Give a pointed building a steep roof, the gable close to an equilateral triangle, which throws off rain and snow and completes the vertical character of the design.
pitch ≈ 55–60° (equilateral gable = 60°)
Pugin contrasted the steep, visible roofs of medieval churches with the low roofs of classical buildings hidden behind parapets and balustrades, to him a sign that the classical architect was ashamed of his construction. The steep roof became a badge of the Gothic Revival in England and America, where its pitch was also defended as practical in a wet northern climate.
Raise the central nave above the lean-to roofs of the aisles and pierce the upper walls with a row of windows, the clerestory, so that the middle of a wide hall is lit from high on both sides.
nave height ≈ 1½–2 × nave width; one window over each bay of the arcade
Divide the elevation of the nave into three storeys: a tall arcade opening into the aisles, a low triforium passage in the thickness of the wall against the aisle roof, and a clerestory of large windows reaching up into the vault.
Chartres: arcade ≈ clerestory, triforium a narrow band between
Proportion the cross-section of a church from the square: let the total height to the crown of the nave vault equal the total width, and take the heights of the aisles and the springing of the vaults at whole divisions of that square.
H = W · levels at k × (W ⁄ n)
Alternatively, fit the section to an equilateral triangle standing on the width, so that the height is √3⁄2 of the width, and take the levels at equal divisions of that height.
H = W · √3⁄2 ≈ 0.866 W · Milan: 96 braccia wide → 83.1, rounded to 84 = 6 × 14
Within a generation the nave vaults of the French cathedrals rose from about 37 m to 48 m while their spans stayed near 15 m: the ratio of height to width climbed from about 2.3 to over 3, until at Beauvais part of the choir vault fell.
Chartres ≈ 37 m · Reims ≈ 38 m · Amiens ≈ 42 m · Beauvais ≈ 48 m
Let the principal room of the front stand out in a bay window, canted or square, under its own gable: more light, a view along the street as well as across it, and a front that shows where the best room is.
Cite this page Chris Paton, “The steep roof”, The Textbook of Architecture, https://textbookofarchitecture.com/rule/pugin-steep-roof. Text, drawings and models licensed under CC BY-NC 4.0.