Start by finding out whether the brick holds the house up or only covers it. Solid masonry walls in many older houses are load-bearing; most newer brick is a single veneer layer tied to a wood-framed wall that carries the load. Stair-step cracks, bulges, cracks above windows and a leaning chimney all point to movement or failing ties and need a mason, and often an engineer.
- Solid masonry walls carry floors and roofs; brick veneer carries only itself and depends on ties to the frame behind it.
- Stair-step cracks along mortar joints usually mean differential movement of the foundation below them.
- Cracks fanning out above windows and doors often come from a rusting or sagging steel lintel.
- A chimney that leans away from the house is a settling or failing footing until proven otherwise; keep people clear of the fall zone.
- Old brick needs mortar softer than the brick; hard modern mortar can push damage into the bricks themselves.
01 /Is a brick wall load-bearing or a veneer?
Both kinds look like brick from the sidewalk, but they are different structures. A solid masonry wall is two or more layers of brick, called wythes, bonded together; the floor joists and roof bear on it, so it is the structure. Brick veneer is a single wythe standing a short distance in front of a wood-framed wall, held to that frame with metal ties; the wood frame carries the house and the brick carries only its own weight down to the foundation.
Era is a clue, not a rule. Many houses in Canada's older neighbourhoods were built with solid masonry walls, while wood frame with a brick veneer became the norm for later houses. But an early National Research Council note on 19th-century Ottawa houses recorded both a cavity wall whose inner wythe alone carried the second floor, and a brick veneer over a wood frame on a house of about the same age. Look at the wall itself.
| Clue | Solid masonry (load-bearing) | Brick veneer (cladding) |
|---|---|---|
| Bond pattern outside | Often rows of bricks turned end-out (headers) every few courses, tying the wythes | Usually all long faces (stretchers); no headers |
| Wall thickness at a window or door | Thick, often two bricks or more deep | One brick plus an air space and a framed wall |
| Inside finish | Plaster often applied directly to the brick | Drywall or lath on wood studs |
| Bottom of the wall | Usually no weep holes | Weep holes or vents above the foundation in many cases |
| What the joists rest on | Joist ends pocketed into the brick | A wood sill and rim on the foundation |
A few old houses hide their bonding inside the wall, so a veneer-like face does not prove the wall is veneer. When in doubt, an engineer or an experienced mason can confirm from inside the attic, at a window opening or at the foundation. This matters most before any opening is cut or widened, because cutting a solid masonry wall is cutting the structure; see load-bearing walls for the wood-frame side of the same question.
02 /What do cracks in brick walls mean?
Masonry is strong in compression and weak in tension, so it cracks readily when the ground under it moves, when steel inside it rusts, or when it expands and shrinks with heat and moisture. The pattern tells you which.
| Pattern | Common cause | What to check next |
|---|---|---|
| Stair-step crack along mortar joints | Differential settlement or heave of the foundation | Floors, doors and the foundation below the crack; see settlement |
| Crack widening toward the top of a wall | A corner or end of the house dropping | Whether the foundation corner is settling |
| Cracks fanning from the corners above a window or door | A rusting steel lintel lifting the brick, or a sagging lintel | Rust at the lintel ends, a gap or bow in the mortar joint above the opening |
| Long horizontal crack in veneer | Failing or missing ties, or the frame shrinking or moving behind it | Bulging at that level; whether the brick moves when pushed |
| Vertical crack near a corner in a long wall | Expansion and shrinkage of the masonry with temperature and moisture | Whether it opens and closes seasonally |
| Cracks through bricks rather than joints | Mortar harder than the brick, or heavy local stress | Recent repointing with hard mortar; load concentrated at that spot |
Steel expands as it rusts, and that expansion is strong enough to crack masonry and concrete; National Research Council work on reinforced concrete describes the same mechanism causing cracking and spalling. In many brick houses the lintels over openings are steel angles, and once their ends rust in a wet wall they can lift the brick above them. Stair-step cracks tie back to the foundation; foundation settlement explains the causes and fixes.
03 /Why does a brick wall bulge or lean?
A bulge means a section of masonry has moved out of plane. In solid masonry, the usual story is that the header bricks or ties connecting the wythes have broken or deteriorated, and the outer wythe has separated and started to lean. Walls that have lost their connection to the floor framing, often through rot at the joist pockets, can bow outward over the height of a storey. In veneer, bulges usually mark corroded, missing or poorly embedded ties, sometimes combined with water trapped behind the brick and freeze-thaw damage.
Repairs range from retrofit ties drilled through the veneer into the frame behind, to taking down and rebuilding the bulged section, to engineered anchors that tie solid masonry back to the floors. The right answer depends on why the wall moved, so an assessment comes before any quote you can compare.
04 /What does a leaning chimney mean?
A masonry chimney is one of the heaviest parts of a house, and many sit on their own footing. When that footing is shallow, undersized or on soil that settles or heaves, the chimney tilts, most often away from the house, opening a gap between chimney and wall. The Structural Warning Sign Triage weights a leaning chimney at 3 for exactly that reason: it usually means the support under a concentrated load has moved.
- Gap at the wall or roof. The chimney is moving independently of the house; flashing tears and water gets in.
- Cracked crown or cap and loose mortar near the top. Water enters the masonry, and freeze-thaw cycles break it down from the top.
- Bricks at the roofline displaced or missing. The part above the roof is most exposed and least supported.
- Cracks or leaning inside the attic. Mortar in older chimneys can erode where it is out of sight.
- Signs of a chimney fire or a damaged liner. Have the flue inspected before using the fireplace or appliance again.
A leaning or separating chimney is both a structural and a safety issue. Falling masonry is the obvious risk; a less visible one is a cracked or separated flue that can leak combustion gases into the house. Stop using the fireplace or appliance connected to it until a qualified chimney inspector and, for the tilt, an engineer or mason have looked. Make sure carbon monoxide alarms are working.
Fixes depend on the cause and on whether the chimney is still needed. They include underpinning or replacing the chimney footing, rebuilding the section above the roof, bracing it to the house to an engineered detail, and removing an unused chimney, which is itself structural work if the chimney supports or is supported by framing.
05 /How are brick walls and chimneys repaired?
- Find the cause
Crack mapping, a look at the foundation below, lintel ends, ties and joist pockets. For bulges, stair-step cracks and leaning chimneys, an engineer's letter on cause is worth having before any repair is priced.
- Deal with water
Flashing, gutters, downspouts, chimney crowns and grading. Most masonry decay is water plus freezing.
- Fix the support
Underpin a settling footing, replace a rusted lintel with temporary support in place, or install retrofit ties or anchors.
- Rebuild or stitch
Rebuild displaced or bulged sections; stitch cracked brickwork with reinforcement set into the joints where the engineer or mason specifies it.
- Repoint with compatible mortar
Replace deteriorated mortar with a mix matched to the brick and the original mortar, applied to the right depth.
Mortar choice is where well-meant repairs go wrong. Older brick walls were laid in soft, lime-rich mortar that was meant to be the weaker, sacrificial part of the wall, absorbing movement and letting moisture out. A National Research Council paper on repointing older masonry warns that inappropriate repointing materials and practices can permanently damage older masonry assemblies. In practice that usually means a very hard, cement-rich mortar pushed into soft old brick, which forces cracking and spalling into the bricks themselves. People searching for the best brick or the best structural repair mortar are asking the right question the wrong way: the best choice is the one compatible with what is already in the wall.
06 /Who should you call, and what will it cost?
For a crumbling chimney top or open mortar joints, a mason is the right first call. For a bulging wall, cracks that follow a foundation corner, a lintel over a wide opening, a leaning chimney or any plan to cut an opening in solid masonry, start with a structural engineer and let the engineer's letter define the mason's scope. The what a structural engineer does guide explains how to hire one.
| Service | Typical planning range |
|---|---|
| Site visit and short letter on cause | $500–$1,500 |
| Detailed assessment report | $1,200–$3,000 |
| Field review visit during repairs | $250–$750 per visit |
Photograph the cracks with a tape measure in the frame and date them, then again after a season. For next steps, send a request with those photos and a picture of the whole wall or chimney. StructuralRepair.ca is part of HAUSE Home, an independent information and service-request network, not a masonry contractor or engineering firm. Costs for the related foundation work are in the structural repair cost guide.
FAQQuestions people ask
Is brick veneer load-bearing?
No. Veneer is a single layer of brick tied to a wood-framed wall, and it carries only its own weight. The framed wall behind it carries the floors and roof. Solid masonry walls in older houses are a different case: they are the structure.
Are stair-step cracks in a brick wall serious?
They are worth investigating because they usually mean part of the foundation has moved. Fine, old, stable cracks are often monitored; wide cracks, offset bricks or cracks that are growing call for an engineer.
Can a leaning chimney fall over?
It can, especially if the lean is increasing, the mortar is failing or the chimney has separated from the house. Keep people out of the area it could fall into, stop using it and have it assessed promptly.
Should old brick be repointed with modern mortar?
Not with a hard, cement-rich mix. Older brick generally needs a softer mortar matched to the brick and the original mortar, so the mortar rather than the brick takes the wear. A mason experienced with older masonry should choose the mix.
Why is the brick above my window cracked?
Often the steel lintel over the opening is rusting and lifting the brick, or it has sagged. Look for rust at the lintel ends and a stepped or bowed mortar joint above the opening, and have a mason or engineer assess it.
Can I remove an unused chimney?
Often, but it is structural work. Chimneys can support framing or be tied into it, and removal usually needs a permit plus patching of the roof, floors and walls. Get the removal and any new framing planned before demolition.