A stair-step crack in a brick wall has a reputation. Search for one and you’ll find plenty of pages that call it a settlement crack and stop there. Sometimes that’s right. But masonry references describe the same stepped shape coming from several different causes, and the same is true of horizontal and vertical cracks. The shape narrows the list. It rarely picks the answer.
This post is a pattern guide for the masonry and stucco walls around a La Jolla home: brick or stone veneer, concrete block garden and retaining walls, chimneys, and stucco over wood framing. Our wall cracks page covers how finish and structural concerns get sorted and who evaluates what. Our earlier post on structural vs cosmetic wall cracks goes room by room through drywall and plaster. Here the focus is shape: what each pattern is associated with in published references, and which details push it toward a structural question.
Read a crack by its shape, where it starts and ends, whether it tapers, and whether it’s changing. No single shape proves a cause.
Why masonry cracks in patterns at all
Brick and block walls are units set in mortar, and cracks in them often follow the joints: up and over through the head joints and bed joints in a stair-step, or straight along one bed joint as a horizontal line. A crack that cuts through the bricks or blocks themselves is worth noting separately when you photograph it.
The Brick Industry Association’s Technical Note 18 says: “The shape, location and magnitude of cracking will often indicate the cause.” It also says cracking “is perhaps the most frequent type of distress that affects masonry walls.” That’s a reason to read the pattern carefully rather than assume the worst.
Stair-step cracks
A stair-step crack runs diagonally through a masonry wall by following mortar joints, stepping up one course at a time.
Foundation movement is one cause. TN 18 says unstable or expansive soils “often cause movement or differential settlement in foundations that support brick masonry,” and that foundation settlement “may cause diagonal/stepped cracking in the brickwork and mortar joints directly above the foundation.” It also describes cracking where one part of a structure settles more than the part next to it.
Expansion is another. Brick grows slowly over its life, and TN 18 notes that in walls with openings, “diagonal cracks may occur in brickwork between windows or doors,” usually extending from the head or sill at the jamb of the opening. That diagonal can look a lot like a settlement crack.
Earthquakes are a third. FEMA 306, an engineering manual for evaluating earthquake-damaged concrete and masonry wall buildings, describes bed-joint sliding as “commonly observed both in the field and in experimental tests,” in two forms: “sliding on a horizontal plane, and a stair-stepped diagonal crack where the head joints open and close to allow for movement on the bed joint.” That manual was written for engineers assessing masonry buildings, not wood-frame houses with veneer, but it’s a useful reminder that shaking produces stepped cracks too.
Clues that help sort them:
- Taper. TN 18 says “deflection and settlement cracks are identified by a tapering shape.” A crack that’s wide at one end and closes to nothing at the other suggests rotation or one side dropping. Note which end is wide.
- Where it starts. Cracks rising from the corners of windows and doors point to stress at the opening. Cracks rising from low on the wall near the foundation point to what’s happening below.
- Offset. If one side of the crack sits proud of the other, or the courses no longer line up, the wall has moved, not just cracked.
- Timing. A stepped crack that appeared right after a felt earthquake is a different conversation from one that’s grown slowly over several winters. Our companion post on seasonal vs progressive cracks covers how to read change over time.
Horizontal cracks
A horizontal crack runs along a bed joint, or across a stucco wall, roughly level. Its meaning depends heavily on what the wall is doing.
In a wall that holds back soil
A horizontal crack in a block or concrete wall with soil against one side is a lateral-load question. The California Residential Code requires foundation walls to be designed “in accordance with accepted engineering practice” when they’re subject to hydrostatic pressure from groundwater, or support more than 48 inches of unbalanced backfill without permanent lateral support at the top or bottom. Retaining walls that aren’t supported at the top and hold back more than 48 inches of fill must be designed against overturning and sliding. The code treats soil pressure on a wall as an engineering problem. A horizontal crack in that kind of wall deserves the same treatment.
If the wall also leans or bows, read our posts on leaning retaining wall causes and the retaining wall monitoring checklist, and see the retaining wall repair page. Horizontal cracks in the stem walls and foundation walls under the house belong on our foundation cracks page.
In freestanding masonry and veneer
Without soil pushing on it, a horizontal crack has other likely sources:
- The brick-to-concrete line. TN 18 explains that “brick walls expand and concrete foundations shrink,” and when the two are bonded together the difference creates shear stress at the joint. That can crack the top of the foundation or move brickwork away from a foundation corner. New construction handles it with a bond break or flashing at that line.
- Earthquake shaking. FEMA 306 describes sliding “on a horizontal plane” along bed joints, and for out-of-plane bending it describes a mode involving three cracks across the wall: one at the top, one at the bottom, and one at midheight.
- Rusting steel. TN 18 notes that corrosion of steel inside or attached to masonry increases its volume enough to crack or spall the masonry. Brick veneer on a house is held to the framing with metal ties, and the California Residential Code requires those ties to be corrosion-resistant. On a house this close to the ocean, where the Weather Service describes moist conditions as “commonplace,” it’s a reasonable thing to ask an evaluator to look at if veneer is cracking or bulging.
In stucco
Exterior plaster is a rigid skin over a framed wall. The California Residential Code calls for a weep screed “at or below the foundation plate line” on exterior stud walls, set at least 4 inches above earth or 2 inches above paving, so water that gets behind the stucco can drain out. A horizontal crack running just above that line marks where the stucco meets the base of the wall. That’s a location to note, not a diagnosis. It matters more if the stucco below the crack is bulging, stained, or soft, which points to water, or if the crack lines up with a crack in the foundation below, which points to movement.
Horizontal cracks at the floor line of a two-story stucco wall are another familiar location. TN 18 notes that wood’s shrinkage along the grain is usually small enough to neglect, so most of it happens across the grain. At a floor line, the floor framing and plates are stacked with their cross-grain dimension running up and down the wall, which makes framing shrinkage one plausible source. A crack that pairs with a sloping upper floor or binding upstairs doors deserves a closer look.
Vertical cracks
Vertical cracks get less attention than the other two, but brick walls produce some characteristic ones.
At corners. TN 18 explains that brickwork expands toward a corner from both sides. Without an expansion joint nearby, it can crack at the corner, typically “at the first head joint on one side of the corner.” FEMA 306 separately describes a vertical crack at the corner of a masonry wall from out-of-plane bending during shaking.
At offsets. Where two wall planes meet at an inside corner, TN 18 describes expansion that rotates the offset and opens vertical cracks.
In block walls. Concrete block has a net shrinkage over time, according to TN 18. A long garden or property wall built without enough joints can crack vertically as it shortens.
A vertical crack that is the same width top to bottom and isn’t offset leans toward material movement. One that tapers, or where the two sides no longer line up, is more likely telling you something moved under or behind the wall.
Chimneys
Chimneys are masonry too, and they show every pattern above. Our room-by-room wall cracks post flags the main warning sign: a chimney separating from the house wall with a gap that widens toward the top. If you see that, have it looked at rather than caulked. Our seismic retrofit page covers how older masonry fits into earthquake planning.
Repoint, seal, or wait?
Repointing mortar or patching stucco over a crack that has stopped moving is ordinary maintenance. Sealing a crack that is still moving hides the evidence an evaluator would use, and a crack that is still moving can open again through the patch. If you’re not sure whether a crack is still active, photograph it with a ruler in frame and a date, then compare after a wet season and a dry season. Our structural vs cosmetic wall cracks post explains which “cosmetic” stucco and drywall work still needs a City permit.
When to get an evaluation
Ask for a professional look when:
- A crack is offset, bulging, or wider at one end and getting wider
- A wall that retains soil has a horizontal crack, a lean, or a bow
- Stepped or diagonal cracks show up on several walls on one side of the house
- Veneer is pulling away from the framing, or a chimney is separating from the house
- Cracks pair with sticking doors, sloping floors, or new cracks inside
- The crack appeared or changed after a felt earthquake, a storm, or nearby grading
A structural inspection looks at walls, framing, and load path along with the foundation. When a pattern points to soil pressure, settlement, or seismic damage, we coordinate with licensed engineers as needed.
Cost factors, not prices
We don’t publish repair prices. Scope depends on what the crack turns out to mean and on factors such as the wall type, its height and whether it retains soil, access, whether drainage or a leak needs correcting first, whether veneer ties or framing need to be opened up and checked, and whether engineering or permits are involved.
Next step
If you have a stair-step, horizontal, or vertical crack you can’t read, we evaluate homes anywhere in La Jolla and can help you sort finish repair from structural questions. Request a Free Quote, or call (650) 739-6537.
Sources (accessed October 12, 2026)
- Brick Industry Association, Technical Note 18, Volume Changes – Analysis and Effects of Movement (May 2019)
- FEMA 306 / Applied Technology Council ATC-43, Evaluation of Earthquake Damaged Concrete and Masonry Wall Buildings: Basic Procedures Manual (1998), Chapter 7, §7.2.5, §7.2.10, §7.2.16
- 2025 California Residential Code, Sections R404.1.1 and R404.4 (foundation and retaining walls)
- 2025 California Residential Code, Sections R703.7, R703.7.2.1, R703.8, and R703.8.4 (exterior plaster and masonry veneer)
- NOAA / National Weather Service, Technical Memorandum NWS WR-270, Climate of San Diego, California (revised September 2004)