A belt course, also called a string course or sill course, is a continuous row or layer of stones or brick set in a wall. Set in line with window sills, it helps to make the horizontal line of the sills visually more prominent. Set between the floors of a house, it helps to make the separate floors distinguishable from the exterior of the building.
Although the belt course has its origins as a structural component of a building, by the 18th century it was almost purely a decorative element and had no functional purpose. In brick or stone buildings taller than three stories, however, a shelf angle is usually used to transfer the load of the wall to a hidden, interior steel wall. Flashing is used to cover the space exposed by the shelf angle to help limit the intrusion of water. Where flashing is considered aesthetically unpleasing, a belt course is often used.
- Sovinski, Rob W. (1999). Brick in the Landscape: A Practical Guide to Specification and Design. New York: John Wiley. p. 156. ISBN 9780471293583.
- American Face Brick Association (1920). A Manual of Face Brick Construction. Chicago: John H. Black. p. 110.
- Morrison, Hugh (1987). "Early American Architecture: From the First Colonial Settlements to the National Period". New York: Dover Publications. pp. 305–306. ISBN 9780486254920.
- Ballast, David Kent (2009). Architect's Handbook of Construction Detailing. Hoboken, N.J.: John Wiley & Sons. p. 93. ISBN 9780470381915.