Are vertical or zig-zag cracks in a masonry / brick exterior wall something to worry about?

A zig-zag (stair-step) crack that follows the mortar joints in a brick or block wall usually means the foundation under that wall has moved, and you want it looked at. A straight vertical hairline crack is often less urgent. We give a free inspection and a written estimate, and most foundation crack repairs fall in the $1,000 to $3,000 range depending on what is moving and why.

Here is the plain version. Brick and block walls do not bend. So when the ground under them shifts, the wall cracks where it is weakest, which is the mortar. A zig-zag crack steps up through those joints. That stair-step pattern is the tell. It says one part of the footing has dropped or lifted while the rest stayed put.

Why does the ground move here? Two big reasons in New Hampshire. One is disturbed backfill. When your house was built, the crew dug a hole, poured the foundation, then pushed the dirt back in. That backfill is looser than the packed soil around it. It drains slow and holds water. Wet soil swells, dry soil shrinks, and the footing rides up and down with it. The other reason is frost. Our winters freeze the ground deep. Frozen soil expands and pushes on the wall. Then it thaws and lets go. Year after year, that push and release can crack masonry.

A straight vertical crack is a different story. Brick and concrete shrink a little as they cure and settle a little in the first years. A thin vertical line, no wider than a coin edge, often comes from that. You may not need anything done yet. We will tell you that to your face. If we look and the crack is stable and tight, we say so.

The ones we watch closely:

• Stair-step cracks wider than about a quarter inch.
• Cracks that are wider at the top than the bottom, or the reverse.
• Brick that bows out, sticks out, or steps in.
• A crack that grows. Mark the ends with a pencil and a date. If it moves, call us.
• Doors and windows nearby that suddenly stick.

What fixes it depends on the cause, and that is why we look before we quote. If a poured wall has cracked and is leaking or moving a little, crack injection seals it, usually around $1,000 to $3,000. If a wall is bowing inward from soil and frost pressure, carbon-fiber straps hold it flat, around $850 each, or a power brace for more push, around $1,300 per brace. If the footing itself has settled and the whole wall is dropping, that is a support problem. Helical piers go down to solid ground and lift the footing back, around $2,700 per pier for the first three, then $2,200 per pier after that. We self-perform our structural lifting and helical work in-house, so the crew at your house is our crew.

Some jobs we will not price over the phone or on a page. A full foundation-wall rebuild or replacement, wall anchors, or steel I-beams. We price that after we see it. There is no fair number until we know how far the wall has moved and what is causing it. We do repair, not new foundations, so if a wall is too far gone we will tell you what repair can and cannot do.

One thing we do not do is dig up the outside and tar the wall. In our field experience that exterior excavation fix tends to fail in a couple of years. The water comes back. For water that is also showing up inside, the durable fix is interior drainage, our basement waterproofing work, not an outside dig.

A note on insurance. Most homeowner policies do not cover foundation movement from settling or frost. For how that works, the Insurance Information Institute explains standard policy coverage [verify]. Read your policy before you assume it is covered.

If you see a stair-step crack, do not panic and do not ignore it. Have someone who works on these every day take a look. We will tell you whether it is cosmetic or structural, and we will put it in writing.

Want eyes on it? Call us at 603-610-1770 or book your free inspection. Free inspection, free estimate, and a quote within 24 hours. Every structural repair we do is backed by the 603 guarantee, with 25-year warranties on carbon-fiber wall stabilization and helical piers.

Related questions

Is a stair-step crack in my brick worse than a straight vertical crack? Usually, yes. A stair-step crack through the mortar joints points to footing movement underneath. A thin straight vertical crack is more often shrinkage or minor settling. We confirm which one you have with a free inspection. See our structural and foundation repair work.

Can you fix a bowing brick or block wall without rebuilding it? Often, yes. Carbon-fiber straps hold a bowing wall flat, around $850 each, and a power brace adds more support, around $1,300 per brace. Rebuilds are rare and we price those after we see the wall. More on supplemental support.

Does crack repair stop the water coming through too? Crack injection seals the crack, usually around $1,000 to $3,000. If water is also coming up at the floor wall joint, that is a drainage issue and you may want our basement waterproofing work instead.

How fast can you come look? We give a free inspection and a written estimate, with a quote within 24 hours. Call 603-610-1770 or book your free inspection.