No, dado is not a typo; nor is it a doodad. Rather, it’s an architectural term that refers to the section of wall that is positioned between the chair rail and the baseboard below.
In colonial times, the dado was often covered with paneling or wainscoting to conceal moisture than would occasionally wick up from the ground and mar the wall.
Building construction has come a long way since then, but homeowners have an ongoing love affair with the dado because it affords so many wonderful options for home decorating. One of the most popular: painting the wall sections above and below the chair rail in two different colors.
If you love the idea of giving two-tone paint treatment to your walls, but don’t have a chair rail, don’t despair. You can even put away the hammer and nails. There’s a quick, easy, and inexpensive way to achieve the same look using nothing more than quality interior paint.
The trick is to use a painting technique known as "paneling" (or painting in strips) to mimic the look of a chair rail. This involves using painter’s tape to mask off a horizontal strip several inches wide at the desired height. Paint the wall above your imitation chair rail one color, then the wall below in a second color. Remove the tape, re-mask again, and paint the "chair rail".
While white is the most common color for a chair rail, using off-white or lightly tinted paint will make it harder to detect your deception. If you’re the obsessive type, you can even go one step further and carefully apply one or more thin "shadow lines" on the chair rail.
Voila! Instant chair rail and a whole new look for your room!