Divide the inside of a dome into coffers that shrink in step with the meridians as they rise, so that their perspective deepens the dome and draws the eye to the light of the lantern.
Rules · Doors & windows · Light · Ornament
The fanlight
Light the hall over the front door with a fanlight: a half-round light with bars radiating like the ribs of a fan, or, after 1770, an elliptical one, often with narrow lights at the sides of the door.
The hall of a terraced house has no window of its own; the fanlight was its light. The Adam brothers made it finer and elliptical, and the Federal builders of New England added sidelights either side of the door.
Related rules
Make the architrave round a door or window as wide as a sixth part of the opening’s breadth, and dress the openings of the principal floor more richly than those of the storeys above and below, with a frieze and cornice, and on the grandest a pediment.
architrave = ⅙ × width of the light
Break the architrave of a door or window with blocks of plain stone laid across it, alternately larger and smaller, and set a keystone in the middle of the head.
Over a window in a brick front, turn a flat arch of soft red bricks rubbed and cut (gauged) to radiate from a centre below, laid with the finest joints, and give it a keystone of stone where the front is dressed in stone.
Glaze the sash windows in panes of equal size, three across: six over six on the ordinary storeys, six over nine on the tall windows of the principal floor, and three over three in the low windows of the attic.
Carry the front wall up as a parapet in front of the roof instead of eaves of timber (1707); set the window frames back four inches behind the face of the brick (1709), and later hide the sash boxes wholly in the reveals (1774).
Cite this page Chris Paton, “The fanlight”, The Textbook of Architecture, https://textbookofarchitecture.com/rule/fanlight. Text, drawings and models licensed under CC BY-NC 4.0.