Dayton Tuckpointing Step cracks above windows and at corners: lintel, settlement, or mortar, and what each costs in Dayton
A stair-step crack in brick, one that follows the mortar joints up and across in stairs, has three possible causes, and in Dayton the address of the crack usually tells you which. Rising from the top corner of a window on a house built after 1950, it is a rusted steel lintel, fixed by lintel replacement at $400 to $1,500 per opening. Climbing a corner from low on the wall, it is settlement, and the brick is repointed at $8 to $20 per square foot only after the movement is understood. Following a weather pattern with no starting point, it is plain mortar failure. Send a straight-on photo of the whole opening and a close-up of the crack with a coin for scale, and you get the diagnosis before the number.
Check this first
- Find the bottom of the crack. Put a finger on the lowest point where the joints are open. If it is the top corner of a window or door, think lintel. If it is a lower corner of a window or down at the foundation, think settlement.
- Look at the lintel. On any window with a step crack above it, look at the steel angle sitting on the brick over the opening. Rust staining on the brick below it, a visible downward bow, or a gap opened under the first course above it means the steel is swelling.
- Count the openings. One cracked window on a sunny wall is a lintel. Three cracks on the same side of the house, all leaning toward the same corner, are a footing moving on wet clay.
- Check the inside. Diagonal plaster or drywall cracks on the same wall, doors that stick in spring and free up in August, or a basement wall with a crack in the same corner all point to settlement, not steel.
- Measure it. Pencil a line across the crack, date it, and look again in three months. A crack that opens in April and closes in August is riding the Miamian clay’s spring water table; one that opens and never closes is still going.
What is usually wrong
| Where the crack starts | Likely cause | Fix and cost |
|---|---|---|
| Top corner of a window or door, post-1950 house | Rusted steel lintel expanding | Lintel replacement $400 to $1,500 per opening, includes repointing the crack |
| Top corner of a window, pre-1930 house with a stone lintel or brick arch | Cracked stone lintel or a dropped arch | Stone repair or replacement on the stone page, $300 to $1,200 |
| Low on the wall, running to a corner, more than one opening | Footing settlement on wet clay | Drainage first, then repoint at $8 to $20 per sq ft once it stops moving |
| Up a corner from the foundation, basement crack in the same corner | Foundation movement | Assessment, foundation repointing $10 to $25 per sq ft where joints have opened |
| No clear start, worst on the weather side | Ordinary mortar failure | Tuckpointing $8 to $20 per sq ft |
| Along the top of a garage door or picture window, brick sagging | Undersized or badly bearing lintel over a wide span | Lintel replacement, top of the $400 to $1,500 range |
Every figure is the pricing page figure. The tuckpointing cost estimator prices the repointing part; the lintel is per opening.
Why Dayton brick step-cracks
Steel and water. The brick on the postwar ranches and two-stories of Kettering, Huber Heights, Beavercreek, and Centerville is a veneer, and every opening carries its brick on a steel angle. Those lintels went in bare, unflashed, and without weeps. Water gets behind brick veneer, runs down the cavity, and sits on the steel. Dayton gives it 41.33 inches of normal annual precipitation and roughly 110 freeze-thaw cycles a year to work on it. Rust occupies several times the volume of the steel it consumes, so the lintel grows, and the brick above it has nowhere to go but up and out along the joints. That staircase is the most common masonry call in the suburbs.
Clay and water. Under most of Montgomery County is the Miamian soil, whose subsoil runs 35 to 45 percent clay and whose perched water table sits 2.5 to 3.5 feet below grade from January through May, which is footing depth. Clay that wet in April and dry in August swells and shrinks, and a footing riding it moves a little every year. The wall shows the movement at its weakest lines, which are the corners and the openings, and the crack steps along the joints because the joints are softer than the brick. On a house built before 1930, whose walls are solid brick on a rubble foundation rather than veneer over a frame, settlement is the more common cause of a step crack, and the lintel over the window is stone or a brick arch that cracks at its ends when the wall beneath it drops.
When it is structural, not cosmetic
A lintel crack is a contained problem: fix the lintel and it is over. Settlement is structural by definition, but most of it in Dayton is slow seasonal movement that stabilizes once the water at the foundation is managed with downspout extensions, regrading, and a working gutter. The signs that push a step crack from watch to act are a crack wider than a quarter inch, a crack that has offset (one side of the joint no longer lines up with the other), brick above an opening that has dropped or bowed outward, a door or window that no longer opens, or a crack that grows month over month regardless of season. Any of those gets an assessment before a quote, and if it needs an engineer, a straight mason says so rather than selling a repoint.
The repair, in order
Cause first. On a lintel crack, the brick above the opening comes out, the steel is replaced with a properly bearing, flashed, and weeped section, the brick is relaid in matched mortar, and only then is the crack line cut out and repointed. On a settlement crack, the water is dealt with, the movement is confirmed stopped, and then the joints are repointed to depth in a mortar matched to the wall’s era: Type N on the postwar stock, a lime mix on anything pre-1930. The blog post on step cracks over the window walks through the questions to answer from photos in more detail.
What to expect on the call
Tell us where the crack starts, how many openings have one, what the lintel looks like underneath, and whether anything inside has cracked. Two photos per opening settle most of it. You get a diagnosis, a per-opening or per-foot number from the published table, and, on a settlement crack, an honest “watch it through one spring” if that is the right answer. Lintel work follows the mortar season, mid-April to Dayton’s average first freeze on October 25, but a bowed lintel with loose brick over a doorway gets shored the day it is seen.
Frequently Asked Questions
What causes a stair-step crack over a window in brick?
On a house built after about 1950, a rusting steel lintel almost every time. The steel angle carrying the brick over the opening was usually set without flashing, water sits on it, and rust takes up several times the volume of the steel it replaces, lifting the brick above and opening the joints in a staircase from the window corner. On older houses with stone or brick-arch lintels, the same crack is more often settlement.
How much does it cost to fix a step crack in Dayton?
Lintel replacement runs $400 to $1,500 per opening, which includes removing the brick above, setting a new flashed lintel, relaying, and repointing the crack. A settlement crack that has stopped moving is repointed at $8 to $20 per square foot, usually at the $500 to $800 minimum. A crack that is still moving needs the foundation looked at before anyone touches the brick.
Can the crack just be repointed?
It can, and if the cause is still there it reopens by spring. Repointing is the last step of a step-crack repair, not the first. Ask whoever quotes it what is moving the brick; if the answer is nothing, ask why it cracked.
How do I tell a lintel crack from a foundation crack?
Look at where it starts. A lintel crack begins at the top corner of a window or door and climbs outward, often with rust stains on the brick below the lintel and a bowed steel edge. A settlement crack begins low, near a lower window corner or the foundation, runs diagonally toward a corner of the house, and usually shows up at more than one opening on the same side, sometimes with cracked plaster inside.