Signs your brick, stone or concrete needs repair

Updated November 11, 2026 · KeystoneProGuide editorial team

What should you look for?

The National Park Service (NPS) lists the conditions to watch on exposed masonry: cracking, spalling, bowing, sweeping, leaning and mortar deterioration. Bowing is a vertical bulge in a wall, sweeping a horizontal one. Add water marks and white salt deposits, and on concrete, cracks, crumbling and lifted slabs, and you have most of what a homeowner can see from the ground.

Most of these signs do not mean an emergency. What they mean depends on where they are and whether they are getting worse.

Is the mortar wearing away?

Look closely at the joints. Mortar that is recessed behind the face of the brick, crumbles when scratched, or has fallen out in places is doing what the NPS says it is meant to do: it is the softer, replaceable part of the wall that sacrifices itself so that water and salts pass through it rather than through the bricks. Worn joints are what repointing replaces.

The opposite sign is a warning too. If the joints are sound and hard but the bricks or stones around them are wearing away, the mortar may be harder than the masonry. The NPS shows a sandstone house where hard, portland-rich repointing left the joints standing proud while the stone between them wore back into a honeycomb pattern.

Are bricks flaking or crumbling?

Spalling is the face of a brick or stone peeling off in slices. The NPS explains one cause: water carries salts into the masonry, and as the salts crystallize inside the pores they break the brick apart from within. Another is a lost surface. The NPS says sandblasting and other abrasive cleaning remove the hard outer skin of brick and expose the softer core, which then takes in water and suffers freeze-thaw damage.

What do cracks in brick walls mean?

The pattern tells you something.

• Stair-step cracks along the joints. The NPS shows these as typical of a wall that was probably moving with heat and moisture. Such cracks are normally cyclical, opening wider in cold weather and narrowing in hot.
• Cracks through the bricks themselves. Structure-related cracking, the NPS says, usually runs through the units rather than the weaker mortar, and is usually found over windows and doors.
• Cracks above an opening. In older walls, wood lintels sag or decay and iron or steel lintels deflect or rust, and the masonry above them cracks.
• Cracks or outward movement just below the eaves. The NPS links these to roofs spreading outward because their horizontal ties have failed or are missing.

The NPS advises watching a crack over time if you can, to see whether it is active. Active cracks get a flexible sealant; inactive ones can be repointed.

Is a wall bulging or leaning?

Bowing, sweeping and leaning are the signs to take most seriously, because they show the wall has moved. The NPS warns that when moisture breaks down masonry over time, units or a whole wall can lose the ability to carry its weight, ending in collapse, and that damage hidden behind an impervious coating may not be noticed in time. A bulging wall is a reason to get a structural assessment, not only a mason's quote.

Are there white stains or a tide line?

White, fuzzy deposits that brush off are efflorescence. The NPS describes "rising damp", moisture wicking up a wall from the ground, which often leaves a high-tide line in basements, often 3 to 4 feet above the floor, with salts along it. Efflorescence on its own is a sign of water moving through the wall; the question is where the water comes from.

Is the basement damp or the foundation cracked?

Penn State Extension says stormwater can cause cracks in foundations and damage around windows and doors, and that flooded basements are a common and expensive result of heavy storms. Look outside first: downspouts emptying against the wall, soil sloping toward the house, and open cracks where water can get in. The Federal Emergency Management Agency's first steps are filling foundation cracks with mortar and masonry caulk and grading soil away from the house.

What does a failing sidewalk, step or driveway look like?

Penn State Extension says chloride from deicing salt causes chemical changes and freeze-thaw effects in concrete that lead to cracks, crumbling and discoloration. For a public sidewalk, your township may set its own definition. Lower Merion's code, for example, treats a sidewalk as hazardous when one block sits more than 1/4 inch above the next, when a crack is 1/2 inch or wider, or when the surface is spalling or flaking enough to cause slipping or tripping. In Philadelphia, Parks & Recreation will inspect a street tree whose roots are lifting the paving, but the owner remains responsible for the sidewalk.

What should you do next?

Photograph what you see, note the date, and watch whether it changes. For what you can safely handle yourself, see whether to do it yourself or hire. When the time comes, how to choose a masonry contractor explains the checks, and local businesses are on the masonry contractors page.

Sources

1. Common Problems with Brick Masonry, U.S. National Park Service
2. Mortar, Unsung Hero of History, U.S. National Park Service
3. This Masonry is for the Bees!, U.S. National Park Service
4. Road Salt Pollution - Moving from Monitoring to Action, Penn State Extension
5. Is Stormwater Damaging My Property?, Penn State Extension
6. Fact Sheet: Be Flood Smart. Protect Your Property, Federal Emergency Management Agency
7. Streets and Sidewalks, Article IV: Defective Sidewalks and Curbs, Lower Merion Township
8. Street tree frequently asked questions, City of Philadelphia, Parks & Recreation