A window sill is the bottom pice of trim or the ledge at the bottom of the window.They are a necessary part of the window, by keeping out rain and making windows more energy efficient. Sills are a part of the window trim, which also included the head casing, side camps and the apron. All these parts play a role in keeping the window structurally sound. The window lintel is a structural horizontal block that is placed between two vertical supports.
There are many designs in which a window sill and lintel can be constructed, therefore we like to view the current house model and construct the window sills and lintels according to that.