Problems guides

Read the crack before you read the quote

Most foundation problems announce themselves long before anything structural fails: a crack that widens, a door that stops closing, a floor that slopes toward one corner. The diagnosis is in the pattern, the direction and the rate of change — not in the size of the crack alone.

Symptom	Likely cause	What proves it	Typical response
Vertical crack in a basement wall	Concrete shrinkage, often harmless	Width stable over 12 months; no displacement	Epoxy or polyurethane injection if leaking
Stair-step crack in block	Differential settlement of a footing	Level survey; crack monitor	Piers under the settled corner
Horizontal crack in a block wall	Lateral soil pressure, bowing	Plumb measurement; wall survey	Carbon fibre, anchors or rebuild
Doors and windows stick	Frame racking from movement	Check square of openings; floor level	Diagnose the cause before adjusting
Sloping or bouncy floor	Joist or footing settlement	Crawl space inspection; laser level	Piers, joist repair or slab lifting
Water in the crawl space	Grading, downspouts, water table	Moisture readings; drainage survey	Drainage first, encapsulation second
Gap between wall and ceiling	Framing movement or settlement	Measurement over time	Engineer if growing

The three measurements that matter

Width. A hairline crack under 1/16 inch that has not changed in a year is usually cosmetic. A crack over 1/8 inch, or one that has widened since you last looked, is worth an engineer.

Displacement. Run a finger across the crack. If one side is proud of the other, the wall has moved in or out of plane — that is a structural signal, not a cosmetic one.

Rate. Install a $20 crack monitor and read it monthly. A crack that moves 1/16 inch in a season is a different problem from one that moved in 2015 and stopped.

What NOT to do first

• Do not patch a moving crack with hydraulic cement and call it repaired — it will reopen and hide the evidence.
• Do not let a contractor quote piers before anyone has measured floor levels or inspected the crawl space.
• Do not treat a wet basement as a structural problem until drainage is fixed; water is often the cause, not the symptom.
• Do not accept "all houses settle" as an answer to a crack that is actively widening.

Symptoms that are not foundation problems

Sticking doors in a humid summer, a crack above a doorway from a previous renovation, and a slab crack that follows a control joint are usually not structural. The test is whether the movement is progressive and whether it is tied to a load path. A $300 engineer's inspection is cheaper than a $12,000 pier system sold to fix a humidity problem.

The foundation types hub explains which failures belong to slab, crawl space, basement and pier-and-beam construction, and the repair methods hub covers what each fix does. Start with the crack types guide if the symptom is a visible line.

When should I worry about a foundation crack?

When it is wider than 1/8 inch, when one side is displaced, when it is horizontal in a block wall, or when it is growing. Width alone is not the test — change over time is.

Can a foundation problem fix itself?

No. Soil movement can pause in a dry season, but the void and the lost bearing capacity remain. Monitoring is reasonable; assuming it is over is not.

How much does an inspection cost?

A structural engineer typically charges $400–$1,500 for a site visit and a stamped letter. Contractor inspections are usually free — and usually end in a quote, which is why the independent letter matters.