Steel Lintel Repair & Replacement

If you've got a crack stepping up from the corner of a window, with rust bleeding down the brick below it, the mortar isn't your problem. The steel lintel behind it is. We replace rusted lintels for homeowners across Lincolnwood, Niles, Morton Grove, and the near-north suburbs of Chicago, mostly on the postwar brick homes that make up the bulk of housing in all three villages.

What a lintel does, and why it's usually the first thing to fail

Every window and door opening in a brick wall needs something to carry the weight of the brick above it, since brick alone can't span an opening. That's the lintel, a steel angle or plate set into the wall right above the frame. It's also one of the few pieces of structural steel embedded directly in masonry, sitting in a spot that holds moisture longer than the brick around it. Left there for 60-plus years, as it has been in most of the postwar homes across Lincolnwood, Niles, and Morton Grove, that steel rusts.

Rust jacking: the mechanism behind the crack

Rust isn't just cosmetic corrosion. Rusted steel occupies more physical volume than the steel it came from, sometimes several times more. As that rust builds up on a lintel embedded tight against brick and mortar, it physically pushes outward, a process masons call rust jacking. That pressure is what cracks the mortar joints above the window in a stair-step or horizontal line, and in worse cases bows the brick itself outward. It's slow, which is exactly why it goes unnoticed until the crack is already significant.

What to look for

Stair-step or horizontal cracking in the mortar directly above a window or door frame, not scattered randomly across the wall.

Rust staining streaking down the brick face below the opening, often the clearest early sign before cracking is visible.

Brick that's visibly bowed or displaced outward above the opening, a sign the rust jacking has been active for a while.

A gap opening up between the top of the window frame and the brick above it, as the lintel itself deforms.

The repair

We remove the brick immediately above the affected opening, cut out the rusted lintel, and set a new galvanized or properly primed and coated steel lintel sized to the opening. The brick above it gets rebuilt and the joints repointed to match the surrounding wall, the same color and joint matching we use on any tuckpointing job. Done right, the repair is close to invisible once the mortar cures.

What it costs

A single-window lintel replacement typically runs $1,500 to $2,500. Homes with multiple affected openings, common once one lintel has failed since they're usually the same age and spec, run $2,500 to $5,000 or more depending on count and access. Where we're quoting by length rather than by opening, figure roughly $200 to $600 per linear foot. Access is the biggest cost driver: a first-floor window is straightforward, a second-story opening needs staging.

Don't just patch the mortar

This is the single most common shortcut we see, and it doesn't work. Repointing the cracked mortar over a rusting lintel looks fine for a season, maybe two, while the steel underneath keeps corroding and expanding. The crack comes back, usually wider, because the actual cause was never addressed. If you've had a window crack repointed before and it's cracking again in the same spot, that's the lintel talking.

Related work

If your home has scattered mortar wear beyond just window openings, that's a tuckpointing job, and if the cracking is at the chimney rather than a window, see our chimney repair page. Not sure which one applies? Send us a photo and we'll tell you plainly what we're looking at.

Frequently asked questions

What is a lintel and why does it rust?

The lintel is the steel angle or plate above a window or door opening that carries the weight of the brick above it. It sits embedded in the wall, where it stays damp longer than the surrounding brick, and steel exposed to moisture for decades rusts. Rust takes up more volume than the original steel, a process called rust jacking, and that expansion cracks and pushes out the brick above the opening.

How do I know a lintel is failing?

The giveaway is a stair-step or horizontal crack in the mortar joints directly above a window or door, sometimes with the brick visibly bowing outward, plus rust staining bleeding down the brick face below the opening. Homes from the 1940s through 1960s in Lincolnwood, Niles, and Morton Grove are squarely in the age range where this shows up.

What does lintel replacement cost?

A single-window lintel typically runs $1,500 to $2,500. Multiple openings on the same job run $2,500 to $5,000 or more depending on count and access. Where we price by length rather than by opening, figure roughly $200 to $600 per linear foot.

Can you just tuckpoint over a cracked lintel instead of replacing it?

No, and we won't sell you that. Repointing the mortar over a rusting lintel hides the crack for a season or two while the steel keeps rusting and expanding underneath. The brick above the opening will crack again, usually worse. The mortar only holds once the lintel itself is out and replaced.