Return air ducts in wall cavity

[iowaguest]

I'm remodeling my basement and noticed that the builders decided to use a two 16 x 2 wall cavities for my return air ducts. I'm in a ranch house with 9 ft ceilings. The one duct goes clear to the top of the wall and down to the basement as where the other is in the living room and just a short 3 ft cavity. They both go the basement to the same joist cavity where the "duct" is finished with a 'reflectopan' type thermal cardboard placed across the 16 inch gap between the joists.

Is this considered standard practice? It seems pretty shoddy to me but I wasn't sure if that's SOP for return air ducts.

 

[MintJulep]

It's common.

 

[DRWeig]

Yup, seen 'em in old and new construction.

Good on ya,

Goober Dave

 

[iowaguest]

I'm getting a ton of sound coming down through this cavity, is there something other than the cardboard that I can put in its place that will better block out the sound? Could I do some standard panning and put some 1/2 inch foam insulation along the joists and bottom of the pan?

 

[BM4BRANES]

Consider lining the cavity with this.

http://www.certainteed.com/products/insulation/hvac-mechanical/317382