Apprentice answer

What is the proper overlap for duct wrap (blanket insulation) on commercial jobs

1st YearInsulation, Liner & CondensationCheck first

Duct wrap insulation should have a minimum of a 2-inch facing lap at all longitudinal and transverse seams to guarantee a continuous vapor barrier seal.

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Plain-English answer

Duct wrap insulation should have a minimum of a 2-inch facing lap at all longitudinal and transverse seams to guarantee a continuous vapor barrier seal.

Field checklist

Duct wrap insulation should have a minimum of a 2-inch facing lap at all longitudinal and transverse seams to guarantee a continuous vapor barrier seal.

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Hey boss, I’m checking sealing & insulation: What is the proper overlap for duct wrap (blanket insulation) on commercial jobs? I found the likely issue and want to verify the next step before I lock it in. Do you want me to adjust it now or check the drawing/detail first?

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Use this as training guidance. The foreman, approved drawings, project specs, manufacturer installation instructions, employer safety policy, and AHJ/code requirements always control the final answer.

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