Reglet

A reglet is found on the exterior of a building along a masonry wall, chimney or parapet that meets the roof.

It is a groove cut within a mortar joint that receives counter-flashing meant to cover surface flashing used to deflect water infiltration.

[1] The counter-flashing is then inserted to the reglet and held in place with thin metal wedge covered with a sealant.

[3] It is easily removable for roof repair and flashing replacements.

A face reglet can also be called a raggle[4] and may be related to regle, a groove.