A spalled brick is one that has lost its face. The hard outer surface flakes away or pops off in a chunk, and what's left is the rough, softer interior of the brick. A few spalled bricks on a hundred-year-old wall are normal wear. A wall where they keep multiplying has a specific problem, and replacing the bricks without finding it just means replacing them again.
The good part is that spalling tends to leave clues. Where it happens and what it looks like usually point to the cause.
Why the face comes off
Brick is fired clay. The firing gives it a denser, harder outer layer, sometimes called the fire skin, over a more porous body. As long as that outer layer is intact, the brick sheds most of the weather that hits it. Spalling happens when something inside or just behind the face pushes outward with more force than the face can take.
In practice, that force almost always comes from one of a handful of sources, and water is involved in nearly all of them.
The common causes
Water and freezing
When brick is saturated and freezes, the ice expands and pushes on the pores near the surface. Over many winters, the face lets go. This is the most common cause of spalling in New York, and it's concentrated wherever brick stays wet: parapets, chimneys, sills, the top courses under the roof, areas under leaking gutters, and the bottom few courses near the sidewalk. Our post on freeze-thaw damage covers it in depth.
Mortar that's harder than the brick
A wall is designed so the mortar is the weaker, more flexible part. It absorbs movement and lets moisture escape through the joints. When old, soft brick is repointed with a hard, cement-rich mortar, that relationship flips. Movement and moisture get forced through the brick instead, and the edges and faces of the brick break off next to the joints. If spalling started or got worse a few years after a repointing job, suspect the mortar. Our repointing guide explains how the mortar should be chosen.
Sealers, paint and coatings
A coating on the face of the brick doesn't stop water from getting into the wall through joints, cracks and the top of the wall. What it does stop is that water drying back out through the face. The brick stays wetter, and freezing and salts do their damage just behind the coating. A painted or sealed wall that's peeling in patches, with brick coming off along with the coating, is showing this.
Salts
Water moving through masonry carries dissolved salts. When they crystallize just under the surface instead of on it, the crystals grow in the pores and push the face off in flakes or powder. It's especially common near the ground, where de-icing salt and groundwater feed it, and it often shows up alongside white deposits on the brick. See our post on efflorescence for more.
Rusting steel
Steel embedded in or behind the brick, including lintels over windows, shelf angles at floor lines, old anchors and even abandoned hardware, expands as it rusts. That growth pushes the brick in front of it outward, cracking it and popping off faces. This kind of spalling lines up with the steel: along the tops of window openings, in horizontal bands at each floor, or in small clusters around an embedded bolt. Replacing the brick without dealing with the steel buys you a year or two.
Walls with no room to move
Brick expands slightly over its life and with every change in temperature. On newer buildings with brick veneer on a concrete frame, the brick needs expansion joints and soft joints under the steel shelf angles to accommodate that movement. Where they're missing, the brick gets squeezed, and the edges and corners crush and spall, often at building corners or in horizontal lines at each floor. We cover this under horizontal cracks in our guide to cracks in brick.
Poor brick, or damaged brick
Some brick was never durable. Older New York buildings sometimes have soft, underfired brick, often called salmon brick for its pale orange color, that was meant for the inside of the wall but ended up on the exterior, especially where the wall was patched in the past. These bricks spall one at a time, scattered across an otherwise sound wall.
Brick that has been sandblasted or aggressively pressure washed has had its fired face stripped away, and it deteriorates much faster afterward. If the whole wall looks pitted and rounded after an old cleaning job, that's likely why.
Reading the pattern
Before anyone starts replacing brick, look at where the spalling is. Scattered single bricks across a sound wall usually point to bad individual bricks. Spalling concentrated at the tops of walls, on parapets and chimneys, or under leaks points to water and freezing. Bands at the bottom of the wall point to salts and splash-back. Lines along window heads or floor levels point to steel or missing expansion space. Spalling next to the joints after a repointing job points to the mortar. Widespread spalling behind a peeling coating points to the coating.
More than one cause can be at work on the same building, which is common on older walls that have had several rounds of repairs.
How spalled brick gets fixed
Replace the brick. The standard repair is to cut out the damaged brick and the mortar around it and set a new or salvaged brick in its place. The replacement should match the original in size, color and texture, and just as importantly, it shouldn't be much harder or less absorbent than the brick around it. A very hard modern brick set into a wall of soft old brick can push the problem onto its neighbors. Typical NYC pricing runs about $45 to $85 per brick installed, not counting scaffolding, which on a tall building is often the larger cost. Our repair cost guide has more on how that adds up.
Turn it around. On older solid walls, a brick with a spalled face but a sound back can sometimes be removed and reinstalled back-to-front, so the undamaged face shows. It keeps original material and color on the wall, which matters on landmarked buildings. It only works when the brick comes out intact and the back face is presentable.
Patch shallow spalls. For a few shallow spalls where matching brick is hard to find, a tinted masonry repair mortar can rebuild the face. Done well on a small scale it can look right and last reasonably. It isn't a good answer for large areas or deep damage, and on a landmarked building LPC will want to see how the patch matches before approving it. Our post on LPC approval covers that process.
Fix the cause. This is the part that decides whether the repair lasts. Repoint hard mortar with a compatible softer mix. Replace rusting lintels and shelf angles and add flashing. Cut in expansion or soft joints where the wall has no room to move. Repair coping, flashing, gutters and sealant so the wall stops getting soaked. If a coating is trapping moisture, it may need to come off, which should be tested carefully on a small area first because removal can damage the brick too.
What not to do
Don't seal, paint or stucco over spalling brick. A covering hides the damage for a season, traps water against the damaged brick, and eventually comes off in sheets along with more of the brick. And don't replace brick without asking why it failed, since the new brick will be exposed to exactly the same conditions.
When spalling becomes urgent
Spalled pieces fall. On a low wall over a garden that's a nuisance. Over a sidewalk or a building entrance, it's a hazard, and on a building taller than six stories it's the kind of condition a facade inspector classifies as Unsafe, which means a sidewalk shed and a 90-day repair deadline. Minor spalling usually shows up in a SWARMP report as something to fix before the next cycle. If you're seeing loose pieces or fragments on the sidewalk, have the area checked and made safe right away.
Brick replacement, like other exterior masonry, needs temperatures above about 40°F for the mortar to cure, so in New York it's a spring-to-fall job. If you're seeing spalling now, there's still time to get the worst of it done before winter.
Send us photos of the spalling
NYC Superior Construction replaces spalled brick, repoints, and repairs the lintels, parapets and shelf angles behind it across New York City, Nassau, Westchester and Rockland counties, and Central and North New Jersey. Send us a few photos showing where the spalling is on the building and a close-up of the damaged brick, and we'll tell you what we think is causing it. See our masonry restoration page for more on the work we do.
Frequently asked questions
What is spalling brick?
Brick whose hard outer face has flaked, peeled or popped off, exposing the softer interior. It's almost always driven by water, through freezing, trapped moisture, salts, hard mortar or rusting steel.
Is spalling brick dangerous?
Pieces can fall, which is a hazard over sidewalks and entrances. Spalled brick also absorbs more water and deteriorates faster.
Can spalled brick be repaired without replacing it?
Sometimes. Shallow spalls on a few bricks can be patched with tinted repair mortar, and sound old brick can sometimes be turned around. Deep or widespread spalling usually means replacement.
Will sealing brick stop spalling?
Usually not, and it can make it worse by trapping moisture and salts behind the surface.
This article is general information about masonry repair, not engineering advice. Loose masonry over a public way should be secured promptly. Last reviewed: September 23, 2026.