After unprecedented ice storms, I have an ice rink on a portion of my roof. Solid ice at least 2-3 inches thick. I also have some icicles coming out of one vent on my eaves, which seems like pretty good evidence that water is getting into the attic. The ground is also covered with 3-4" of solid ice, making a ladder ascent impossible. I tried putting some ice melt in a stocking but it just slid off the roof.
I have never had this problem before, so I hope it’s not insufficient insulation in my attic. It only happened on the part of the roof that is always in shade; other parts of the roof that get more sun don’t have any ice buildup.
How much insulation should I have in the attic? There is insulation blown in up there maybe 3-4" deep. I was thinking of putting a thermometer in the attic to see if it is getting too warm. What should the temperature difference between the house/attic/outside be? How much would it cost to get more insulation blown into a two-story, 2000 square foot house?