A high-performance masonry architectural detail requires specific components working together:
Not all stone is created equal for sills. stone window sill detail
The sill should project slightly beyond the face of the wall. This creates a shadow line for aesthetic depth and ensures water drips clear of the wall cladding. A typical overhang is 1 to 2 inches, though this varies by architectural style. but weight should always be calculated.
Heavy stone sills need to be secured. Typically, this involves non-corrosive metal anchors or dowels set into the masonry below. For lighter sills, a high-quality construction adhesive and mechanical fasteners may suffice, but weight should always be calculated. stone window sill detail