Trade walkthroughs
How to inspect painting and coatings
Paint is the finish everyone sees and the one whose failures — peeling, flashing, thin coverage — almost always start under it, in prep and conditions nobody documented. This walkthrough follows the coating system the way a good coatings inspector does: verify the substrate and the environment first, then the product, then the film that goes on it, because the surface only tells half the story.
For the painting foreman and the GC's superintendent verifying surface prep, the coating system, and the finished work before acceptance.
Step by step
Verify substrate prep and readiness
The surface should be clean, dry, sound, and prepared to the profile or condition the coating requires — drywall finished to level, metal cleaned, previous coats sound. Coating over a surface that was not prepped is the most common cause of failure.
Confirm conditions are within range
Check that temperature, humidity and dew point are within the manufacturer's window before and during application. Painting outside that range — over a cold or damp substrate — leads to poor adhesion and flashing that shows up weeks later.
Verify primer and inter-coat
Confirm the correct primer went on the correct surface and cured before the topcoat, and that any recoat window was respected. A topcoat rushed over uncured primer or the wrong primer is a delamination waiting to happen.
Inspect film build and coverage
Look for uniform coverage with no thin spots, holidays, runs or roller stipple, and the right number of coats. Where a dry film thickness is specified, confirm it is being measured and recorded, not judged by eye.
Verify the finished appearance and cut lines
The final finish should be uniform in color and sheen, with clean cut lines, no lap marks or flashing, and no overspray on adjacent work. Check it under the lighting it will live under, not just work lights.
What gets missed
- Painting over unsound or unprepped substrate, so the coating fails at the surface it never bonded to.
- Applying outside the temperature, humidity or dew-point window and getting flashing or poor adhesion weeks later.
- Wrong primer for the substrate, or a topcoat rushed over primer that had not cured.
- Thin or uneven film judged by eye where a dry film thickness was actually specified.
- Signing off under work lights, so lap marks and sheen variation only appear under the finished lighting.
Questions people ask
- Why do conditions matter as much as the paint?
- Because a coating applied over a cold or damp substrate or outside the manufacturer's temperature and humidity window will not cure or bond properly, and the failure — flashing, peeling, poor hide — shows up after the painters are gone.
- How is coverage verified beyond a look?
- By the number of coats against the approved system and, where a dry film thickness is specified, an actual measured and recorded reading — coverage judged only by eye is how thin spots and holidays get buried under an acceptable-looking sheen.
Standards behind it
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.
Related guides
- How to inspect drywall before closeRun the pre-drywall walk while the walls are open, then inspect board install: backing, fastening, board type, joints and finish level, with proof at each stage.
- How to inspect tile workInspect tile work from substrate and waterproofing up through layout, setting bed, grout and finish, catching the failures that hide before the tile goes on.
- How to inspect a flooring installationInspect a flooring install from the substrate up: moisture and flatness, prep, layout, adhesion and finish, with the readings and photos each stage needs.
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.