Chicago brick two-flat problems almost always start where water gets in: mortar joints, the face of the brick, the tops of the walls, the lintels over openings and the back porch. A brick wall can look solid from the sidewalk while one of those spots has been quietly failing for years. The signs are visible if you know where to stand and what to look at.
This is a breakdown of how a brick two-flat fails, what the warning signs look like, and how the repair is done. For the basics of the building itself, start with what a Chicago two-flat is and what it needs, and for the full picture of building types see our Chicago building types guide.
What actually fails on a brick two-flat?
The wall is a system. Brick is the face, mortar is the joint between each brick, and steel or stone lintels carry the load over windows and doors. When one part gives, the others take the strain.
The City's rule for existing buildings names the same parts. Title 14X says the exterior of a structure must be maintained in good repair, structurally sound and sanitary, and it lists as unsafe masonry joints that are not weather resistant or water tight, veneer, cornices, belt courses, corbels, trim and facings that are not properly anchored, and exterior stairs, porches and balconies that are not structurally sound (City of Chicago).
Here is how the failure usually runs:
- Mortar opens. Joints crack, crumble or wash out, and water gets into the wall.
- The brick takes the water. Salt crystallizing inside the brick can make the outer surface spall or flake off, and so can freezing while the brick is saturated (NPS Preservation Brief 2).
- Steel and anchors rust. Lintels over openings need periodic maintenance in a harsh climate, and unprotected steel is the weak link (Brick Industry Association).
- Something moves. A brick, a coping stone, a piece of cornice or a porch rail comes loose.
Step four is the one that gets noticed. Steps one through three are where the money and the time were.
What are the warning signs a brick two-flat is failing?
Walk the building on a dry day: front, both sides through the gangway, rear, then look up at the roofline. Check for:
- Mortar you can scrape out with a key, or joints that are sandy, recessed or missing.
- Brick faces flaking, peeling or sitting in a pile at the base of the wall. Flaking brick is spalling, not just cosmetic.
- White, powdery staining on the wall. That is efflorescence, a sign that water is moving through the masonry.
- Cracks over windows and doors, or a window or door frame that no longer sits square.
- Cracks that run through the mortar and brick in a stair-step line, or a section of wall that bulges or leans.
- Loose or missing coping, cornice pieces or parapet brick at the top of the wall.
- Gaps where the brick meets the porch, the stairs or the neighboring building.
- A porch or stair that moves, bounces or has loose guards. The City treats exterior stairways, porches and balconies as something that must stay structurally sound, properly anchored and able to carry the load (Title 14X).
- Water stains on interior walls and ceilings below the roofline or at the front and rear walls.
Efflorescence on its own is not an emergency. Falling brick, a leaning wall or a moving porch is. If you see that, treat it as urgent and keep people away from the area.
On older brick two-flats, the problems we often find stack. A wall that has needed tuckpointing for a long time also has a cracked lintel over a window, and the parapet at the top has lost its coping. Owners rarely call about the first sign. They call when something falls, a tenant complains or a notice arrives. This is a typical pattern, not any one building.
Why do brick two-flats fail this way?
Water, and what water does when Chicago winters hit it. A wall that takes in water and then freezes pushes the face off a brick. Salt carried by water does similar damage from inside. This is a general masonry principle, not something unique to this city, but a climate with many freezing mornings a year gives it plenty of chances.
Repairs make it worse when the wrong material goes into an old wall. Repointing mortar has to be softer and more vapor permeable than the brick and no harder than the historic mortar. Assuming a harder mortar is a better one is a common mistake, and a mortar stronger than the masonry causes cracking and spalling of the brick that cannot be easily repaired (NPS Preservation Brief 2). When mortar is less permeable than the brick, moisture and salts move out through the brick instead, and the face can pop off (NPS Preservation Brief 2). This is preservation guidance, not a City mandate, but it is why a gray, hard patch on an old wall is a red flag. We go through it in why Chicago common brick is soft.
How is a failing brick two-flat repaired?
It depends on how far the damage has gone. The usual sequence:
- Find where the water is coming from. A roof edge, a failed coping, a leaking downspout or an open joint. Fixing the wall without fixing the source means doing it twice.
- Repoint (tuckpoint) the joints that have failed, with a mortar matched to the old wall. See our Chicago tuckpointing guide.
- Replace the brick that has failed, not just fill over it.
- Repair or replace lintels that have rusted or cracked.
- Rebuild the parapet or top of the wall if the coping and the brick below have failed.
- Repair the porch separately, with the City's rules in mind.
On the permit side, the City's Express Permit program lists tuckpointing and routine masonry repair as eligible work, and also covers replacing a lintel up to 6 feet and rebuilding a masonry parapet wall up to 2,500 square feet. It does not cover rebuilding all layers of an exterior wall or a parapet taller than 48 inches (masonry permits, limits). Masonry work in Chicago calls for a City licensed mason contractor (mason license). Confirm current rules with the Department of Buildings before work starts.
We won't put a number on it, because it depends on the building. What moves it: how much of the wall has failed, how high the work is and what scaffolding that takes, whether lintels or the parapet are involved, how much brick has to be replaced and matched, and whether the porch is part of the job.
What happens if you wait?
Water damage compounds, and so does what the City can cite. The exterior maintenance rule applies whether or not anyone has complained yet, and most violations on occupied buildings start with a 311 complaint (City of Chicago). Falling masonry is the worst version. In July 2016, bricks fell from a two-family home on Chicago's West Side and injured two passersby (ABC7). In another case, City records for a West Englewood church facade collapse cited failure to maintain exterior walls and a lintel, and the owner faced prosecution (CBS Chicago). A small repair done early costs less in work and in risk than the same repair done after something falls.
The City's high-rise Exterior Wall Program does not apply to a typical two-flat, but the maintenance rule does. A two-flat is still the owner's responsibility, tenants or not.
Not sure how bad your two-flat is?
Akats is a family-operated Chicago contractor, licensed and insured in Illinois, and bilingual in English and Spanish. Masonry, tuckpointing, porches, roofing and violations are all handled in-house, so one crew can read the whole building instead of one trade at a time. See our masonry services and ask for a free estimate. We will walk the outside, tell you what is urgent and what can wait. If you are buying, see what to check outside a two-flat first.
Common questions
Open or crumbling mortar joints, spalling brick faces, cracked or rusted lintels, a loose parapet or coping at the roofline, and a rear porch that has moved or rotted. They are connected, because water entering at one spot damages the next. See what a two-flat needs from its owner.
Scrape a joint with a key. If the mortar crumbles, is sandy, is recessed or is missing, the joint has failed. White staining and flaking brick faces usually mean water is already moving through the wall. A mason should look at it before anything is patched.
Treat it as urgent. A wall that bulges or leans, or brick that is falling, is a safety issue for tenants and for people on the sidewalk. Keep people away from the area and call a licensed contractor or an engineer. If you think the building is unsafe, you can also report it to 311.
Sources
- City of Chicago: Code Modernization Ordinance, including Title 14X Minimum Requirements for Existing Buildings (PDF)
- CBS News Chicago: South Side church collapse coverage
- ABC7 Chicago: Building bricks collapse, injure 2 on West Side (July 25, 2016)
- City of Chicago: Express Permit Program: Masonry Work
- City of Chicago, Department of Buildings: Mason Contractor License
- National Park Service: Preservation Brief 2: Repointing Mortar Joints in Historic Masonry Buildings (PDF)
- Brick Industry Association: Technical Note 31B: Structural Steel Lintels (PDF)
- City of Chicago, Department of Buildings and Department of Law: Building Code Violation Enforcement Process (PDF)
Facts last checked: October 7, 2026.
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.