A cloverleaf arch is an arch built up from three circular segments, positioned so that the centres of the circles form an equilateral triangle and the segments meet to produce a clover leaf figure. It is also called a trefoil arch or three-lobed arch: two lobes at the sides and one at the top. The Dutch term is klaverbladboog.
The form belongs to medieval building — Romanesque and above all Gothic — and also appears widely in Moorish and Gothic Revival architecture.
Related forms
| Form | Feature |
|---|---|
| Cloverleaf / trefoil arch | Three lobes, rounded head |
| Pointed trefoil arch | Three lobes, rising to a point |
| Multifoil arch | Four, five or more lobes (quatrefoil, cinquefoil) |
Where it is used
- Window tracery — one of the basic figures from which Gothic tracery is composed
- Niches and doorways — as the head over a niche, a door or a statue recess
- Blind niches in facades — decorative in masonry, with no opening behind
- Balustrades and furniture — as a pierced motif in stone or carved timber
- Gothic Revival — nineteenth-century churches and schools use the motif freely
Setting out and structure
The shape can be drawn exactly with compasses: set out an equilateral triangle, use the corners as centres and strike three equal arcs that touch one another. The radius is half the side of the triangle.
Structurally a cloverleaf arch is not an efficient load-bearing shape: the re-entrant points between the lobes are weak spots where stress concentrates. It is therefore usually a decorative infill inside a load-bearing relieving arch or lintel, not the structure itself. In restoration those re-entrant corners are exactly where cracking and spalling turn up.
Related terms
- Trefoil arch
- Trefoil
- Arch
- Tracery
- Gothic architecture
- Gothic Revival
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