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Gypsum concrete underlayment

Gypsum concrete underlayment rough-in inspection checklist

Gypsum concrete underlayment rough-in is the last time the work is fully visible. Once the cover inspection passes and the walls, ceilings and slabs close, every defect left behind becomes a demolition bill. This checklist walks the rough-in in the order the work goes in, with the photo each item needs before it gets buried. Work is commonly verified against manufacturer's published instructions. Confirm the edition your authority having jurisdiction has adopted.

Items
5
Photos required
9

Who runs it

The underlayment crew lead walking the floor ahead of the pump, with the GC's superintendent releasing the area.

When in the schedule

After the subfloor is fastened and dry and penetrations are set, and before the pour, since none of the prep can be inspected once the slurry covers it.

The checklist

Every item, and the photo that proves it

The photo count on each row is what RTI would require before the item can be submitted. Copy the list as is, or load it into RTI and let the gate enforce it.

01

Substrate and deck

  • Subfloor sound, dry and fastened off

    Plywood or concrete deck solid with no loose or springy areas, fasteners set, surface dry and swept clean of debris.

    2 photos
  • Primer applied where required

    Primer coating the deck evenly per the manufacturer, wood substrates sealed so they don't rob water from the pour, no bare patches.

    1 photo
02

Sound mat and depth

  • Sound mat laid flat with seams treated where specified

    Mat continuous and uncrushed, seams butted or taped per the detail, turned up at walls so the pour doesn't bridge to structure.

    2 photos
  • Depth pins or pour height set to the specified thickness

    Screed pins or reference marks set so the finished pour meets the required thickness over the high point of the deck or mat.

    2 photos
03

Containment

  • Penetrations and edges dammed

    Pipe penetrations, floor drains, door thresholds and unit boundaries dammed so the slurry can't run through or off the floor.

    2 photos

What usually sends this back

The failures are almost always the evidence, not the work

  • Poured over a bare, unprimed wood deck so the underside dries too fast and the bond and surface suffer.
  • Sound mat seams left open or the mat crushed by traffic, so the acoustic rating and pour depth are both off.
  • Floor penetrations and unit-to-corridor edges not dammed, so the slurry runs into the ceiling below or out the door.

Run it with the Photo Gate

A checklist nobody can submit half-finished

Load this list into RTI, stick a QR tag on the area it covers, and the submit button stays locked until every mandatory item is answered and the 9 required photos exist. Approved walks roll into a branded turnover package with a tamper-evident record behind every line.

Submission state

Mandatory items answered5 of 5
Photos attached6 of 9
Submit locked, 3 photos missing

The gate is enforced on the server, so it holds even if the phone is offline when the walk happens.

Common questions

What does this gypsum concrete underlayment rough-in checklist cover?
5 items across 3 sections, covering substrate and deck, sound mat and depth, containment. Each item spells out what the person walking the job is actually looking for, not just a box to tick.
Who should run this inspection?
The underlayment crew lead walking the floor ahead of the pump, with the GC's superintendent releasing the area.
When in the schedule should this walk happen?
After the subfloor is fastened and dry and penetrations are set, and before the pour, since none of the prep can be inspected once the slurry covers it.
Why does every item ask for a photo?
9 of the 5 items call for photo evidence. A checklist answer without the photo is a claim; the photo is what makes the record worth something in a dispute and lets a reviewer approve work without re-walking the job.
What most often fails a gypsum concrete underlayment rough-in inspection?
Poured over a bare, unprimed wood deck so the underside dries too fast and the bond and surface suffer. Sound mat seams left open or the mat crushed by traffic, so the acoustic rating and pour depth are both off. Floor penetrations and unit-to-corridor edges not dammed, so the slurry runs into the ceiling below or out the door.
Can I use this checklist in RTI?
Yes. Start a free RTI workspace, build this list as a checklist, and the Photo Gate holds the submit button until every mandatory item is answered and its photos are attached. Approved inspections roll into a branded turnover package with a tamper-evident audit trail.