How to Trim Out a Window
Tom Silva's step-by-step instructions for one of his favorite jobs—installing window casings
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 shows you how to install 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. "People often put in a casing that's too small or a different style," Tom says, "but I think it adds to the feel and the value of a home to keep to its original character."
As with all finish carpentry, Tom says, successful installation begins with stable material - clear, kiln-dried wood or precast foam - and ends with precise measurements and cuts. The result is a seamless assembly with tight joints and no gaps between wall and casing. "Take your time, and always measure twice before you cut," says Tom.
Trimming Out a Window
When installing window casing in old houses, Tom often has to contend with walls that dip and bulge, causing gaps between the trim and wall. He can't ignore these imperfections, but he doesn't fill them with caulk. Instead, Tom uses wood filler strips. "I like to leave a nice clean edge for the painter," he says.
To make them, he first rips a scrap piece of casing to a width of 1 inch and as long as the casing is high. He sets the legs of a compass to span the largest wall-to-casing gap (as shown in "Fill in the Gap" 1, far left). He then transfers that distance to the face of the scrap wood (as shown in "Fill in the Gap" 2). Next, he places the strip perpendicular to the casing at its outside edge, resets the compass to the distance between the largest gap and the mark on the scrap, and scribes the profile of the wall onto the scrap piece (as shown in "Fill in the Gap" 3). After cutting along that line with a jigsaw, he applies carpenter's glue to the profiled scrap piece and slides it into the gap so wall and trim marry perfectly (as shown in "Fill in the Gap" 4). "With a light sanding and paint, the joint disappears," Tom says.