair
The masonry above the opening gets shored so it is fully supported before anything comes out. The corroded angle is removed, and a correctly sized galvanized or primed steel lintel goes in with proper bearing at each end.
The detail that matters is what goes above the new steel: flashing, and weep holes. Water that gets into the wall needs somewhere to drain out. Without flashing and weeps, water sits on the lintel and the new steel starts the same process over again. A surprising number of original installations skipped this entirely, which is exactly why the original lintel failed.
Then the brick is reset, the joints are repointed to match, and we clean the rust staining off the surrounding brick as far as it will come.
Signs you need this work
- Rust stains bleeding down the brick above a window
- A horizontal crack running along the top of a window or door
- Brick above an opening that has lifted or stepped out of line
- Visible flaking rust on the steel angle
- Mortar joints above the window opening up
- Windows that have become hard to operate
What's included
- Temporary shoring of the masonry above the opening
- Removal of the corroded steel angle
- New galvanized or primed steel lintel, correctly sized and bearing
- Flashing and weep holes installed above the lintel
- Brick reset and repointed to match
- Rust staining cleaned from surrounding brick where possible
How we do it
- 1
Confirm the cause
Rust stains and a horizontal crack above an opening are the tell. We check bearing and span before quoting.
- 2
Shore the opening
The brickwork above gets properly supported before anything is removed. This is not a step to improvise.
- 3
Swap the steel
Corroded angle out, new galvanized steel in, sized for the span with proper bearing on each end.
- 4
Flash and rebuild
Flashing and weeps go in above the lintel so water drains out instead of sitting on the steel, then the brick is reset and repointed.
Common questions
What is a lintel?
The steel angle that carries the brickwork above a window or door. On most Chicago-area homes it is a painted steel angle, and paint does not last forever.
Why does rust crack the brick?
Steel expands to several times its original thickness as it corrodes. That expansion happens inside a wall that has nowhere to go, so it lifts the brick above it and cracks the joints. It is called rust jacking.
Can a rusted lintel just be painted?
If it is surface rust caught early, cleaning and coating it can buy years. Once it has delaminated or started lifting the brick, it needs replacing.
Is this urgent?
It is not usually an emergency, but it gets worse steadily and never better, and the longer it runs the more brick has to be rebuilt along with it. It is one of the repairs we recommend not deferring.