This past year we overwintered 3 hives and all made it through very well. The year before(our first) we had 2 hives and one made through. We noticed alot of moisture buildup the first year, even though we used homosote boards. I saw some quilt boxes that someone used and thought it was a good idea, so i made 3 of them and put about 3-4 inched of pine shavings in. I think out over wintering success was between making sure we treated for mites, had enough honey, made a candy board, and adding the quilt box. I wrapped the exterior with roofing paper, but wont do it again. Even though it seemed to work ok, I just dont like the stuff. We plan on doing the same configuration next winter, so time will tell if we are on the right track.