The Short Answer
Sometimes, and appearance alone is not conclusive.
Stair-step cracking through brick mortar joints can accompany foundation movement. It can also result from thermal expansion, missing or inadequate masonry expansion joints, deflection in a steel lintel over an opening, or original construction detailing. The crack pattern itself does not distinguish among those causes.
What does distinguish them is the combination of crack behaviour over time and the floor elevation profile behind the wall. That is why the useful next step is a foundation evaluation rather than a judgement made from a photograph.
Why Brick Cracks in a Stair-Step Pattern
Brick veneer is a facing, not a structural wall. It is tied back to the frame behind it and it sits on the foundation’s brick ledge. Brick units themselves are strong. The mortar joints between them are weaker, and they are the path of least resistance when the wall is stressed.
Stress the wall in any direction and the crack propagates through the joints, running horizontally along a bed joint and then vertically up a head joint, producing the characteristic diagonal staircase. Because the pattern comes from the material properties rather than the cause, it appears regardless of what produced the stress.
Cracks concentrate at openings because windows and doors interrupt the wall and create stress concentrations at their corners. A stair-step crack starting at a window corner is therefore the most common presentation, and it says more about where the wall is weakest than about what moved.
What an Assessment Actually Considers
Width and taper. Not just how wide the crack is, but whether it is consistently wide along its length or tapers. A crack that is wide at the top and narrow at the bottom suggests rotation, which points toward differential movement.
Displacement. Whether the brick on one side of the crack sits proud of the brick on the other. In-plane displacement is a more significant observation than width on its own, because it means the two sections have moved relative to each other rather than simply separated.
Location and pattern across the elevation. One crack at one window is a local observation. Cracking at several openings on the same elevation, increasing toward one end, describes a shape, and shape is what points toward differential settlement.
Change over time. The most informative measurement available to a homeowner, and the cheapest. Mark and date the ends, photograph with scale, repeat after a season.
The floor profile behind the wall. Elevation readings taken inside tell you whether the ground behind that elevation has actually moved. A crack above a flat floor is a masonry question. The same crack above a measured deflection is a foundation question.
Site factors. Downspout discharge, grading, irrigation, and tree proximity along that particular elevation.
What appearance cannot establish
A photograph cannot tell you whether a crack is active or dormant, whether the wall behind it has moved, or what caused it. Two visually identical cracks can sit over entirely different conditions. We will not diagnose a property from an image, and a contractor who offers to is telling you something about their process rather than about your house.
Cracks That Are Usually Not About the Foundation
Fine cracking confined to mortar joints with no displacement, spread evenly across a long wall, often relates to thermal movement or mortar shrinkage rather than support.
Vertical cracking at a long straight run with no openings nearby can indicate missing masonry expansion joints, particularly on newer construction with long unbroken elevations.
Cracking directly above a window or door in a horizontal line may relate to lintel deflection, which is a component question rather than a foundation one.
Cracking at the junction of an addition and the original structure is extremely common and reflects two structures on separate foundations moving independently.
None of these rule out a foundation issue. They simply mean the crack is not on its own evidence of one.
What to Do Next
If the crack is hairline, has no displacement, and you have no other observations, document it: mark the ends, date the mark, photograph with a scale, and check again after a wet season and a dry one.
If the crack has visibly widened, shows displacement, appears alongside sticking doors or uneven floors, or is one of several across the same elevation, request an evaluation. Elevation measurement will establish whether there is movement behind it.
Either way, hold off on cosmetic repair until you know which situation you are in. Filling a crack that is still moving removes the evidence you need and the filler cracks anyway. Our crack repair page explains the difference between cosmetic work, sealing, and structural repair, and when each is appropriate. Our guide on what interior wall cracks can and can’t tell you applies the same reasoning to cracking you find inside.