For a farmer-carpenter looking to add a wing to a house without doing any complicated roof cutting, the path of least resistance is to build off a gable-end wall, with a new ridgeline parallel to and lower than the existing ridge. Unfortunately, that sharply reduces the natural light available to the upstairs bedroom in that end of the original house. Lowering the new ridge enough to add a full-size window in a normal orientation would help, but would also eat up valuable space in the addition.
The solution: Recycle one of the old gable-end windows by tilting it at a rakish angle and squeezing it into the narrow strip of wall between the old and new rooflines. The result—often termed a Vermont Window—is a common sight in the Green Mountain State. Occasional examples also turn up in adjacent New Hampshire and Maine, but it's a window placement that's rare elsewhere.
And, one might think, rightly so. By any normal standard, a diagonal window a few inches above a roof plane would seem to be a recipe for slow-motion disaster. It's subject to being buried by snow and soaked by rain splashing off the roof. Any moisture that runs off the glass flows naturally to the bottom corner, where it's liable to permeate the sash, trim, and framing.
But surprisingly, none of the half-dozen or so Vermont-based window restoration contractors we spoke with could recall ever having to make extensive repairs to a Vermont Window. Most speculated that the gable-end overhang typical of Vermont vernacular farmhouses—fairly generous in size and seldom more than a foot or so above the window's upper edge—provides enough protection from weather to make up for the design's obvious shortcomings.
"I'd also guess that orientation makes a difference," says Sally Fishburn, a historical-window expert in Danville, Vt. "I bet you'd find that most of those windows are on the side of the house that faces away from the weather." If true, that could be the happy result of good planning on the part of the original builders—or it could simply mean that the badly oriented examples have long since rotted away and been boarded over.