An oeil-de-boeuf is a small round or oval window, known in English as a bull’s-eye window. It is used above all in roof slopes, small dormers, gables and over doors, where a rectangular window would not fit or would look too dominant.
Where the form comes from
The French term means literally “ox eye”. The shape became popular in French Baroque and Neoclassical architecture of the seventeenth and eighteenth centuries, where the round or oval window served as an accent in mansard roofs and attic storeys. Across northern Europe you find them in the gables and roofs of country houses and town houses.
Uses
- In a roof slope or dormer — a small round window with its own little hood above it
- In a gable — as a light and ventilation opening for the loft
- Above an entrance — as a round or oval fanlight
- In a blind wall — sometimes as a recessed panel without glass, purely as facade decoration
Oeil-de-boeuf, oculus or rose window?
All three are circular openings; the difference lies in scale and context:
| Term | Characteristic |
|---|---|
| Oeil-de-boeuf | Small, round or oval, usually high in a roof or gable |
| Oculus | Round, also at large scale; also the opening at a dome crown |
| Rose window | Large Gothic circular window with stone tracery |
Practical points
- Weathering into the roof slope — a round roof window needs a fully closing flashing or a purpose-made soaker kit; this is the most common leak point
- Bespoke frame — round and oval frames are always made to order. Expect a considerably higher price than a rectangular window of the same glazed area
- Ventilation — many bull’s-eye windows are fixed lights; if you want to open them, specify a hinged or pivot sash deliberately
- Consent — on a listed building or in a conservation area, adding or altering a roof window almost always needs permission; check with the local authority first
Related terms
- Oculus
- Roof window
- Dormer
- Rose window
- Fanlight
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