Foundation concerns generate more anxiety than almost any other home issue, partly because the consequences can be serious and partly because the field attracts confident sales.
What is usually not serious
Fine vertical cracks in poured concrete are extremely common. Concrete shrinks as it cures and settles slightly as the ground adjusts, and hairline vertical cracking is a normal result.
Minor cracking at the corners of window and door openings in a foundation wall is similarly routine, since those are stress concentration points.
The useful question is not whether cracks exist but what kind, and whether they are changing.
What warrants assessment
Horizontal cracks. These suggest lateral pressure against the wall — soil, water, or both — which is a different mechanism from settlement and more concerning.
Stair-step cracking in block or masonry. Following the mortar joints diagonally, this indicates differential movement.
Width. Cracks noticeably wider than a coin’s thickness are worth looking at properly.
Displacement. Where one side of a crack has moved relative to the other, in or out.
Active widening. The most important signal. Mark a crack with a pencil line across it and note the date. A crack that widens measurably over months is doing something; one that has not moved in a year is probably historic.
The signs upstairs
Foundation movement shows in the house above. Doors and windows that stick or will not latch when they used to. Visible gaps opening between walls and ceilings or at floor junctions. Floors noticeably out of level. Cracks in drywall recurring in the same places after repair.
Individually these have other explanations. Several together, developing over time, point downward.
The Washington context
Most Washington foundation issues relate to water rather than to soil chemistry.
Persistent rainfall, poor drainage, downspouts discharging at the wall and ground sloping toward the house all put water against the foundation. Saturated soil exerts pressure, and repeated wet-dry cycling moves ground.
That is why drainage improvements are frequently part of a foundation solution rather than a separate topic, and why a contractor who assesses foundation concerns without looking at where water goes is missing the likely cause.
East of the Cascades, frost heave is the additional mechanism. Footings that do not extend below frost depth get lifted over successive winters, which is why footing depth requirements there are considerably greater than in the Puget Sound lowlands.
Getting an honest assessment
This is a field where the incentive structure deserves attention. A free inspection from a company selling foundation repair is an assessment by someone whose revenue depends on the answer.
For anything that looks genuinely concerning, a structural engineer who is not selling the remedy gives you an independent opinion. That costs money and is frequently the best money spent, because it tells you both what is happening and what actually needs doing.
Fix the water first
Where drainage is contributing, addressing it comes first. Structural remediation on a foundation still receiving the water that caused the problem addresses the effect rather than the cause.
Any proposal that skips straight to structural work without examining drainage, grading and downspouts is worth questioning.
What to do now
Photograph and date any cracks that concern you. Mark them and check periodically. That record turns a worry into evidence, and it is the single most useful thing a homeowner can do before spending anything.