Static field route #18919

What do I do when drywall or framing crushes a flex duct run?

Flex Duct Connections & Supports🟨 CHECK FIRSTV189 answer-gap expansion

📖 Verified core answer

Crushed flex is an airflow restriction, not a finish-detail inconvenience. Pull it out of the pinch point and use an approved rigid/alternate path that fits the wall cavity without choking the branch.

Open in Field Rescue Open category

Field verification checklist

Confirm where the flex is being pinched and whether drywall/framing is already installed.
Check branch size, diffuser/boot location, and whether rigid wall stack/oval/rectangular duct is specified or approved.
Check for access to replace the crushed section before the wall closes.
Look for excess flex length, tight bends, and strap/crush damage.
Take a photo of the pinch and ask before changing material or route.

Ask foreman

The flex branch at [location] is being crushed by framing/drywall. I checked the boot and wall cavity. Do you want a rigid wall-stack/oval replacement, a reroute, or a different boot location before they close it?

Text to foreman

Route options

AMake the field correction only if it is within your assignment and the approved method.

BHold and document the condition if the fix affects airflow, access, life safety, pressure class, rated assemblies, equipment, or another trade.

CBring the foreman/detailer the location, what you checked, and what decision you need before cover, startup, or rework.

Do not do this

Do not leave flex flattened in a wall cavity because it is hidden.

Why this matters

Crushed flex can create low airflow, noise, comfort complaints, and ugly rework after drywall is finished.

Verification basis

Approved drawings/specs, project coordination drawings, manufacturer instructions/submittals, shop standards, foreman/detailer direction, employer policy, and AHJ/code requirements.