Under/inside roof/ceiling - redo vapor barrier?

[GraceNC]

I've removed the celing, all insulation (what was left of it since the 60s), all wiring, etc.

Am left with rafters and a silver metal underside of roof. The roof isn't peak, nor flat....kinda a dome, slight curve. There are no openings at all - all venting is done through the exterior walls.

What is best? What are the steps? Google has people doing all sorts of ways....

insulation first, electrical wiring, THEN vapor barrier stapled to rafters, put ceiling up? Or do you put something on the metal underside of the roof itself first?

Plus, the 'attic' space isn't but a foot, at best and gets to an inch on the sides at the narrowest points. Do I have to worry about ventalation?

Thanks for your help.

[upstateman]

Do your wiring first,leave a little slack in the wiring so insulation can be tucked up in the roof.My roof isn't vented, but the insulation goes from ceiling level to metal roof level.Remember not to compress the insulation.Run your vapor barrier.It should be tucked behind the wall vapor barrier and sealed with something like tuck tape(not duct/duck tape).If you're doing drywall,use 1x2 perlins ran the length of the mobile home,wall to wall, on 16 inch centers.This will give you more places to screw the dry wall to.It's heavier and will sag,if not fastened properly.I use 16 x 16 inch grid when running screws in.Finish just like any other drywall ceiling.Check with your home improvement store,they can sometimes get sheet rock specific to ceiling applications.It's a bit thinner and lighter but still needs a good fastening grid.

This is a pic of perlins ran to hold a drywall ceiling to the bottom of the truss roof.It's all so known as ceiling strapping.The spray foam insulation negates the need for a vapor barrier.