Few bathrooms have enough places to hang towels. Stacking towel bars behind closed doors is a great way to remedy the shortage and use space efficiently. A flat or single-paneled door provides a crisp frame for three bars; furthermore, it's easier to affix them to a wooden door (as most are) than to a wallboard or a plaster wall. Hang the hardware according to package instructions, evenly spacing the bars along the length of the door.
