A rusted lintel cracking brick is a masonry failure you can see on older Chicago buildings, and it rarely announces itself as a lintel problem. What you notice is a brown stain running down the wall under a window, or a crack climbing from a window corner. This article is about reading those signs, what usually sits behind them, and what the repair involves.
What is a lintel, and what failed?
A lintel is the beam that carries the brick above a window, door or garage opening. On many older Chicago brick buildings, it is a steel angle or beam tucked into the wall. You cannot see it from outside. It sits behind or under the brick, and when it is working, you never think about it.
When it is not working, the wall tells you. Technical guidance from the Brick Industry Association connects steel lintel cracking above openings to excessive deflection, and says unprotected steel needs maintenance (Brick Industry Association). We will not tell you what is going on inside your wall from a photo. What we can tell you is what owners see, and what each sign usually asks of a mason.
Why do steel lintels rust in the first place?
Steel does not rust where it stays dry and protected. The same guidance says continuous flashing should go over the angle, even where galvanized or stainless steel is used, with weepholes at the lintel level, and that for harsh climates galvanized steel should be considered. Otherwise, lintels need periodic maintenance to avoid corrosion (Brick Industry Association). Flashing is the layer that collects water that got behind the outer brick and sends it back out (Brick Industry Association).
Chicago gives that system a hard test: rain, snow, and long stretches of freezing and thawing. If a lintel was never flashed, or the flashing has aged out, water can sit on the steel for years. We say "can" on purpose, because we have not opened your wall. The usual picture is simple: water gets in, nothing sends it back out, and the steel stays wet.
On Chicago brick two-flats, three-flats and storefronts, we often find lintels over front windows and garage doors that were never flashed, or were painted once and left alone. Walls with many openings tend to have several lintels aging at the same rate, so one failure is a good reason to look at the others.
What are the warning signs?
You will rarely see the lintel. You see what it does to the brick around it:
- Rust stains running down the face of the brick below a window, door or garage opening.
- Cracks above the corners of the opening, often running up and out at an angle.
- Brick that steps or sags over the opening, or a row that has dropped below the row beside it.
- Mortar joints that open along the underside of the brick above the opening.
- Loose, shifted or missing brick above the opening.
- A window or door that binds, sticks, or has cracked glass.
- Rust flakes or bulging where steel is exposed at the edge of the opening.
One sign alone does not prove the lintel has failed. A rust stain could come from the steel, but it is not a diagnosis, and a crack above a window can have other causes. Several signs at the same opening, especially a stain plus a crack plus a row of brick that has dropped, is the pattern that tells a mason to open the wall and look. See stair step cracks in brick for how crack patterns differ.
How is a failing lintel fixed?
The fix depends on what a mason finds when the brick is opened. Often it means taking out the brick over the opening, removing the failed steel, setting a new lintel with flashing and weepholes, and rebuilding the brick above it. The full process, including how a mason supports the wall while the lintel comes out, is in lintel replacement in Chicago.
The City's permit rules turn on the span of the opening:
| Lintel span | What the City says |
|---|---|
| Up to 6 feet | Eligible for the Express Permit masonry category (City of Chicago) |
| Over 6 feet, up to 25 feet | Needs drawings by an Illinois-licensed architect or structural engineer (City of Chicago) |
| Over 25 feet | Not eligible for Express (City of Chicago) |
The permit requires a licensed mason contractor, unless an owner qualifies to act as their own contractor (City of Chicago). Plan requirements are set by the Department of Buildings, so confirm the current rules before you hire (City of Chicago).
A mason may find the steel in better shape than the stains suggested. In that case, the repair can be smaller: repointing, flashing, or sealing the water source. That is why the first step is an inspection, not a quote for a full replacement.
The span of the opening, how much brick has to come out and be rebuilt, whether the wall needs temporary support, whether drawings are required, and how many openings on the wall are affected. We do not quote numbers on a blog. A mason can give you a real figure after looking at the wall.
What happens if you wait?
Rust stains and cracks do not stay cosmetic. If the lintel keeps failing, brick above the opening can shift, loosen or fall. Chicago's code requires the exterior of a structure to be maintained in good repair and structurally sound, and lists veneer and facings that are not properly anchored as unsafe conditions (City of Chicago). In one public case, a CBS Chicago report on a West Englewood church facade collapse said City records cited failure to maintain exterior walls and a lintel in good repair, and the owner was being prosecuted in Cook County court (CBS Chicago). A small repair today is a lot easier than that.
If bricks are moving or loose over a sidewalk, gangway or entrance, keep people away from the area and call a licensed mason right away. To report a building safety problem to the City, 311 is the intake (City of Chicago).
What should you ask before you hire?
- Are you a City-licensed mason contractor, and who pulls the permit?
- Will you open the wall to look at the lintel before giving me a quote?
- If the lintel needs replacing, how long is the span, and does it need drawings?
- Will the new lintel have flashing and weepholes?
- How will the wall above be supported while the old one comes out?
- Should I have the other openings on this wall checked?
If it is the brick itself that is falling, start with bricks falling off a building. For the larger picture, see our Chicago brick and masonry repair guide. To have a mason look at the stain you are staring at, see our masonry service.
Common questions
No. A rust stain is a sign to look, not a diagnosis. Several signs at one opening, such as a stain, a crack above the corner and brick that has dropped, point more strongly to a lintel problem. A mason can open a small area and check.
Sometimes the steel is in better shape than the stains suggest, and the fix is flashing, repointing or stopping the water. Whether a lintel can stay is a call a mason makes after opening the wall. Do not guess from the ground.
Yes. Replacing a lintel up to 6 feet is eligible for the Express Permit masonry category. Over 6 feet, up to 25 feet, needs drawings from an Illinois-licensed architect or structural engineer. A licensed mason contractor pulls it. Confirm current rules with the Department of Buildings.
It can be. Cracks, dropped courses or loose brick above an opening can mean the lintel is no longer carrying its load. If brick is loose over a walkway or entrance, keep people clear and have a licensed mason look at it promptly.
Sources
- Brick Industry Association: Technical Note 31B: Structural Steel Lintels (PDF)
- Brick Industry Association: Technical Note 7: Water Penetration Resistance, Design and Detailing (PDF)
- City of Chicago: Code Modernization Ordinance, including Title 14X Minimum Requirements for Existing Buildings (PDF)
- CBS News Chicago: South Side church collapse coverage
- City of Chicago, Department of Buildings: Department of Buildings home page
- City of Chicago: Express Permit Program: Masonry Work
- City of Chicago, Department of Buildings: Mason Contractor License
- City of Chicago: Guide to Building Permits: When Is a Licensed Architect or Engineer Required?
Facts last checked: October 7, 2026.
This article explains general rules and common situations in Chicago. It is not legal advice, and City rules change. For a specific property, check with the Chicago Department of Buildings or a licensed professional.