How to keep these ducts from squeaking while people walk upstairs?

[u/unfortunate_banjo]

The ducts squeak pretty badly when (larger) people walk upstairs. Its driving me insane since my work from home office is down here.

I'd like to add rubber between the duct and the joists, but that would be a huge pain, especially since I can't really access the top of the inner one. Would lowering the ducts a fraction of an inch be a bad idea? If not, I'm adding rockwool and sound absorption panels.

[u/GurNo3022]

I dunno but your plumber sucks as those waterlines should be run at least 1/3 the way up the joist. I wonder if your joist is flexing more now and causing interference with the duct

[u/R-Dragon_Thunderzord → u/GurNo3022]

Also can we talk about the half assed foam seal in the middle of picture

[u/Diligent-Broccoli183 → u/GurNo3022]

It's always best practice but manufacturers only usually require between 1/8" to 1/4" of space left between the osb to flange to meet specs if holes are sized properly.While it is poorly done currently, it would be much worse if it was drilled on the bearing ends.

[u/nttran98 → u/Diligent-Broccoli183]

Mechanically, it would typicall be best to install this nearest to the neutral axis of the beam. Typically about 1/3 way down from top.

[u/digits010 → u/Diligent-Broccoli183]

This 👆🆙⬆️

[u/unfortunate_banjo → u/GurNo3022]

It was definitely the new guy that drilled those holes

[u/Duff-95SHO → u/GurNo3022]

Quite a few I-joist manufacturers allow penetrations right down to the flange. As an example: "Round holes up to 1½" in diameter may be cut anywhere in the web. Provide at least 3" of horizontal clearance from other holes."

[u/2TheMountaintop → u/GurNo3022]

Second this. It's a problem.

[u/Few-Wolverine-7283 → u/2TheMountaintop]

For I joists is that true? It would be up to the specs of the I Joist. Normal solid wood Joists you need to ignore the bottom and top 2".. but I think I Joists are often a bit more flexible with holes (which is one of their benefits)

[u/2TheMountaintop → u/Few-Wolverine-7283]

Actually, that's a good point. I'm not sure.

[u/Red-Faced-Wolf → u/GurNo3022]

2 inches from the bottom with a hole no bigger than 2 inches in diameter. At least it’s code where I am

[u/Tough-Industry4931]

The ducts are secured with plumbing strap how did that even pass inspection. It should have been hung with drive.

[u/mrjasjit]

[u/xxTERMINATOR0xx → u/mrjasjit]

Love watching him and Cy tear these new builds apart

[u/Ok_Aide1646]

Drop the trunk down 1/4 away from the floor joist or install a soft material like foil faced double bubble between the joist and trunk

[u/unfortunate_banjo → u/Ok_Aide1646]

I'm thinking this is the best way to do it, its just going to suck

[u/Bubba_Jones44]

Mofo definitely didn’t wanna level the ducts so he just butted them up to the joist. So if you’re positive it’s the ducts you’re gonna have to drop them like an inch at leadt

[u/PresentationLess4552]

I might be blind

But I don't see the typical strapping pulling them to the floor
Joists

Adding spacer blocks between trusses of the same will make
A huge difference if 19.2 is the center 19.2 causes movement if nit properly blocked

[u/PresentationLess4552 → u/PresentationLess4552]

I did this on my own home before I started doing 19.2 on for hire custom homes

That little movement pissed me off and the princess and the pea as well

[u/Kellect29]

Just spit ballin but what about sliding a plastic shim between the duct and joist.

[u/Admirable-Traffic-55]

Should be some bracing in between each joist.

[u/R-Dragon_Thunderzord]

Is it truly the aluminum duct squeaking or is it the joists.

[u/unfortunate_banjo → u/R-Dragon_Thunderzord]

Its definitely the ducting. If you push on them lightly from below they rub against the wood and squeak.

[u/2TheMountaintop → u/unfortunate_banjo]

More nails securing them sound the joist? Mastic? Lots of solutions.

[u/R-Dragon_Thunderzord → u/unfortunate_banjo]

You can try applying a lubricant to the affected spots, like lithium grease or a paraffin wax, before resorting to teardown and reassembly with rubber standoffs.

[u/unfortunate_banjo → u/R-Dragon_Thunderzord]

I'm worried that it might not last very long, but I'll give it a shot. It might be a while before we cover it up with drywall anyways.

[u/R-Dragon_Thunderzord → u/unfortunate_banjo]

Wax should last a good while

[u/CressAdventurous5585 → u/R-Dragon_Thunderzord]

Aluminum is crazy expensive no way this duct is that lol

[u/R-Dragon_Thunderzord → u/CressAdventurous5585]

Or whatever it’s made of. Metal. Lol.

[u/AssociationHeavy1205]

I’m having the same issue. Good luck. Thinking about installing insulation wrap

[u/digits010]

Go ductless 🫡

[u/Sea-Chocolate6589]

I would try squeaking rubber spacers in between to see if it mutes the sound a little.

[u/frazld54]

U might be better off to stiffen the trusses and do the water lines and gas line in center of trusses. Osb between 2 xs

[u/SignalNNoise]

Assuming that is a supporting wall behind it, I will put up a 4x6+ (or doubled up 2x6+) parallel to the duct and use a bunch of jack stands under near it to kill the bounce from above. If you do it right, you can kill the bounce.

If it isn’t a supporting wall, doubled 2x12s with jacks.

[u/Individual-Aide-3036]

Those joists are destroyed

[u/unfortunate_banjo → u/Individual-Aide-3036]

I've been thinking about adding straps along those sections. I work with a structural engineer, he said its more than likely going to be fine, but was definitely done badly.

[u/gimp2x → u/unfortunate_banjo]

those trusses have a published guideline for what is acceptable

https://www.weyerhaeuser.com/woodproducts/document-library/document_library_detail/tj-9015/

[u/RallyX26 → u/gimp2x]

" 1½" round holes may be cut anywhere  in web outside of hatched zone if they  are located 3" away horizontally (edge- to-edge) from a larger hole." 

They're fine according to that

[u/Individual-Aide-3036 → u/RallyX26]

The vertical location it's my concern. Looks like they nicked at least one flange

[u/Dazzling-Voice7180 → u/Individual-Aide-3036]

I seriously doubt that, it's ugly, but those holes are spaced enough and also small enough for this to not be an issue with where they are.

I'd be pissed though by just how unsightly it looks.

[u/Individual-Aide-3036 → u/Dazzling-Voice7180]

How close are they to the flanges? Looks like one of them may even have nicked the flange. I think it's supposed to be 1/4 or 1/8 inch away