Treat a leaning chimney, or one separating from the house, as a hazard until a mason inspects it above the roof. No one can read a collapse date from the ground, and the lean is usually the last stage of water damage that started higher up. Keep people and cars away from the fall zone, photograph it, and call a licensed mason. If it is moving or dropping bricks, emergency work can start before the permit is filed.
A leaning chimney in Chicago is not a "wait and see" item. Whether it is about to fall is a question only a mason on your roof can answer, and the safe assumption until then is that it could shed bricks at any time. This article covers what to look for, what to do today, and how the repair and permit side works.
How do you tell a leaning chimney from a crooked-looking one?
Old chimneys are never perfectly plumb, and a stack that looks off from one angle may be fine from another. These signs mean the lean is real and active:
- A gap between the chimney and the house wall that is visible from the yard or the roof, or one that is wider than it was a season ago.
- A visible bow or curve in the stack, with the top courses sitting out past the bottom ones.
- Horizontal cracks across the shaft, or bricks that have shifted out of line with their neighbors.
- Loose or missing bricks at the top, or brick pieces and mortar grit on the roof, in the gutters or in the yard.
- Daylight, or a loose-looking joint, where the chimney meets the roof and the flashing has pulled away.
Take a photo from the same spot every few days. If the gap grows or pieces keep dropping, it is moving, and that changes how fast you need a mason.
Why do chimneys lean or pull away from the house?
A chimney is the most exposed masonry on the building. It stands above the roof with weather on all four sides. The Brick Industry Association says flashing belongs where a chimney meets the roof, and that caps and copings exist to channel water away, with brick caps full of mortar joints a weak choice at an exposed spot (BIA, BIA).
When that protection fails, water gets into the brick and the joints. Saturated brick can spall or delaminate from freeze-thaw cycling or from salts crystallizing inside it (NPS and BIA). The top of the stack usually goes first, and the damage works downward. A visible lean tells you the structure has already lost a lot. What exactly moved, and why, is something we only call after looking at the stack up close. A photo from the ground is not enough to guess.
On older Chicago two-flats and bungalows, the chimney that leans is often one nobody has looked at in years. The cap is cracked, the top courses are loose, and the flashing at the roof line has opened. The lean shows up after the water damage, not before it.
What should you do today?
- Keep people and cars out of the fall zone. That means the yard, gangway, alley or sidewalk below the chimney, and the roof around it. If it could land on a neighbor's property, tell them.
- Do not climb up to look, and do not push on it. Photograph it from the ground and from any safe window.
- Do not patch it yourself. Caulk or a tube of mortar on a moving stack hides the problem and does not fix it.
- Call a licensed mason now, and say it is leaning or separating so it gets seen first.
- If it is dropping bricks or visibly shifting, call 911 and clear the area. Do not wait for a contractor's schedule.
Who fixes it, and what does the City say?
Leaning, bowed or separating stacks are usually rebuilt, at least from the damaged section up. Our chimney repair or rebuild article lays out when a repair is enough and when it is not. If the top is the problem, see chimney crown repair. If you no longer use the chimney, the other path is removing it, which is a separate permit question.
The City's maintenance rules apply here. They require the exterior of a structure to be kept in good repair and structurally sound, and they list veneer, trim and facings that are not properly anchored as unsafe conditions (City of Chicago). A chimney is not named on that list, but a leaning stack is the kind of problem that rule is aimed at, so do not let it sit.
On permits: if a chimney is an immediate hazard, emergency work that normally needs a permit can be done first. The application is due the next business day, and emergency scaffolding needs an application within 3 business days (City of Chicago). Scaffolding or a dumpster on the sidewalk, alley or parkway needs its own permit from CDOT (City of Chicago). For non-emergency rebuilds, confirm the route with the Department of Buildings.
Our work is the brick. Whether the flue is lined and safe for your heating appliance is a different inspection. Ask a chimney or heating professional about that.
Got a chimney that is leaning, bowed or shedding bricks? Akats is licensed and insured in Illinois, and we handle the masonry and the permit paperwork. See our masonry service or read the Chicago brick and masonry repair guide.
Common questions
No one can give an honest date from the ground. Some stay put for a long time and some drop bricks in the next storm. Treat it as a hazard, keep the area below clear, and have a licensed mason inspect it above the roof.
A stack that is leaning or separating is usually taken down to sound brick and rebuilt, not pushed back into place. Only a mason who has seen it up close can say how much has to come down.
It can be, especially if the gap is growing or bricks are coming off. Clear the area below and call a mason right away. Emergency work can start before the permit, with the application due the next business day.
Sources
- City of Chicago: Code Modernization Ordinance, including Title 14X Minimum Requirements for Existing Buildings (PDF)
- City of Chicago: Guide to Building Permits: What Types of Work Do Not Require a Building Permit?
- Brick Industry Association: Technical Note 7: Water Penetration Resistance, Design and Detailing (PDF)
- Brick Industry Association: Technical Note 36A: Caps and Copings, Corbels and Racking (PDF)
- National Park Service: Preservation Brief 2: Repointing Mortar Joints in Historic Masonry Buildings (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.