我们在明尼阿波里斯，有一栋1923年都铎式的房子。去年是我们在这所房子里的第一个冬天。我们去年遭遇了严重的冰灾，而且有大量证据表明，过去也曾出现过问题。二楼是一个完整的楼层，由一个小屋屋顶加建，没有通风，我可以看到。由于没有窗户，剩余的/原来的屋顶有最小的通风。这里只有花盆，但没有通风管。该楼层的一半是可进入的无条件阁楼，与生活空间在同一层。通过全尺寸门进入。有一堵高墙将两个空间隔开。沿着屋脊有一个狭长的阁楼空间，那里也有几个通风口。 The bath and one bedroom have a 45 degree wall/ceiling (against the roof) between the accessible attic and inaccessible attic below the ridge. Before we purchased the home an AC unit (air handler and condenser) was placed/retrofit in the unconditioned space. There is a mess of fiber glass in the attic against the knee wall and blown in cellulose on the floor. I believe this is the cause of most of my issues. My question: can I condition the attic and convert it to an unvented roof with closed cell foam, while leaving the adjacent living space original? Is mixing vented and unvented a bad idea? The only way to access the whole roof would be to remove some of the sheathing, but I would like to avoid that if possible. Thanks in advance. Joe.