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Apprentice Q&A · #289

Why did the drop-in anchor blow out in a fluted pan deck?

2nd YearAnchors / Deck AttachmentsYELLOW · Check First

A blown-out pan-deck hole means the anchor no longer has reliable bite. Stop using that hole and switch to the approved deck attachment for that substrate.

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Answer

Drop-in anchors need solid material around them. If lightweight concrete or a fluted pan-deck valley breaks out, the hole is no longer a trustworthy hanger point.

Confirm the deck type and approved attachment. The recovery may be a different location, approved deck screw, top-of-flute attachment, beam/joist clamp, or engineered support detail.

Field checks

Ask foreman

The pan-deck hole at [location] blew out and will not hold the anchor. I checked the deck profile. Do you want an approved deck screw/top-of-flute attachment or a new support location?

Text this

Do not do this

Do not pack an oversized blown-out hole with random sealant, washers, or hope.

Why this matters

A bad deck attachment can let the hanger slip after the duct is loaded, pressurized, or vibrated.

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