Vertical concentric vent kit install questions

[iowa27]

OK, I've been doing quite a bit of research, browsing the web, etc. and trying to find good illustrations of how to install a vertically vented concentric system.
It seems all the diagrams I see show installs going through the roof only, not through a ceiling and then on up through the roof.

In my case, I have a sheetrocked ceiling and then on up through the roof.
Can the concentric box be installed to the sheetrock on the ceiling? If so, does the top side of sheetrock need a metal barrier?
Or. does the sheetrock need to be cut away? When going up through the attic area with B-vent pipe, can insulation be up against the pipe, or do I need another barrier.

I know, lots of questions and I appreciate any and all input.
I like to DIY and am able-bodied and don't really want to hire this project out if I can do it on my own.

 

[The Cobbler]

the sheetrock ceiling will need a fire stop spacer , and the drywall gets cut away.
fiberglass or roxul can be against the bvent . not sure about cellulose or spray .Unless of course the specs in the install manual say something different .

 

[Jackfre]

Ok, what type of appliance is your concentric vent actually venting? Cobbler offers b-vent information, but I would not call b-vent a “concentric vent.” CV is in my experience a double wall system with outdoor air coming in the outside pipe and the exhaust gases venting out in the interior pipe, so a sealed direct vent system. You will get advise all over the place without some detail.

 

[The Cobbler]

^^^ good points, thanks for noticing

 

[iowa27]

Thanks for the replies.
I'm installing a Modine separated combustion heater (LP).
So I will need to cut out the sheetrock to allow the box to be installed. Not sure what you mean by firewall spacer.
Thanks again.

 

[Jackfre]

A quick look at Modine’s site shows the available components and the orientation of those items for both sidewall and thru the roof installs. I don’t know if their pipe is proprietary or manuf by one of the big vent manuf.

 

[abdunbar19]

Looks like this died before the question got answered. I am doing the same installation. Modine's manual says category 3 for horizontal and b vent for vertical. Sterling manual says category 3 for either one. The issue seems to be corrosion rather than fire but they don't say.
I am also going through a ceiling and then 44 inches of uninsulated attic and then the roof.

The Modine Concentric vent adaptor box will be attached to the ceiling from below and screwed into blocking from above. The adaptor box will support a single wall six inch round duct that will run from the top of the box, through the attic and through a 12/12 pitch flashing, on the roof, then up to above the snow line. In my case, about 7 feet. This will leave create in effect a large "thimble." A 10 foot length of 4 inch b vent will run through the vent adaptor box and up the six inch duct. It will need to be supported from below and will need to have a drip tee with a cap. They do not say how the drip tee is used but if there is significant condensation it could be monitored, A tap could be installed but if in fact there is significant condensation, I will replace the b vent with category 3 stainless.