Window Seat Trim . The main thing is to choose quality window frames and their design. More than just a place to sit, it represents the promise of leisure. Farmhouse Style Window Seat Makeover Sarah Joy from sarahjoyblog.com Measure your old base molding to fit the front bottom of the window seat bench and then cut it. Beadboard photo by brent rarby/ipc images. Browse photos of window seat trim on houzz and find the best window seat trim pictures & ideas.