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How to verify a mock-up

A mock-up is a full-scale sample of a repeating assembly — an exterior wall section, a masonry panel, a window-and-flashing detail, a bathroom — built and approved before production so it becomes the workmanship standard. Verifying one is more than admiring it: it means building it the way the real work will be built, checking it against every requirement, getting the parties who accept it to sign off, and keeping it as the reference. This guide covers running a mock-up so it actually governs the run that follows.

For QC managers, superintendents, and trade foremen setting the workmanship standard for a repeating field assembly before full production begins.

Step by step

  1. Confirm what the mock-up has to demonstrate

    Read the spec section and pull the drawings, approved submittals, and tolerances the mock-up must satisfy. Decide up front what it is meant to prove — the finish, the flashing sequence, the tolerance, the performance — so verification is against a defined list, not a vibe.

  2. Build it under real production conditions

    The mock-up only means something if the production crew builds it with the methods, materials, and equipment they will use on the real work. A mock-up built by the A-team with extra care sets a standard the run cannot hit and is worse than none.

  3. Verify it feature by feature against the requirements

    Go requirement by requirement — dimensions, materials, sequence, finish, and any required performance check like a water test on an exterior assembly. Record the requirement, the observed or measured result, and the disposition for each.

  4. Walk it with the parties who accept it

    Bring the architect, owner, and where relevant the manufacturer and designer to the mock-up, mark it up, correct it, and get formal, written acceptance. Their sign-off is what converts a sample into the governing standard.

  5. Establish the accepted mock-up as the reference

    Once accepted, the mock-up stops being a sample and becomes the benchmark. Keep it standing and protected on site, tagged and dated, and measure the initial phase of the real feature against it.

  6. Protect it and carry the record into turnover

    Guard the mock-up from damage, weathering, or demolition for as long as the work it governs is in progress, and keep the acceptance record. The documented, approved mock-up travels into the turnover package as proof the standard was set and met.

What gets missed

  • Building the mock-up to a higher standard than the production crew can realistically repeat, so the real work looks like a failure against it.
  • Verifying it by eye against a general impression instead of feature by feature against the actual requirements.
  • Skipping the architect's and owner's formal, written acceptance, leaving 'acceptable' undefined when the argument comes later.
  • Tearing down, weathering, or losing the accepted mock-up, so the initial phase has nothing to measure against.
  • Starting the production run before the mock-up is accepted, so a bad detail is already reproduced everywhere.

Questions people ask

What is the difference between a mock-up and a first-article inspection?
They share one intent — set the standard on the first one. A mock-up is a full-scale physical sample of a repeating site assembly, built and approved to become the workmanship reference. A first-article inspection is the full check of the first fabricated or manufactured item against every requirement. Some scopes call for both.
How does an approved mock-up connect to the three phases of control?
The preparatory phase confirms the approved mock-up exists and is the reference before the feature starts, and the initial phase measures the first production run against it. The mock-up is the physical benchmark the phased inspections enforce.

Terms worth knowing

Checklists that make this a one-tap job

Free, field-ready checklists, each with the photo every item needs before it can be submitted.

QC planConstruction quality control planRoles, definable features of work, three-phase control, nonconformance.12 items15 photosITPInspection and test plan (ITP)Activities, acceptance criteria, hold points and the record per row.11 items8 photosMasonryMasonry inspection checklistMortar, reinforcement, grout, flashing and weeps.12 items25 photosCurtain wall Rough-in· Curtain wallCurtain wall rough-in inspection checklistEmbeds, anchors and slab-edge safing verified against the anchor schedule before units are hung6 items12 photos
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Related guides

Reading the steps is one thing. Proving you walked them is the job.

RTI holds the submit button until every mandatory item is answered and the photos are attached, then chains the record so it can be proven untouched later.

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