Monk and nun tiles are a matched pair of half-round roof tiles: the nun is the wider under-tile laid with its hollow side facing up, and the monk is the narrower over-tile laid convex side up, covering the joints between them. Together they form one of Europe’s oldest roof coverings, descended directly from the Roman tegula and imbrex.
The names refer to the silhouettes: the broad, plain nun with the curved hood of the monk over it.
How the covering works
The nuns are laid side by side on the battens, forming shallow troughs that carry water down the slope. The monk sits over the abutting edges of two adjacent nuns and covers the joint between them. Water falling on the monk runs off left and right into the nuns. The result is the strongly ribbed roofscape that is recognisable from a distance.
Both tiles have a nib at the head with which they hook over the batten. They are left unglazed or glazed, and the classic terracotta colour is characteristic of the Mediterranean.
Points to watch
- Roof pitch. The required pitch differs greatly by country and by product. In Germany the standard pitch for this covering is around 40 degrees, with a lower limit of about 34 degrees provided a weathertight sub-roof is present. In Italy, Spain, France and Portugal comparable half-round tiles are laid on far shallower pitches, in the order of 20 degrees. Always follow the manufacturer’s figure for the tile chosen
- Sub-roof. At shallow pitches, and wherever there are habitable rooms below, a weathertight but vapour-permeable sub-roof is necessary. The covering itself is not proof against driving rain or wind-blown snow
- Headlap. The tiles lap each other along the slope; a figure in the order of 80 mm is typical, but the product data sheet governs
- Weight. A monk-and-nun roof is heavy, because two layers of tile lie on top of one another. When replacing a lighter covering, the roof structure must be checked
- Fixing. On steep roofs and in exposed locations the tiles are mechanically fixed or bedded in mortar. Simply laying them on the battens is not enough in a north-west European climate
- Listed buildings. Changing the covering of a listed building requires consent
Related terms
- Roof tile
- Pantile
- Tiling batten
- Counter batten
- Roof pitch
- Sub-roof
- Listed building
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