What is Sill Horn?
Definition of Sill Horn in Construction The extension of the bottom of a window sill to the exterior of the window casing. This is a decorative choice and selection and is common in colonial and authentic classic trim packages. The installation of a sill horn is both time consuming and expensive for the amount of trim involved. The reason for the time and cost is that the sill horn must be milled to allow it to wrap around the casework and terminate at the side of the window trim. In many cases, if there is a need for a sill horn, the actual sill is produced with the side wings that extend to the actual sides of the windows. In this manner the support of the sill horns are not compromised by a joint between the actual window sill and the horn itself.