Topic: single bunk over double bed

5 Factors to Consider Before Buying a Bunk Bed A bunk bed is a great way to save space in children's rooms. But, before you purchase one, consider the following factors: Mattress size: Most bunk beds come with twin-over-twin or twin XL mattress options, which are great for rooms with small spaces. Twin mattresses are also easier to dress than queen-sized ones. ...