Stair Stringers and Brackets
No matter what type of staircase you have in your home, there's usually a way to add trim so that the stairs will complement the surrounding décor. In a closed or boxed staircase with walls on at least one side, adding stair stringers can give the staircase a whole new look. Stringers are large, flat panels that range from 1 to 2 feet in height (30.5 to 61 centimeters). They're installed along the joint between the stairs and the wall and typically run at the same angle as the staircase. The top and bottom of each panel may be finished with decorative molding, or it can be left unfinished for a simpler look. While stringers are mostly used for aesthetic purposes, they can also provide some structural support for older staircases [source: Carter].
On open staircases, homeowners can add stair brackets to lend style and flair. These brackets are installed in the triangular area on either side of the staircase where the risers and treads meet. They're often made from wood, though some older units are fabricated from iron.