Here is what to check, in order, starting from the roof down. This is a practical spring masonry inspection checklist you can work through in an afternoon with binoculars and a flashlight. Chicagoland sits in one of the highest freeze-thaw cycle zones in the continental U.S. per GLISA Great Lakes climate analysis. The damage is done. Now you read it. The National Weather Service for Chicago records the typical end-of-freeze date, and your masonry holds the record of what came before it.
1. Chimney Crown
What it is: The concrete or mortar cap at the very top of the chimney structure, covering the space between the flue liner and the outer walls.
Stand back with binoculars. Look for cracks running across the crown surface, missing chunks, visible gaps where the crown meets the flue liner collar, or any vegetation growing from it. Moss and weeds mean the crack has been there long enough to host roots.
In Lake Forest, estates along the ravine bluffs have multi-chimney homes where a single missed crown can let water into an entire masonry stack for multiple winters before interior staining appears. Crown inspection on a Lake Forest home means doing it for each chimney, not just the main one.
Red flag: Any crack you can see from 30 feet away is wide enough to be admitting water with every rain. Crown repair or cap replacement runs $200 to $600 in the Chicagoland market. Water traveling through a failed crown for another winter will cost you multiples of that in masonry repairs below. See spring chimney crown damage: the winter aftermath homeowners miss.
2. Upper Chimney Mortar Joints
What it is: The mortar between the top 15 or so courses of brick, above the roofline.
Scan with binoculars for recessed or missing mortar, crumbling material, or horizontal cracks along individual joint lines. This zone takes the worst freeze-thaw exposure on the entire house.
On Winnetka homes from the 1920s-1940s built with soft Chicago common brick, original lime mortar above the roofline is typically the first zone to fail. The combination of lake-effect wind from the northeast and sustained moisture exposure erodes these joints faster than on any protected wall section. When we find white efflorescence streaking down the chimney face in spring, it almost always traces back to compromised upper chimney joints.
Red flag: Efflorescence streaking down the chimney face from this zone. White staining means water entered through the crown or joints above and traveled down through the brick. See 5 signs your chimney needs immediate repair.
3. Chimney Lean
What it is: The vertical alignment of the chimney stack relative to the house.
Hold a finger up vertically and compare it to the chimney line. Any visible tilt away from the house, or any gap between the chimney and the house siding that is wider at the top than the bottom, means movement has occurred.
Red flag: Any visible lean is an immediate call. This is not a monitor-for-a-season situation. See leaning chimney causes and structural fixes.
4. Exterior Brick Wall Mortar Joints
What it is: The mortar between bricks on all four elevations.
Walk the perimeter slowly. Run your finger along suspect joints. Good mortar is firm and resists light pressure. Bad mortar crumbles or comes out. Focus on the north and east elevations first. They receive more freeze cycles and less drying sun. Also check directly below window sills and above any door or window openings, where water concentrates.
Per BIA Technical Note 7B, mortar recessed more than 3/4 inch from the brick face needs tuckpointing this season. That 3/4-inch depth is both the point where water reaches the back of the joint cavity and the minimum removal depth needed for new mortar to achieve proper mechanical bond.
In Northbrook, homes from the 1960s-1980s building boom were constructed with hard machine-pressed brick and builder-grade mortar that has now reached 40 to 60 years of age. These joints are receding and losing their weather seal at a predictable rate. A Northbrook north elevation that has not been inspected in five years is very likely past the 3/4-inch threshold in at least some courses.
Red flag: Wide-open joints, or joints that have completely washed out in sections. Open joints are direct water pathways into the wall cavity.
5. Brick Face Condition (Spalling)
What it is: The separation and loss of the fired outer surface layer of individual bricks.
Early spalling looks like fine crazing or thin flaking on the brick face. Later stages show concave depressions where the face has broken away, exposing lighter, softer interior material. Spring is when this becomes visible. The freeze-thaw cycle finishes its work during thaw, not during the freeze itself.
On Wilmette homes where prior contractors used hard Portland cement mortar on soft Chicago common brick, spalling on north-facing facades is a consistent spring finding. The NPS Preservation Brief 2 standard is clear: mortar must always be softer than the brick it joins. Where that rule was violated, the brick absorbs the freeze-thaw stress the mortar should have taken, and the face spalls.
Red flag: Fresh spalling with clean fracture edges and light-colored exposed interior means this happened this winter. The exposed brick interior absorbs water at a significantly higher rate than the original fired surface. Every winter you leave it unaddressed, the repair scope grows. See why brick spalling appears in spring.
6. Window and Door Perimeter
What it is: The masonry surrounding all window and door openings.
Look for cracks radiating from window corners at 45-degree angles. Also check for gaps between window frames and the surrounding brick, and for efflorescence on the brick directly below window sills.
In Glencoe, homes near the ravine bluffs with tree canopy shading show persistent efflorescence below window sills on the north and east sides, where shade limits evaporation and moisture accumulates at the sill-to-wall joint.
Red flag: Rust staining on the brick below window or door openings. This indicates the steel lintel inside is corroding and expanding, which cracks the mortar and will eventually displace the brick above it.
7. Foundation Perimeter
What it is: The visible foundation wall above grade, including any parging coat.
Walk the foundation and distinguish crack types. Vertical cracks are common and often not urgent. Horizontal cracks, running across the wall, indicate lateral soil pressure and are more serious. Stair-step cracks following mortar joints diagonally indicate settlement or movement.
If the foundation has a parging coat (smooth mortar plaster applied to the exterior face), check for areas where it has cracked, delaminated, or pulled away from the wall below.
Red flag: Horizontal cracks in a block or brick foundation, especially if one side of the crack is displaced relative to the other. Get professional eyes on this before the next freeze season.
8. Efflorescence on Any Surface
What it is: White, powdery, or crystalline mineral deposits on any masonry surface.
Efflorescence is not a problem in itself. It is a symptom. The white powder tells you where water moved through the masonry and evaporated. Its location points to the water entry pathway. Widespread efflorescence across multiple elevations after a single winter indicates systematic joint failure, not an isolated issue.
In Wilmette, the high water table and lake-proximity humidity make efflorescence on foundation and basement walls particularly common. When we see it on a Wilmette home, it is tracing an active moisture pathway from the saturated soil through the masonry face. See efflorescence and white staining in spring: what it means.
Red flag: Efflorescence that reappears within a week of being cleaned, or efflorescence accompanied by crumbling mortar or spalling in the same area.
9. Concrete Flatwork
What it is: Driveways, walkways, stoops, and garage aprons.
Look for scaling (the surface layer peeling away in irregular patches, exposing aggregate), spalling (deeper chunks breaking out), and linear cracks running parallel to slab edges. Also check control joints, the saw-cut lines in the slab, for failed or missing caulk.
In Northbrook and Glencoe, driveways and entry stoops from the 1970s-1980s that have received heavy de-icing salt application for decades are commonly at the point where surface treatment is no longer adequate. The chloride penetration is too deep, and only replacement addresses the root failure.
Red flag: Long, straight cracks parallel to the driveway edges that do not align with control joints. These may indicate rebar corrosion below the surface from chloride penetration. Tap the surrounding concrete with a screwdriver handle. A hollow sound means delamination below. See spring concrete damage: how to spot de-icer salt failure.
10. Wall Caps and Coping
What it is: The masonry or stone cap on top of any garden wall, retaining wall, or parapet.
Horizontal surfaces collect water. They are the most vulnerable point on any freestanding wall. Check coping stones for cracks or shifted positions, look at the mortar at the cap line for open joints, and scan the wall face just below the cap for efflorescence streaking.
Red flag: A coping stone that has shifted out of position means the mortar joint beneath it has failed. Water is entering the wall from above at that point.
What Comes Next After the Walk-Through
When to call a professional: chimney lean, horizontal foundation cracks, active water in the house near any masonry element, or efflorescence spreading across multiple elevations simultaneously. For timing on scheduling repairs once you have your list, see when to schedule tuckpointing in Illinois: why spring and early summer win.
For the full picture of what Chicago winters do to masonry before the damage becomes visible, read what winter does to Chicago masonry. And if you are scheduling tuckpointing for the first time and want to understand what the repair process involves, see what happens during a tuckpointing job.
Delta - Masonry and Tuckpointing provides free inspections in Winnetka, Wilmette, Glencoe, Lake Forest, Northbrook, and surrounding North Shore and Lake County communities. Call (847) 713-1648 or contact us online.