Many builders and designers shy away from roof designs that use halfhigh, second-story walls, because they are worried about the structural problems. Actually solving those problems is not very difficult, and worth the effort, since story-and-ahalf houses have so many design advantages. Outside, such a building looks like a tall, elegant, one-story house, while inside, for all practical purposes, it has two full stories. Assuming the half-high wall is 4 feet and the roof is pitched at 12/12, there is room for closets or stairs under the eaves, and dormers rise gracefully along the plane of the outside walls. The second story costs less than in a full two-story design, and its slanted ceilings add an interesting architectural detail. The design's classic