I don't have room for soffits in my attic so it is quite dank and mildly mildew smelling.

I would like to seal off the one eave vent, spray foam directly on the roof deck and remove the batts in the floor, to bring the temp of my attic up to usable space (for storage and a hot water heater)

My home is in northern Alaska, where temperatures are sub zero for months at a time. I just had a brand new metal roof installed, and the self sealing fasteners can be seen poking through the decking (1/4 inch) into the attic. Can I foam directly onto the plywood, or is there a different way?

Greatly appreciate any experiences and/or recommendations.

Thanks.