What does this under-slab vapor retarder pre-pour checklist cover?

14 items across 4 sections, covering continuity and laps, penetrations sealed, damage and edge tie-in, reinforcing and pour protection. 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 concrete foreman placing the retarder with the GC's superintendent, at the hold point right before the pour is released.

When in the schedule should this walk happen?

After the retarder is laid, lapped and reinforcing is set, immediately before concrete is placed, the last moment the sheet is visible.

Why do these items ask for a photo?

9 of the 14 items call for photo evidence, 12 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 an under-slab vapor retarder pre-pour inspection?

Laps left loose or short so the seam opens under crews and vibration and the barrier is no longer continuous under the slab. Pipe and conduit penetrations left with the sheet cut open and no boot or seal, an open hole in the barrier at every stub-up. The retarder torn during rebar and crew traffic and never patched, so the pour buries an unrepaired hole nobody can reach again.

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

Under-slab vapor retarder

Under-slab vapor retarder pre-pour inspection checklist

A under-slab vapor retarder pre-pour inspection is the last look at everything the concrete is about to bury: reinforcement, embeds, sleeves, vapor barrier. Once the truck arrives there is no recheck, so this checklist walks the placement in pour order with the photo each item needs before the pour starts. Work is commonly verified against ASTM vapor retarder standards, ACI concrete guidance, manufacturer's published instructions. Confirm the edition your authority having jurisdiction has adopted.

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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.

Continuity and laps

Sheet continuous with laps sealed to the specified width
Seams overlapped the full specified width and sealed or taped continuously, no open or loose laps, sheet unbroken across the pad.
Sheet flat on the base with no tenting or stretched runs
Sheet in contact with the base across the pad, not tented over stones or trench lines, with slack left at grade changes instead of pulled tight.
Inside and outside corners folded and taped, not slit open
Corners at the perimeter and thickened edges folded or cut and patched as the instructions show, every corner seam taped with no open slit left.
Tape applied within the temperature range on its label
Air and sheet temperature at taping compared with the range on the tape label, and seams kept dry and clean of dust when the tape went on.
No photo

Penetrations sealed

Every penetration booted and sealed to the sheet
Pipes, conduit and stub-ups sealed to the retarder with boots or detailed tape, no open cuts left around any penetration.
Boot collar-to-pipe joint sealed on each penetration
The top of each boot collar taped or clamped to its pipe or conduit per the instructions, with no gap, fishmouth or loose tape where collar meets pipe.
Stub-up count on the pad matches the under-slab layouts
Stub-ups counted against the plumbing and electrical under-slab layouts, each one found booted, so none is buried unsealed under the reinforcing.
No photo

Damage and edge tie-in

Tears patched and the sheet tied in at the perimeter
Traffic tears and punctures patched with matching material, sheet turned up and sealed at the slab edge or footing before the pour is released.
Turn-up held so placement won't drag it into the slab
Sheet at the perimeter taped or fastened to the form or footing face and left long above top of slab, so screeding and vibration can't pull it down.

Reinforcing and pour protection

Chairs and bolsters sit on bases that won't cut the sheet
Chairs under the bar or mesh have plates, sand bases or wide feet as the retarder instructions call for, with no sharp legs pressing into the sheet.
Reinforcing set down on the sheet, not dragged across it
Bar and mesh carried and set onto the pad by the reinforcing crew, not slid or dragged across laps, boots and the turn-up.
No photo
Sheet walked for punctures after reinforcing is placed
Sheet walked once bar or mesh is set; each puncture or tear patched past the damage by the lap the manufacturer lists and taped on every edge.
Screed stakes through the sheet planned for sealing
Grade stakes or screed pins that must pierce the sheet agreed with the concrete foreman, with tape or a patch plan for each hole as the pins are pulled.
No photo
Sheet exposure time within the manufacturer's limit
Days since roll-out compared with the exposure limit in the installation instructions, so a sheet left out through sun and weather isn't buried degraded.
No photo

What usually sends this back

The failures are almost always the evidence, not the work

Laps left loose or short so the seam opens under crews and vibration and the barrier is no longer continuous under the slab.
Pipe and conduit penetrations left with the sheet cut open and no boot or seal, an open hole in the barrier at every stub-up.
The retarder torn during rebar and crew traffic and never patched, so the pour buries an unrepaired hole nobody can reach again.

Common questions

6 answers

What does this under-slab vapor retarder pre-pour checklist cover?: 14 items across 4 sections, covering continuity and laps, penetrations sealed, damage and edge tie-in, reinforcing and pour protection. 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 concrete foreman placing the retarder with the GC's superintendent, at the hold point right before the pour is released.
When in the schedule should this walk happen?: After the retarder is laid, lapped and reinforcing is set, immediately before concrete is placed, the last moment the sheet is visible.
Why do these items ask for a photo?: 9 of the 14 items call for photo evidence, 12 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 an under-slab vapor retarder pre-pour inspection?: Laps left loose or short so the seam opens under crews and vibration and the barrier is no longer continuous under the slab. Pipe and conduit penetrations left with the sheet cut open and no boot or seal, an open hole in the barrier at every stub-up. The retarder torn during rebar and crew traffic and never patched, so the pour buries an unrepaired hole nobody can reach again.
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.

Related checklists

Under-slab vapor retarder Rough-inUnder-slab vapor retarder rough-in inspection checklistSubgrade fine-graded, compacted and clear of sharp debris so the vapor retarder can lie flat without being punctured14 items11 photos Under-slab vapor retarder FinalUnder-slab vapor retarder final inspection checklistAfter the pour, the slab edge and penetrations confirmed intact where the retarder tie-in is still visible or documented12 items5 photos

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