Monk and Nun

Style of roof tiling using arched tiles in both layers

Monk and Nun, also known as Pan and Cover, Mission tile, or Barrel tile, is a semi-cylindrical roof tile similar to imbrex and tegula, but instead of alternating rows of flat tiles (tegulae) and arched tiles (imbrices), both rows consist of the arched tile. The top row with the convex side facing up are the monk tiles while the bottom row with the convex side facing down are the nun tiles. Mortar is often used under the monk tile to firmly attach it to the nun tile, though this can lead to failure in areas with cold winters.

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