This 3-1/2″ 1867 style casing offers an old farmhouse or heritage design. Sometimes corner blocks are used with this style of trim. Casing is used to trim around doors and windows. It covers the gap between the drywall and the jamb. Casing is often the most prominent trim feature in your home and should be thicker than the baseboard. To increase the width and depth of the casing you can add a back band.