I recently removed old plaster that was peeling paint badly. The interior of the wall is wood sheathing 7 inch wide on the diagonal. The sheathing has tar paper between itself and the exterior brick. The top 1 foot of the wall is the exterior soffit. I was planned on using rockwool as the insulation, with a vapor barrier behind the drywall, and spray a waterproof sealer on the brick. My question is that the top of the wall where the soffit is you can see some daylight and i can feel a difference in the temp on the sheathing. I am worried about possible moisture with the temp difference in the soffit area. Is there something else i should be doing to make this be effective. Thanks

Should also add that i live in south carolina

I don't understand why you can't insulate behind the soffit from inside. Why are you spraying the brick?

Paint pealing on plaster usually means a moisture problem....