Attic insulation over dropdowns

[IamTheWalrus]

A new house will be built, second floor of 2000 sf has hipped roof structure over, all built with engineered trusses, bottom chords of trusses all level.

In the rooms below, there are framed boxdowns to create soffits and to lower the ceilings in some small rooms and hallways. Ceiling height to bottom of trusses is 10', and dropdowns are 14 to 16 inches.

We can slap up sheetrock in all the rooms at truss chord ceilings and do the boxdowns under with steel track and studs, then rock again. This enables the attic insulation, specified as blown-in cellulose, to be drifted in at all the same height. Right up to the fill stick line marks.

If we don't do this, and instead frame the boxdowns all before ceiling rock, we end up with many areas where the attic fill needs to go up and down and fill the fillets. Furthermore, we get some fall-down into wall cavities we don't need.

What do you recommend?

[David Meiland]

Rock and tape the ceiling first, then frame the soffits as add-ons.

[Bill Robinson]

Rock, tape and airseal......

[Ted S.]

I agree, the way to do that is to rock and tape the entire plane of the bottom side of the trusses. Then go back and frame down with light gauge and drywall for the soffit and drop ceilings. A lot of larger multifamily's are done that way

[Dutchman]

I'm not following why it's difficult if the "drop downs" are done during framing.

If they are framed with everything else, then the ceiling is filled, those areas are simply deeper, right?

If I'm missing something, fine. I think this approach helps the rockers because they hate to come back for stuff.

[dlhunter]

I believe if you do the drop downs before drywall you will have to fire stop it anyway so there isn't a direct path from the stud cavities into the ceiling cavities. If you want to frame everything pre drywall just nail plywood to the ceiling where the soffits will be built. Then build your soffits. This way you have fire stop and the insulation will sit on top of the plywood at the same level as the rest of the ceiling. If plywood isn't a suitable fire stop for you grab a few sheets of drywall to give to your framer to use in place of the plywood.

[Dick Seibert]

I was just going to say what Darrel just said.

[Ted S.]

I should note that in the multifamilies I am referring to the metal studs are installed by the same sub who owns the drywall. This first pass of drywall is called "prerock"

The process is probably a bit overkill for house construction.