Structural problems

What counts as a structural defect

A structural defect affects a building's load-bearing capacity: its foundation, framing, slab, or the connections between them. Industry practice describes a structural defect broadly as a deficiency that leads to failure, a shorter service life, or substandard performance, per Knott Laboratory's construction defect glossary.

The same design versus workmanship split that applies to any defect applies here too. A beam sized wrong on the drawings is a design defect, a beam installed out of plumb from a correct drawing is a workmanship defect. See Design defect vs workmanship defect for how that distinction changes who is responsible.

"Foundations, load bearing components, and slabs, shall not contain significant cracks or significant vertical displacement."

Source: California Civil Code, Right to Repair Act, section 896, California Legislative Information

That exact language is California's Right to Repair Act only. Most states have no equivalent enumerated structural standard, check whether your state has one before assuming it does.

Why a crack's width does not tell you the answer

Boards commonly want a number: how wide is too wide, how much settling is too much. Beyond California's own statute above, no reliable, independently verifiable structural threshold turned up in this research, and specific crack-width claims circulated by repair firms could not be confirmed against any code. Treat any such number you find online with suspicion.

What does exist is a recognized discipline for answering the question properly. A forensic engineer applies engineering principles to investigate a failure or performance problem, often with an eye toward testifying about the findings later, per the American Society of Civil Engineers' Forensic Engineering Division.

Florida's engineering board defines professional negligence for engineers as failing to use due care measured against accepted engineering principles; other states define it in their own regulations. The upshot for a board is the same everywhere: hire someone licensed and accountable to a state board, not an unlicensed inspector.

What a structural investigation actually looks like

A competent investigation follows a sequence, not a single walk-through. One licensed forensic engineer describes it as document and contract review, a site visit, and comparing the actual scope of work against the contract documents to isolate the cause, per CLM Magazine. Another account lays out four stages: site inspection and documentation, evidence collection and testing, data analysis to find the root cause, and a written expert report, per CED Technologies.

That sequence sometimes requires opening a wall or slab to see what is underneath. See Destructive testing for what that involves. For the full process, from planning through serving as an expert witness, see Expert investigations. Ask your engineer for a formal written report, not just a verbal opinion, so the association has something usable if the matter becomes a claim, consistent with the reporting scope in ASTM's standard for expert opinions.