What does this gypsum concrete underlayment rough-in checklist cover?

15 items across 4 sections, covering substrate and deck, sound mat and depth, containment, materials and pour conditions. 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 do these items ask for a photo?

8 of the 15 items call for photo evidence, 11 photos in all. 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.

Free checklist

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.

Start free with this checklist Download as PDF

The checklist

Every item, and the photo evidence it needs

The photo count on each row is what RTI would require before the item can be submitted. Work the list here and watch the gate hold, or load it into RTI and let it enforce the real thing.

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.
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.
No photo
Primer dry to the manufacturer's pour window
Primer film dry or tacky as the product data describes, not puddled or still wet, and the pour scheduled inside the window the manufacturer gives.
No photo
Deck free of drywall mud, overspray, oil and adhesive
Compound drips, paint overspray, oil and construction adhesive scraped or cleaned off the deck so nothing acts as a bond breaker under the pour.
Deck gaps and holes sealed against slurry drip-through
Open sheathing joints, knot holes and gaps at wall plates filled or taped from above; nothing in the deck lets slurry drop into the ceiling space below.
Floor drains, flanges and floor boxes set to top of pour
Rims of drains, closet flanges and floor boxes checked against the pour depth so they finish flush with the underlayment, not buried or left proud.
No photo

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.
No photo
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.
Top-of-pour height checked against thresholds and sills
Planned pour elevation compared with door thresholds, stair landings and elevator sills so the finished floor stack meets them without a step.
No photo

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.
Pump hose route padded and secured through the building
Hose padded where it crosses finished stairs, window frames or sills and tied off so it can't whip, kink or leak slurry along the route.

Materials and pour conditions

Underlayment and primer on site match the approved submittal
Bag or pallet labels for the gypsum mix and the primer checked against the approved submittal for product name and type before the pump is loaded.
Floor and air temperature within the placing range
Thermometer reading on the floor and in the room within the manufacturer's placing range, openings or temporary heat set so the pour won't freeze or flash-dry.
Buried tubing or heating cable handed off with its test record
Where radiant tubing or cable goes under the pour, its trade's pressure or resistance test record received and the runs looked at for damage before burial.
No photo
Pour sequence and keep-off time agreed with the superintendent
Order of units and corridors set so the crew doesn't pour itself in, and other trades told how long to stay off the floor per the manufacturer.
No photo

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.

Common questions

6 answers

What does this gypsum concrete underlayment rough-in checklist cover?: 15 items across 4 sections, covering substrate and deck, sound mat and depth, containment, materials and pour conditions. 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 do these items ask for a photo?: 8 of the 15 items call for photo evidence, 11 photos in all. 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.

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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 11 required photos exist. Approved walks roll into a branded turnover package with a tamper evident record behind every line.