Trade walkthroughs
How to inspect a flooring installation
Almost every flooring failure traces back to something under the finish — a slab that was too wet, a substrate that was too far out of flat, a prep step that got skipped to make the schedule. This walkthrough starts where the failures start, at the substrate, and works up to the finished floor, because once the material is down the only honest record is the one you took on the way there.
For the flooring foreman and the GC's superintendent verifying substrate readiness and the finished install before the space is turned over.
Step by step
Test the substrate for moisture
Confirm the slab or subfloor moisture is within the flooring manufacturer's limit, tested by the method they require and recorded before any material goes down. A floor installed over a slab above its moisture limit is a warranty problem waiting to happen.
Check substrate flatness and soundness
The substrate should be flat within the tolerance the flooring calls for, sound, clean and free of curing compounds or bond breakers. Straightedge the areas that look off — a hump or dip telegraphs straight through resilient and tile alike.
Verify prep and any moisture mitigation
Where the substrate needed patching, grinding, a primer, or a moisture-mitigation coating, confirm it was done and cured per the manufacturer before the finish goes down. This is the step that quietly gets skipped under schedule pressure.
Inspect adhesion and installation
Look for full adhesive transfer, no hollow spots, tight seams, and expansion gaps where the assembly needs to move. Check that the trowel, adhesive and open time match what the manufacturer specified.
Verify the finished floor and protection
The finished floor should be flat, clean, free of gaps, lippage and telegraphed defects, with transitions and base tied in. Confirm it is protected from the trades still working above it before you move on.
What gets missed
- Installing over a slab that was never moisture-tested, or tested above the manufacturer's limit.
- Skipping the moisture-mitigation or prep step under schedule pressure and burying it under the finish.
- Material never acclimated, so it moves after install and opens the seams.
- Hollow spots from partial adhesive transfer that only show up when the floor is walked.
- No protection over the finished floor while trades keep working above it.
Questions people ask
- Why test the slab for moisture before flooring?
- Because moisture driving up through a slab above the flooring's limit debonds adhesive and buckles the finish, and the manufacturer's warranty typically depends on a recorded test taken before install.
- What tolerance does the substrate have to meet?
- It varies by flooring type — the manufacturer's installation instructions state the flatness tolerance, and thin resilient and large-format tile are the least forgiving, so straightedge the substrate against that number rather than eyeballing 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 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 concrete pourRun the pre-pour inspection, watch the pour, and check the finish — formwork, rebar, embeds, mix, and curing — because concrete only gets inspected once.
- How to inspect painting and coatingsInspect painting and coatings from prep to final coat: substrate readiness, product and system, film build and coverage, and finish, with proof at each stage.
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.