In most cases that consists of a stool and apron (what is often called a windowsill and the horizontal trim below it), and head and side casings. in a picture-frame style trim, a piece of casing replaces the stool and apron.. Cut side casings to length: measure from the window stool to the top of the top casing to find the length of each side casing. miter the top end of each side casing and cut the bottom square to length.. Finish the window trim family handyman. set the head casing on the side casings, making sure the fillet overhangs evenly on both ends. then nail it to the wall framing. check the fit by holding the short mitered ends in place against the front crown molding..
- window stool, flat molding that attaches to interior side of windowsill - window casing, interior molding applied around the top and sides of window, and used to form the apron below - carpenter. With the apron and stool in place, now is the time to install the side casings. to determine their length, measure the distance from the stool to the top opening of the window, add 1/4" for reveal line.. How to install window trim. you don't even need a tape measure! courtesy of the family handyman next project . repeat all the same steps on the other side of the window, fitting first the top miter, and then marking and cutting the bottom one. nail the window casing trim into place. step 6..
