What Is QA/QC in Construction?

QA/QC gets used as one phrase so often that the distinction inside it tends to get lost. They're related but they're not the same thing, and knowing which is which matters for figuring out who's responsible for what.

Quality Assurance: The System

Quality assurance is the process side. It's the procedures, standards, and review steps put in place before work happens, meant to prevent problems rather than catch them after the fact. In design, that looks like coordination reviews, documentation standards, and constructability checks built into the workflow before drawings go out. QA is about setting up the conditions where quality is likely, not verifying it after the fact.

Quality Control: The Verification

Quality control is what checks the actual output against those standards. On the design side, that's reviewing drawings and specs to confirm they meet the QA process's own requirements. Once construction starts, QC shifts to physical verification: inspections, material testing, and confirming installed work actually matches what was designed and specified.

A simple way to hold the distinction: QA asks "did we follow a good process?" QC asks "does the actual result meet the standard?" A project can have a strong QA process and still turn up QC failures if the process wasn't followed carefully, or if something slipped through despite a reasonable process.

Who's Responsible for What

Responsibility for QA/QC is genuinely shared, not owned by one party. Architects and engineers establish quality standards in the contract documents and review submittals. Contractors are typically responsible for quality control during construction, which includes supervising the work, coordinating inspections and testing, and managing subcontractor quality. Owners set the project's quality goals and sometimes bring in special inspectors for particularly high-risk elements. A construction manager, if one is on the project, often coordinates the overall QA/QC program across all these parties.

Where This Shows Up in a Drawing Set

Documentation QA/QC happens before anything is built. It covers things like verifying technical accuracy across plans, sections, and details, coordinating specs with drawings to prevent conflicts, and running interdisciplinary coordination reviews so architectural, structural, and MEP drawings actually agree with each other. A breakdown here tends to cascade: a coordination gap missed during design QA often turns into an RFI, a change order, or rework once it's discovered in the field, at a much higher cost than it would have taken to catch on paper.

Why AI-Assisted Review Fits Into the QA Side, Not QC

Tools like Structured AI's QA/QC Compliance Checks operate on the design-phase QA side: catching code, coordination, and spec-drawing conflicts before a set goes out, so the field-side QC process starts from cleaner documents. It's a pre-construction check, not a substitute for on-site inspection or material testing, which remain QC activities that happen once work is actually being built.

FAQ

Is QA/QC one department or role, or is it distributed? It's distributed. Architects, engineers, contractors, and owners each carry some piece of responsibility, and larger firms or projects often have a dedicated QA/QC lead or program to coordinate across all of them.

Does QA/QC only apply to large commercial projects? No, though the formality of the process tends to scale with project size and complexity. Even smaller residential projects benefit from basic QA steps like coordination checks, even if they don't have a formal documented QA/QC program.

How does AI fit into a firm's existing QA/QC program? It's typically layered into the design-phase QA process as an automated first pass, catching coordination and code issues before human review, rather than replacing the review process entirely.