How to fix sagging rectangular duct work?

[knucks]

Not in my garage, but in my crawl space, I have HVAC ducts whose clamps are broken/coming off, and my ducts are sagging. What is the best way to repair?

I don't see how I could get into the space between the wood jousts and the top of the air ducts to bend new galvanized strips in the same shape..

Any tips or tricks? Additionally what do I need to be able to squeeze a long drill bit or similar between parallel ducts? I have some clamps broken in between two ducts..

 

[Kobuck]

Screw an L shaped bracket to the old hanger then into the joist to pull it back up.

 

[larry4406]

Remove those nails. Bend the "flange" 180 degrees the other way. Now you can easily nail or screw them to the joist since the tail of the flange is no longer above the duct.

 

[Kenstone1]

Remove those nails. Bend the "flange" 180 degrees the other way. Now you can easily nail or screw them to the joist since the tail of the flange is no longer above the duct.

this^
and use screws not nails
You could cut the nails flush to the floor joist with a saw-all or a Oscillating Multi-Tool, way easier than trying to pull those nails.
jmo,
.

 

[D45]

Remove those nails. Bend the "flange" 180 degrees the other way. Now you can easily nail or screw them to the joist since the tail of the flange is no longer above the duct.

Simple and great idea........time to fix mine now, haha

 

[The Cobbler]

also it's easy to unscrew the bottom tab , pull the hanger cleat away from the duct, run a screw into the joist, button it back up .

 

[Innovate1]

For the tight spaces between the ducts it may be easier to just add another bracket. Then use a long extension for driving screws into the new bracket. Metal pipe strapping (think that's what it's called - the strip with holes you can get in a roll) could be used and is readily available. Screw it to the bottom of the duct or run it all the way under and screw it to the joist on the other side.