At one time, dormers were added to attics to let in a little light. These dormers were rarely wider than four feet, and such small cutouts rarely broke up the integrity of a roof. But over the years, dormers became an element of style and grew. And grew. Now it is common for a dustpan dormer to be nearly as wide as the roof, with lots of nice windows and no collar ties so that the owners can make better use of the space. Big dormers are wonderful for transforming a small Cape into a moderate-sized house. But when the snow comes, they often are structural disasters. The rafters over a dormer are at