Window sills can add character to the look and feel of a space. follow scott through the steps of building custom window sills to see how a window sill is designed and installed.. Left: detail of the stool and casing on the left side of the window. the casing was also ripped to width on a table saw to accommodate for the wall and yet expose a reveal around the window jamb extensions. right: the apron and casing on the right side of the window. the horn is clearly visible.. With the side casings and stool in place, the next step is to install the apron under the stool. start by cutting a 45-degree miter on each end. mark for the long point of the miters by resting the apron on the stool and making marks where the outside edges of the casings intersect the apron material..
Remove window stool: if the existing window stool doesn�t extend past the drywall on each side by the width of the new wood casing plus 1/2�, remove it and the apron molding under it by cutting through the caulking with a utility knife, then using a pry bar and hammer to take it out.. This makes the miter on returned stools go through the casing corner and suddenly it looks like it was a "plan". i use the same reveals on routed ends because i find it balanced and pleasing to the eye. the reveals themselves need to be determined by the size of the moldings and overall look of the window trim.. Whether restoring old houses or building new ones that look old, tom silva finds finish carpentry the most satisfying part of the job. for this project, tom installed window trim that has reeded side and head casings, plain corner blocks, a thick stool, and a dainty apron, all of which he copied from the original trim..
