Lintel

Rules that use the word

Make every opening a trapezoid. Give doors, windows and niches sides that lean inward, so that each opening is narrower at the top than at the bottom, and span it with a single stone lintel.

A stone lintel’s span is limited by its tension. A beam is squeezed along its top and stretched along its bottom; stone resists squeezing well but stretching badly, so a stone lintel must be deep in proportion to its span and cannot be long. Doubling the span quadruples the stress from its own weight.

A lintel carries only a triangle of the wall above it. In a bonded masonry wall the courses above an opening corbel over it of their own accord, so the lintel carries roughly the triangle of wall with sides rising at 60° from its ends; everything above that triangle arches onto the jambs.

Joints of carpentry worked in stone. At Stonehenge each lintel is pegged to its uprights by a mortise-and-tenon joint and locked to its neighbours by tongue-and-groove joints, and each is curved to follow the circle: the joints of a timber frame reproduced in dressed sarsen.

Relieve the lintel with a triangle. Over a large lintel leave a triangular opening by corbelling the courses on either side, so that the wall’s weight passes to the jambs; close the triangle with a thin slab.

Relieve a lintel with an arch. Over a doorway or window spanned by a lintel, turn an arch in the wall above so that the weight of the masonry is carried round the opening onto the jambs, leaving the lintel to carry only the small triangle of wall beneath the arch.

Where it appears in the book

In the chapters What Is Architecture?, Post and Lintel, Walls and Openings, The Arch, Frame and Skin, The Ancient World, The Americas.

A feature of Prehistoric and Megalithic, Aegean Bronze Age, Andean, Ancient Egyptian, Ancient Greek architecture.

Nearby in the glossary

Leak window · Lesene · Lierne · Light · Living hall · Loggia · Lombard band · Long gallery