Short answer: snagging a ductwork installation properly means walking it while it's still accessible and checking sealed ends, damper access, intact insulation, secure supports, correct labelling, and as-built accuracy against what's actually on the wall. Snag it after ceilings close and half of that list becomes a demolition exercise instead of a checklist item.
What to actually check, and what happens if you don't
Duct ends are sealed. An open or poorly sealed duct end doesn't announce itself — it just quietly leaks air, undermines the system's designed performance, and in some cases lets contaminants into a supply run before anyone's aware there's a problem.
Damper access is confirmed, not assumed. A fire or volume control damper that's technically installed but boxed in by a final ceiling grid, or positioned behind an access panel that doesn't actually align with it, is a damper nobody can service without cutting into a finished ceiling. This is worth checking with the panel in place, not just against the drawing.
Insulation and lagging are complete and undamaged. Gaps in insulation, or lagging compressed and torn during other trades' access through the same void, create cold spots that can lead to condensation — and on any run with a hygiene or cleanliness requirement, damaged lagging is a finding waiting to happen at commissioning.
Supports and hangers are secure. A support that's adequate on day one but wasn't torqued correctly, or was left resting rather than fixed while other trades needed temporary clearance, fails months later, quietly, as vibration or thermal movement works it loose.
Labelling and identification are present. Unlabelled ductwork is a system that only the original installer understands, turning a routine future repair into guesswork with a damper wrench.
As-built accuracy is spot-checked against the drawing. Not every deviation needs a formal as-built revision, but every material deviation — a re-route, a size change, a repositioned diffuser — should at least be checked and recorded.
Common mistakes
Snagging after ceilings close, when sealed ends, supports and lagging are no longer inspectable without opening something back up. Checking damper positions against the drawing only, not against the access panel actually installed around them. Treating a snag list as complete once items are raised, without confirming each one was actually resolved and re-checked. Skipping the as-built comparison because the workmanship checks alone felt like "enough."
What Cliventa needs
To run a meaningful pre-handover snagging walk rather than a superficial one, Cliventa needs the current drawings, the specification (including any cleanliness or fire-rating requirements affecting insulation and damper checks), and the proposed handover date so the walk happens with enough access still available to catch what matters.
Preparing the full handover pack? See our ventilation handover checklist for what should follow a clean snagging walk.