I own a 70-year-old home with a slate roof which has a very steep pitch. We
also have what I believe are called "knee walls" in several locations on
the 2nd floor. Currently, we have 2 gable vents facing east and west. On the
east one, I have an attic fan which comes on when the temp gets to at least
70. Unfortunately, the fan is much bigger than the vent opening and so does
little to evacuate any air.

I am thinking about soffit vents, but I'm worried about the damn knee walls.
There's no insulation on them and getting back there is impossible without
tearing the wall down. I mainly want to eliminate the ice dams in the winter
and the high attic temps in the summer.

TIA
m