Walls - sheetrock to siding - what goes where?

[Chuckca]

Ref 20 x 30 loft plan.... (we're adding 6 feet to the length - 20 x 36)  

Can we recap what goes where - maybe discuss some why's - along with some recommendatios:  

Inside to outside -

1/2" Sheetrock or T n' G

Vapor barrier (6 mil)  over 2 x 6 studs (24" oc)

R 19/21 paper backed insulation (paper faces in)

Sheathing (wind barrier)

Form insulation (1" R 7)

Roofing Paper

1 x 3 or 1 x 4 24" oc (siding is nailed to it)

Siding

Seems this was the order....is there any duplication here......

Thanks
Chuck

[John Raabe]

The sheathing is structural and should be nominal 1/2" OSB or plywood.

If you are doing drywall and 1" foam on the outside you may not need the poly vapor barrier on the inside of the wall.

Other than that you have built a good wall with a rain screen and extra insulation.

Adjust this for the appropriate climate as you wouldn't build the same wall everywhere in the US. See "Houses that Work" http://www.buildingscience.com/housesthatwork/default.htm