What Is QA/QC in Construction?

The two halves get conflated constantly, and the conflation is expensive. Quality assurance is what you build before the work starts: the quality plan, the procedures, the standards, the review workflows, the training. Quality control is what you do to the work after it exists: inspect it, test it, measure it against the requirement.

A project with strong QC and weak QA finds a lot of defects. A project with strong QA finds fewer, because fewer were created. Both are necessary, but they are not interchangeable, and a quality program that is all inspection is a program that has decided to pay for rework.

The Inspection and Test Plan is where QA and QC meet in practice. It lists each activity, the standard it is checked against, who performs the check, what evidence gets recorded, and — critically — which points are hold points where work stops until the inspection passes.

Rebar before a pour is the classic example: once the concrete is placed, an error that would have taken an hour to fix becomes a demolition problem. Getting hold points right is the highest-leverage quality decision on most projects, and it happens on paper months before anyone pours anything.

The nonconformance report is the mechanism. An NCR records what deviated, why, and what the corrective action is, and it stays open until the correction is verified. It is the paper trail that proves a defect was found, addressed, and re-checked.

The discipline that separates a functioning quality system from a paperwork exercise is whether nonconformances feed back into the QA side. If the same nonconformance recurs across three projects, the problem is not the crew — it is the procedure or the documentation that led them there.

The same logic applies to documents. Before a set is issued, someone checks that plans, sections, elevations and schedules agree with each other, that keynotes point to the right specification sections, that the fire rating on the plan matches the assembly in the spec, and that code-driven requirements actually appear in the drawings rather than only in the code analysis.

This review is the cheapest quality intervention available on any project, and it is the one most often compressed when a deadline moves. Errors that survive it do not disappear — they reappear as RFIs, as change orders, and occasionally as failed inspections.