Why Are My Bricks Cracking? Common Causes of Brick Damage

A crack in a brick wall is easy to dismiss as normal wear, but cracking almost always has a specific cause behind it. Understanding what's actually causing bricks to crack helps you figure out whether it's a simple cosmetic fix or something that needs more immediate attention.

Freeze-Thaw Cycles Are the Most Common Culprit

Chicago's winters put more stress on brick than almost any other factor. Water gets into small pores and hairline cracks in brick or mortar, then freezes and expands when temperatures drop, widening the crack a little more each cycle. Over years of repeated freezing and thawing, what started as a barely visible hairline crack can grow into something much more noticeable.

Settling and Foundation Movement

Homes shift slightly over time as the ground beneath them settles, and that movement often shows up first as cracks in brick walls, particularly near corners, windows, and doors. Cracks caused by settling tend to run diagonally and may widen at one end, which is different from the more uniform cracking caused by weather alone. Foundation-related cracking is worth having assessed specifically, since it can point to an issue beyond just the brick itself.

Stair-Step Cracking: A Pattern Worth Knowing

One specific crack pattern worth recognizing is stair-step cracking, where a crack follows the mortar joints in a zigzag pattern rather than running straight through the bricks themselves. This pattern often points to settling or foundation movement, since the crack is following the path of least resistance through the mortar rather than breaking straight through solid brick. Stair-step cracks are common around windows, doors, and corners, and while they don't automatically mean a major structural problem, they're worth having assessed rather than assumed to be purely cosmetic.

Deteriorated Mortar Puts Extra Stress on Brick

Brick and mortar are meant to work together, with mortar absorbing some of the natural movement and stress a wall experiences. When mortar deteriorates and loses that flexibility, the bricks themselves start absorbing stress they weren't designed to handle, which can lead to cracking that wouldn't have happened with sound mortar in place. This is one of the more common ways a mortar problem turns into a brick problem if it's left unaddressed.

Poor Original Construction or Material Quality

Not all cracking comes down to age or weather. Bricks or mortar that weren't properly matched to begin with, corners that weren't reinforced adequately, or construction shortcuts taken during the original build can all lead to cracking well before a wall would normally show wear. This is more common in additions or repairs done without the right materials or technique.

Tree Roots and Nearby Landscaping

Large trees planted close to a home can affect the soil around the foundation as their roots grow and draw moisture from the ground. That shifting soil can contribute to the same kind of settling-related cracking mentioned earlier, even in a home that's otherwise in good condition. If cracking seems to be concentrated on one side of a home near mature landscaping, root activity is worth considering as a possible factor.

When Cracking Is Cosmetic vs. When It's Serious

Not every crack signals a serious problem. Thin, hairline cracks that don't widen over time and don't run through multiple bricks are often more cosmetic than structural. Cracks that are wider than a quarter inch, run diagonally, continue to grow, or appear alongside doors and windows that have started sticking are worth a professional assessment, since those patterns are more consistent with movement or structural stress rather than simple weathering.

Fixing the Cause, Not Just the Crack

Filling a crack without addressing what caused it usually means the same crack, or a new one nearby, shows up again within a few years. If the underlying cause is deteriorated mortar, tuckpointing the surrounding area restores the support brick is supposed to have. If the cause is settling or a construction issue, the repair approach needs to account for that instead of just patching the visible symptom. Identifying the actual cause first is what makes a repair last.

What to Do If You Notice a Brick Crack

Documenting when a crack first appears and taking photos over time can help determine whether it's actively getting worse or has stayed the same. A crack that hasn't changed in width or length over several months is generally lower priority than one that's visibly grown. Either way, having a professional take a look sooner rather than later means you're making a decision based on an actual assessment instead of guessing whether a crack is something to worry about.

Get Your Brick Cracking Assessed in Brookfield, Chicago, and the Chicagoland Area

Kerry Tuckpointing has repaired brick and masonry throughout Ashburn, Brookfield, Oak Lawn, La Grange, and the rest of the South suburbs since 1991. If you've noticed cracking in your brick, our licensed masons can assess what's actually causing it and recommend the right fix. Contact us today for a free estimate.