Are Spalling Bricks Dangerous? What to Watch For

Are spalling bricks dangerous? It depends on where they are and how loose they are. A flaked patch at knee height is a warning that water is getting into the wall. A face that is lifting four stories up, over a sidewalk, is a hazard now. The skill is telling which one you have before the wall decides for you.

What does spalling actually mean?

Spalling is the face of the brick breaking away: flakes, chips, or a slab of the outer surface coming off and leaving a rough, often darker pit behind. It is damage to the brick itself, not just the mortar. For what it looks like, see what does spalling brick look like.

It is a failure with a short list of causes:

• Salt crystallizing inside the brick. Crystals forming under the surface create pressure that can make the outer face spall or delaminate (BIA).
• Freezing of saturated brick. The same source lists freeze-thaw of saturated brick as another cause (BIA). We explain it in how freeze-thaw damages Chicago brick.
• Mortar harder than the brick. When mortar is less permeable than soft brick, moisture and salts move out through the brick face instead, and the face can pop off. The National Park Service shows trapped moisture popping surfaces off bricks behind hard portland cement mortar (NPS). Stress in a wall should be relieved by the mortar, not the brick (NPS).

All three come back to water. If you want the cause, start with where the wall stays wet.

So when are spalling bricks dangerous?

Think about what happens when the damage keeps going and where gravity points.

Low and local: a warning. A few flaked faces near the ground are not going to hurt anyone today. They tell you the wall is taking in water and the brick is giving up. Fixing it now is cheaper than later.

High, loose or widespread: a hazard. Danger rises when:

• the spalled areas are above a sidewalk, walkway, gangway, alley or doorway
• faces are lifting, hollow-sounding or hanging by an edge
• it is on a parapet, chimney, cornice or other projection, where there is nothing behind the brick to hold it
• the spalling is spreading, or a bulge or open crack sits next to it

Falling masonry in Chicago is not theoretical. In July 2016, bricks fell from a two-family home in North Lawndale and injured two passersby, according to a local news report (ABC7 reported). In a separate case, City records cited a West Englewood church for failing to maintain its exterior walls and a lintel, and the owner was being prosecuted (CBS Chicago). Those are about large failures, not a single spalled brick, but they show where unchecked masonry can end up.

What does the City say about it?

The Chicago code says the exterior of a structure must be maintained in good repair and structurally sound. Among the listed unsafe conditions are masonry joints not kept weather resistant or water tight, and veneer, cornices, belt courses, corbels, trim and facings not properly anchored (City of Chicago).

The City's high-rise exterior wall program does not reach a typical two-flat or three-flat. But an inspector can still cite loose masonry, parapet, cornice or lintel conditions after a 311 complaint. Inspections of occupied buildings are largely complaint-driven (City of Chicago). A neighbor who sees bricks on the sidewalk is a complaint.

What are the warning signs it is getting worse?

Check from the sidewalk, with binoculars, after the thaw in spring and again after the first hard freeze in fall.

• Flakes, chips or fragments of brick face on the ground, sills or gutters
• Spalled patches that are larger or more numerous than last year
• Faces that sound hollow or move when pressed (do this only at ground level)
• Spalling next to joints that were recently repointed
• White powder or salt crust nearby, which points to water and salts moving through the wall (BIA)
• Spalling at the top of the wall, around a chimney, or under a parapet coping
• Rust stains, a bulge, or a stair-step crack in the same area
• A wall that stays dark and damp after the rest has dried

Several of those at once, or any of them above a walkway, is a reason to have it looked at now. Do not stand under it to inspect it.

How is spalled brick fixed?

The fix depends on how deep the damage goes and why it happened.

1. Find and fix the water. Gutters, downspouts, copings, flashing and open joints first. If you skip this, the repair fails again.
2. Take off anything loose. A mason removes unsound faces before they come down on their own.
3. Repair or replace. Some shallow spalling can be dealt with without replacing a brick, depending on the case (see can you fix spalling brick without replacing it). Badly spalled bricks are cut out and replaced with matching brick, which is work covered in replacing spalled bricks.
4. Repoint with the right mortar. The new mortar must be softer and more vapor-permeable than the brick and no harder than the original (NPS). Tuckpointing done wrong can start the spalling over.

Masonry repair is permit work in Chicago. The City lists tuckpointing and masonry wall repair in its Express Permit masonry category, and masonry permits go through a licensed mason contractor. Confirm details for your building with the Department of Buildings.

If something is coming down now, emergency work that normally needs a permit may be done first to prevent imminent harm. The permit application is due the next business day, and the work cannot be concealed without an inspector's approval (City of Chicago). Protect the walkway first and call a mason.

If you are looking at spalling and cannot tell whether it is a warning or a hazard, our masonry team will look at it and tell you which. For the bigger picture, our Chicago brick and masonry repair guide covers the whole wall, and bricks falling from a Chicago building explains what fails when it goes wrong.

Common questions

This article explains general rules and common situations in Chicago. It is not legal advice, and City rules change. For a specific property, check with the Chicago Department of Buildings or a licensed professional.