Are you in an area with enforced building codes? If not, and Brian's description of a lattice underlayer is correct, you could avoid the sheathing step and simply put raised panel roofing on top of the lattice.

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1977 300d 70k--sold 08
1985 300TD 185k+
1984 307d 126k--sold 8/03
1985 409d 65k--sold 06
1984 300SD 315k--daughter's car
1979 300SD 122k--sold 2/11
1999 Fuso FG Expedition Camper
1993 GMC Sierra 6.5 TD 4x4
1982 Bluebird Wanderlodge CAT 3208--Sold 2/13

im definitely in an area with enforced building codes, another thing im considering though is insulating while I do this?

Ill explain, so the large space around the central stove was originally a nearly 1.5 story peaked structure with rafters and the peaked roof above. One of the residents installed a drop ceiling for insulation, and above is quite literally a farmer constructed roof steeped in history.

What id like to do is knock out the drop ceiling, and expose the old structure of the building.

I dont want to lose the insulation of the drop ceiling though, so I was wondering if it made sense to remove the existing roof, put down plywood on the lattice, or whatever's there, install 2.4s on the outside of the plywood, and put in insulation, then cover that with plywood, and roof over that.
Right now im just talking out of my *** saying whatever seems reasonable, I have no idea whats acceptable or legal.

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I don't think that will meet code.

__________________
1977 300d 70k--sold 08
1985 300TD 185k+
1984 307d 126k--sold 8/03
1985 409d 65k--sold 06
1984 300SD 315k--daughter's car
1979 300SD 122k--sold 2/11
1999 Fuso FG Expedition Camper
1993 GMC Sierra 6.5 TD 4x4
1982 Bluebird Wanderlodge CAT 3208--Sold 2/13

research time then. Monday inspection will be done, and I can see if im serious

__________________
This post brought to you by Carl's Jr.