One room suddenly weak? A disconnected duct run is a common cause.

Air Duct Cleaning Dulles, Virginia
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Ductwork repair · Dulles and Loudoun County

Ductwork Repair for Holes, Cuts and Loose Connections

Ducts get stepped on in attics, torn by pests in crawl spaces and knocked loose when other trades work nearby. Most of that damage is repairable. The fix depends on the duct type, and every good repair ends the same way: a fastened, sealed, supported and insulated run.

Quick answer

Yes, most damaged ductwork is repairable. Holes in metal ducts take a sheet metal patch sealed with mastic or metal tape. Cut or torn flex duct gets spliced with a metal connector or replaced. Crushed flex with a torn liner gets replaced and re-supported. ENERGY STAR notes that most heating and cooling contractors also repair ductwork, and it warns against duct tape.

  • PatchHoles in sheet metal ducts
  • SpliceCut flex duct, over a metal connector
  • ReplaceCrushed flex with a torn liner
Ductwork repair decision pathFour steps: find the damage, match the fix to the duct type, fasten and seal the joint, then support and insulate the run.1. Find the damageinspection, camera or a weak room2. Match the fix to the ductpatch metal; splice or replace flex3. Fasten and sealscrews or clamps, then mastic or metal tape4. Support and insulatestraps, no sags, insulation rejoined
Original diagram based on ENERGY STAR duct sealing guidance.

Match the Damage to the Repair

Common ductwork damage and the usual fix
DamageUsual repairReplace instead when
Small hole in sheet metalMetal patch, screwed and sealedRust or damage runs along the section
Joint pulled apartRefit, fasten with screws or a clamp, sealThe fitting is bent or crushed
Cut or torn flex ductSplice over a metal connectorSeveral tears along the run
Crushed or kinked flexStraighten and re-supportThe inner liner is torn or flattened
Sagging flexAdd support straps—
Wet or moldy duct insulation—Always; the EPA says it can't be cleaned effectively

Can't find the problem? A camera inspection tracks it down.

Fixing a Hole in Metal Ductwork

  1. Turn the System Off

    No airflow means no dust blowing out while you work.

  2. Clean Around the Hole

    Wipe away dust and oil so the sealant bonds.

  3. Cut a Sheet Metal Patch

    Make it large enough to overlap the hole on every side.

  4. Screw the Patch in Place

    Short sheet metal screws hold it tight to the duct.

  5. Seal the Edges

    Cover every edge with mastic or metal tape.

Splicing a Cut Flex Duct

Flex duct has three layers: an inner liner that carries the air, a blanket of insulation and an outer jacket. A proper splice rejoins all three.

  1. Pull Back the Jacket and Insulation

    Expose a few inches of liner on both cut ends.

  2. Join the Liners Over a Metal Connector

    Slide both liner ends over a metal sleeve and cinch each with a tie strap.

  3. Seal the Liner Joints

    Mastic or metal tape goes over both joints.

  4. Rejoin Insulation and Jacket

    Pull both layers over the splice and tape the jacket closed.

  5. Support the Run

    Straps keep the splice from sagging or pulling apart again.

Why Duct Tape Fails on Ducts

ENERGY STAR tells homeowners never to use duct tape on ducts because it isn't long-lasting. Virginia's residential code requires ducts, air handlers and filter boxes to be sealed, and a repair wrapped in peeling tape leaks again. Use mastic or metal tape, as covered on the duct sealing page.

What Sets the Repair Price

  • Where the duct sits: open basement, attic, crawl space or inside a finished ceiling
  • Duct type: sheet metal, duct board or flex
  • How many joints or feet of duct need work
  • Whether wet insulation or crushed sections need replacing
  • Whether a leakage retest follows the repair

Crawl space runs bring moisture and pest damage into the mix; see crawl space ductwork.

Ductwork Repair FAQs

Can ductwork be repaired?

Yes, most of it. Holes in sheet metal take a patch, loose joints get refastened and sealed, and cut flex duct gets spliced over a metal connector. Replace instead when flex duct has a torn or flattened liner, several tears, or wet insulation, which the EPA says can't be cleaned effectively.

How much does it cost to fix ductwork?

Repair prices depend on access, duct type, the amount of damage and whether insulation needs replacing, so contractors quote after seeing the ducts. A standalone camera inspection near Dulles typically costs $75 to $125 and shows exactly what needs fixing before you commit.

How do you fix a hole in ductwork?

Turn the system off, wipe the area clean, cut a sheet metal patch that overlaps the hole on every side, screw it in place and seal all edges with mastic or metal tape. Skip cloth duct tape; ENERGY STAR says it isn't long-lasting.

How do you repair a cut flex duct?

Pull back the outer jacket and insulation, slide both inner liner ends over a metal connector sleeve and cinch each with a tie strap. Seal both joints with mastic or metal tape, pull the insulation and jacket back over the splice, tape the jacket closed and support the run with straps.

Fix the Run, Then Seal It Right

A repair isn't finished until the joint is fastened, sealed, supported and insulated.

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