Cutting through liner/vapor barrier incorrectly

Verify before making a permanent change: cutting through liner/vapor barrier incorrectly.

High-risk starter answer - stop before cutting, drilling, coring, sleeving, enlarging, patching, or relocating any opening. Verify the latest approved layout, structure, utilities, rated assembly, sleeve/firestop/waterproofing detail, and foreman/GC approval first.

Stop if

• Ask when the cut affects structure, roof, rated wall, damper/access, grease/industrial duct, equipment, or another trade.

Watch out

• Do not cut because the duct does not fit.

Check

• Confirm the exact location from approved drawings and field marks.
• Check what is above, below, behind, or inside the cut.
• Verify whether the wall/deck/roof/shaft/beam is structural, rated, waterproofed, post-tensioned, or shared with other trades.

Steps

• Confirm what you are cutting/drilling/fabricating.
• Check latest drawing/shop detail.
• Look for hidden utilities, structure, rated assemblies, roof membrane, or equipment parts.
• Focus on the actual issue: cutting through liner/vapor barrier incorrectly.
• Photograph or mark the condition if someone else needs to approve it.

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