Round ductwork sitting on the attic floor - insulation compression

JamesC in Stamford CT

Hello,

Does anyone know a product to put little feet under rigid round ducts in an uninsulated attic? (NY State). The contractor installed the ducts sitting on the attic floorboards. And the R8 fiberglass insulation seems to be being compressed at the bottom by the weight of the duct.

I can find only industrial from-below roof supports online, and seems this should be a common issue and there probably is a simple, less expensive product out there. I think the ducts are 16" and 10", but if that's important I can go measure. See pictures.

Thanks in advance for any help!

Intplm.

If you want. You can look up something called "Black woven duct strap."
It's used to hang that type of duct.
However, that duct is fine just the way it is.

HVACNUT

Looks like flex so there's really not much weight there.

EBEBRATT-Ed

If it was big heavy duct, it would be one thing. Flex duct isn't an issue because it is light. Hang it from overhead

JamesC in Stamford CT

Thanks so much for your replies!

I am not worried about the flex legs. You can see a flex coming off the main trunk int he original photos I posted, but that is not the worry.

My question is about the main trunk lines, In my original post I showed the 10" rigid ducts with insulation on top. They are smaller thant he 16" trunk, but even the 10" ones are quite heavy and compress the insulation. In this new photo, in the foreground, you can see the even heavier 16" duct.

Hanging form the ceiling would be possible, but difficult, the timbers are solid chestnut. I would prefer some little stilts from below, is there a product out there for that?

Thanks!

EBEBRATT-Ed

A duct guy could bend up some Sheetmetal angle and screw it to the duct to hold it up a couple of inches but their is nothing specifically made for this.

EdTheHeaterMan

Is there a condensation problem at the point of the compressed insulation ? Otherwise what is the point?

I have used this product to lift duct off the floor in an attic. After you insulate the ductm then put a nail or screw in the roof rafter above the duct to act as a hook, then you just wrap the wire around the duct and around the hook in the roof and adjust the hight as needed. They are adjustable.


The wire will compress the insulation so you will need to add some 4" wide strips of insulation around the wire to compensate for the compression or some other adjustments can be made.

JamesC in Stamford CT

Thanks very much for the info.

clammy

Usually use duct strap it’s 18 gauge I believe it comes in 10 ft lengths x 1 wide and it’s not drive material . It will be vastly cheaper than cable wire and cl clips . You can make bends and twists w hand seamers and lines men pliers . I use it hang all duct work just because of that . In a pinch you could get 2 inch foam board and place 6 x 20 wide strips ever 4 ft and at least the area getting compressed has a r valve and it lessen the total area of insulation being compressed and it easier .
Peace and good luck clammy