[3] They are principally installed in farmhouses from the 19th century,[1][2] and can be found less frequently in new construction.When a house is expanded, for example with a kitchen wing or an attached shed, there may be very little wall space available in the gable end in which to put a window, which may be the only window available for an upper floor room (if there is no dormer—adding a dormer to an existing roof is problematic, as it involves puncturing the roof membrane[9]).[4][10] An alternative explanation for the orientation of the window is that getting at least one corner of a window up as far as possible in the interior of the house allows hot air (which rises to the top of the room) to escape on summer afternoons.[5] However, this reasoning seems suspect, as Vermont is not as hot as many other locations,[11] where the windows are not ubiquitous.One solution is to orient all of the siding on the wall so that it is parallel with the window frame.
On this house, the clapboards are hung at an angle to match the window frame.
A very unusual example of a diagonal window set in a brick wall