Vapor Barrier Verification Checklist PDF

Full QC Checklist+

Verify area setup, mil thickness and overlap, roll/tape/fastener quantities, and cost before ordering materials.

✓21 Inspection Points

✓4 Verification Categories

✓Area Setup+

Every area was measured on site, not assumed from a plan — crawl space, under-slab, and wall/ceiling poly each got their own row.
Area Type matches the actual installation (ground cover vs. under-slab vs. wall/ceiling) — mil thickness and overlap defaults differ by type.
Length and Width were entered as the dimension the roll spans across (Width) vs. the course run direction (Length), not swapped.
"Identical Areas" count reflects how many separate areas of this exact size exist, not the total area count in the whole project.
Crawl space clearance (height to joists/girders) was confirmed sufficient for safe installation access before ordering materials.

✓Mil Thickness & Overlap+

Mil thickness meets or exceeds the applicable code minimum for this area type (6 mil crawl space per IRC R408.3, 10 mil under-slab per the 2021 IRC) or the project specification if it requires more.
Overlap entered matches the actual project specification, not just the calculator's code-minimum default — some jurisdictions or specs require more than the minimum.
Roll Width selected matches what is actually available from the supplier, not just the calculator's default.
Seams are planned to overlap onto the course laid FIRST, not the reverse, so water or vapor sheds toward the lower sheet rather than finding a lip to catch on.

✓Rolls, Tape & Fasteners+

Poly Rolls figure is understood as grouped per mil-thickness/roll-width combination — different mils never pool onto the same roll count.
Seam Tape and Perimeter/Foundation Tape figures were cross-checked against the actual number of seams and perimeter length before ordering.
Sheeting surface was cleaned of dust and debris before taping seams — tape adhesion failure on a dusty liner is a common, preventable cause of a seam opening up later.
For crawl space work, Termination Bar is turned on if the project specifies mechanical fastening at the stem wall, not left at the default.
For wall/ceiling poly, Framing Spacing matches the actual stud/joist spacing, not left at a guessed default.
Waste / Turn-Up Allowance % was increased above the 10% default for a crawl space with many piers, posts, or ductwork runs.

✓Installation Quality & Final Check+

Any sheeting punctured by foot traffic, aggregate, or reinforcement during installation was patched with tape before it is covered by fill, rebar, or a pour.
For an under-slab barrier, sheeting was inspected and any damage repaired AFTER rebar/mesh placement but BEFORE the pour, when it is still accessible.
For a crawl space, the ventilation or dehumidifier plan matches whether the space is designed as vented or unvented — ground cover alone does not make that determination.
Cost estimate is understood as poly sheeting, tape, and fasteners only — cavity insulation and drywall are priced separately via their own calculators.
Currency and unit cost entries reflect current local supplier pricing, not a placeholder default.
Mil thickness and overlap used in this calculator match (or exceed) the local building code and project specification before ordering.

Inspection Notes+

Use the latest approved drawings, specifications, and site measurements.

Complete all critical checks before proceeding to the next work stage.

Record deviations and confirm rectification where required.

Inspection Notes

Use the latest approved drawings, specifications, and site measurements.

Complete all critical checks before proceeding to the next work stage.

Record deviations and confirm rectification where required.

Use it after collecting the project inputs and again before approving or closing the relevant work stage.

No. It supports verification but does not replace approved drawings, specifications, codes, manufacturer requirements, or professional inspection.