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Apprentice Q&A · #306

Is one sheet metal screw enough to hold a duct hanger strap?

1st YearStrap Hangers / FastenersRED · Stop and get direction

One small screw into duct skin is not a safe hanger attachment. Stop loading it and refasten by the approved hanger/support detail.

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Answer

A hanger strap attached with one short screw can tear out, strip, or unzip the sheet metal under load.

Support the run, check all similar straps, and refasten using the approved quantity/type of fasteners, backing, washers, bolts, or structural support method for that duct and load.

Field checks

Ask foreman

This hanger strap at [location] is held by one small screw into duct skin. I stopped loading it. Do you want the straps refastened per approved support detail across this run?

Text this

Do not do this

Do not trust one short zip screw as the structural support for a duct run.

Why this matters

A weak strap attachment can tear loose and drop or distort overhead ductwork.

Final direction still comes from approved drawings, specs, manufacturer instructions, employer policy, foreman/detailer direction, structural/seismic details, and AHJ/code requirements.