The Many Benefits of Bunk Beds With Steps Bunk Bed Terms The size for a bunk bed basically depends on the bed size utilized. About 90% of all bunk beds utilized in the United States would be twin over twin mattresses. There are other options, however. For instance, twin over full bunk beds also exist which provide more space above the bunk beds than below it. Futon bunk beds are sometimes fitted with stairs, which makes them double bunk beds with a bottom bunk and a top bunk. A Few Considerations When selecting a mattress of bunk beds with steps, there are some things to consider. If the stairs would be placed on the lower bunk of the bed, then the bed and the stairs could be bought as one unit. This would allow for easy access to the lower bunk beds for washing or cleaning. However, there is a trade off for portability, as the top bunk has to remain open to allow access. The benefit of having two beds is that the children can sleep separately. It is also possible to on