Diagonal foundation crack with lateral offset at a 1962 ranch
During a pre-listing inspection of a single-story 1962 ranch on a poured concrete foundation, you find a diagonal crack at the northwest corner of the basement. The crack runs from the top of the foundation wall down toward the corner, is about 1/4 inch wide at its widest point, and the concrete on the outside of the crack is displaced inward about 3/8 inch. The brick veneer above has a matching stair-step crack with a 3/16-inch gap. Inside, the floor slopes about 1 inch over 20 feet toward that corner, and the door at the top of the basement stairs sticks in summer but not winter. The lot slopes toward the house, and a downspout discharges within 12 inches of the foundation. The seller says the crack has been there for years and was caulked twice. You cannot see the footing or the exterior below grade.
1. How would you distinguish among concrete shrinkage, differential settlement, and lateral soil pressure here, and which explanation fits best?
Read the worked answer
Shrinkage cracks are typically vertical or map-cracked, narrow, and show no lateral offset; they do not usually produce a matching brick veneer crack or floor slope. Differential settlement often produces diagonal cracks that are wider at one end, with distortion such as a sloping floor and sticking doors; the corner location, 3/8-inch inward offset, 1-inch floor slope, and downspout discharge all fit that pattern. Lateral soil pressure usually produces a horizontal crack near mid-height of the wall, inward bowing, and sometimes wall movement, but not necessarily a corner diagonal or floor slope. The best fit is corner differential settlement, possibly worsened by roof water at the foundation, but that is a hypothesis, not a diagnosis. Because displacement is present, I would not call it cosmetic. I would report the observed geometry and recommend a licensed structural engineer evaluate the foundation, footing, and drainage before the buyer removes contingencies.
2. What goes in the report, what do you recommend, and what would you deliberately not say?
Read the worked answer
Report measurable facts: diagonal crack at northwest basement corner, up to 1/4 inch wide, 3/8-inch inward displacement, matching stair-step veneer crack, floor slope of about 1 inch in 20 feet, sticking door, and site drainage toward the foundation. State the significance: a displaced foundation crack and veneer crack exceed cosmetic shrinkage and warrant further evaluation. Recommend a licensed structural engineer; separately recommend extending downspouts and correcting grading as water-management maintenance, not as a guaranteed repair. Recommend the seller disclose the crack history and any caulking. Do not say 'the foundation is failing,' do not give a repair cost, and do not say the caulking fixed it. Note limitations: no excavation, no view below grade, no removal of finishes. If the buyer is present, explain that the engineer may recommend monitoring, drainage work, or structural repair depending on findings.
3. The seller's agent asks you to soften the report because the crack was caulked and the buyer is nervous. How do you respond?
Read the worked answer
I would explain that the report describes what I observed and why it matters; caulking hides the crack but does not restore displaced concrete or address the veneer crack. I can correct factual errors or add the seller's documentation, but I cannot change the observation to make the transaction easier. I would offer to review any engineer's report and re-inspect after repairs. If the agent persists, I document the request and keep the original report. This protects the client, the public, and my license; accepting pressure would create a conflict of interest and could mislead the buyer about a safety-related condition.