belliott
(Bob Elliott, 450.0002662)
2
Must admit {D} gave me a laugh.
Can be supported by ceiling joists if the support is at least every 4 feet.
I get it though as you are thinking parallel and in them between no doubt.
gromicko
(Nick Gromicko, CMI)
3
Maybe timber framing could have joists 4’ apart. I can’t think of any other scenario offhand.
cbottger
(Charley L. Bottger)
4
You left out the most important item of all (how to properly attache a flex duct to a ridge connector or sleeve)
