Construction Quality Assurance: A Practical Guide
Quality problems are cheapest to fix before they're covered up. Construction quality assurance is the system that makes sure someone looks in time.
QA vs QC: the difference
| Quality assurance (QA) | Quality control (QC) | |
|---|---|---|
| Focus | The process | The product |
| Timing | Before and throughout the work | During and after each activity |
| Goal | Prevent defects | Find and fix defects |
| Examples | Quality plan, procedures, submittal review, training, audits | Inspections, material tests, surveys, checklists signed at hold points |
| Typical owner | Quality manager, project management | Site engineers, inspectors, testing labs |
In practice the two are run together as one quality management system. Many contractors base theirs on ISO 9001, and many contracts require a project-specific quality plan.
What goes in a construction QA plan
- Scope and standards: the specifications, codes and client requirements the work must meet.
- Roles: who is responsible for quality, who can stop work, who signs off each inspection.
- Submittal and approval process: shop drawings, material samples, method statements and how they are reviewed.
- Inspection and test plans (ITPs): for each work package, what is checked, when, by whom, against which criteria, and what record is kept.
- Hold and witness points: where work must stop until an inspection is done (hold) or where the client may attend (witness).
- Mock-ups and first-work inspections: a benchmark for acceptable workmanship before work repeats.
- Non-conformance process: how defects are recorded in a non-conformance report (NCR), dispositioned (rework, repair, accept as is, reject) and closed.
- Records: what evidence is kept, where, and for how long.
- Audits and review: how the plan itself is checked and improved.
How to set up QA on a project, step by step
- Read the specification for quality requirements. List every test, inspection, tolerance and submittal the contract asks for.
- Break the work into packages and write an ITP for each: concrete, steel, waterproofing, MEP rough-in, façade and so on.
- Mark hold points before cover-up. Reinforcement before the pour, waterproofing before backfill, services before ceilings close, insulation before boarding.
- Agree acceptance criteria. Tolerances should be numbers from the specification, not "looks fine".
- Build first-work mock-ups and get them approved as the standard.
- Inspect and record as you go. Each record should say what was checked, where, when, by whom and the result, with photos.
- Raise and close NCRs. Track each to a disposition and a verified fix.
- Review trends. If the same defect keeps appearing, fix the process, not just the item.
Construction QA checklist
- Quality plan approved and issued to all trades
- ITPs written for every work package, with hold points marked
- Approved submittals on site before the work starts
- Calibration records for survey and test equipment
- Mock-ups approved and photographed
- Inspections recorded with location, date and photo evidence
- Hidden work recorded before it is covered
- As-built geometry checked against the design model or drawings
- Open NCRs reviewed weekly with owners and due dates
- Quality records filed for handover
Common quality assurance mistakes
- Paper QA. A quality plan written for the tender and never used on site.
- Inspecting too late. Once a ceiling is closed or a slab is poured, the fix is destructive and expensive.
- Records without location. A signed checklist that doesn't say exactly where it applies is weak evidence later.
- NCRs that never close. A long list of open non-conformances is a sign the process is not being followed.
- Relying on the trade's word. "Built to the drawing" should be checked, especially for geometry.
Where SpatialSense fits
SpatialSense supports the record and verification side of QA. It doesn't replace your quality plan or ITPs, but it makes the evidence behind them easier to capture and harder to argue with.
- Check as-built against design. Overlay a scan on the IFC model in the browser (export from Revit to IFC). AI flags deviations and your team confirms them, before finishes hide the problem.
- Record hidden work. A timestamped 360° walk or scan before cover-up is a record of what was there at that date.
- Track non-conformances in place. Pin an issue at the exact point, assign an owner, due date and priority, and track it to resolution.
- Compare dates. Line up two captures of the same area to confirm a fix.
Verify as-built against BIM
Put the scan and the model in the same view and see where they disagree. Scan-to-BIM verification →
Measure in the browser
Check a dimension against a tolerance directly in the viewer. Measure point clouds →
Pin non-conformances
Raise the issue at its location with an owner and a status. Annotate and assign issues →
Capture before cover-up
Timestamped 360° walks of every area, captured with Trace. 360° site documentation →
Frequently asked questions
What is quality assurance in construction?
Quality assurance is the planned system of processes, responsibilities and records that makes sure construction work meets the drawings and specifications. It is preventive and is usually documented in a project quality plan.
What is the difference between QA and QC in construction?
QA is about the process: planning how quality will be achieved and checked. QC is about the product: the inspections and tests that confirm a specific piece of work meets the requirements. QA prevents defects; QC finds them.
What is an inspection and test plan (ITP)?
An ITP lists, for one work package, each inspection or test, when it happens, who does it, the acceptance criteria, whether it is a hold or witness point, and what record is kept.
What is a hold point?
A hold point is a stage where work must stop until a specified inspection is done and signed off, usually because the next activity will cover the work up, such as pouring concrete over reinforcement.
What is an NCR in construction?
A non-conformance report records work or material that doesn't meet requirements. It is reviewed, given a disposition such as rework, repair, accept as is or reject, and closed once the fix is verified.
How does reality capture help construction QA?
Scans and 360° walks give a dated, located record of the work, including work that will later be hidden. Overlaying a scan on the design model shows geometric deviations that are hard to see in photos.
Check the work before it's covered. Start a free trial and overlay your first scan on the BIM model.
14 days free with no credit card, or 30 days free when you book a demo.