My kitchen had paneling along the outside. wall with a 1'x1' box over the sink. I guess you would call that an eave. I skim coated and taped the corners. I taped some of the seems other's I did not. It looked great for about 8 months until this winter and then started to crack along all the joints. I know what needs to be done. Screw in the corner and tape the joints. But I suspect that it is really cold behind the eave. Would vents help keep the heat a constant and reduce cracking.