standard bunk bed|thumb|a bunk bed  a bunk bed is a type of bed in which one bed frame is stacked on top of another. the nature of bunk beds allows two or more people to sleep in the same room while maximizing available floor space for activities. this leads to them being used in places with limited floor space, such as on ships and in army garrisons or in places where bedspace needs to be maximized, such as dormitories, summer camp cabins, hostels, children's rooms, prison cells, or university residence halls. bunk beds are normally supported by four poles or pillars, one at each corner of the bed. a ladder is used to get to the upper bed, which is normally surrounded by a railing to prevent the sleeper from falling out. some models also have a privacy curtain for the lower bunk. because of the need for a ladder and the height of the bed, the top bunk of a bunkbed is not recommended for children under six years of age. a loft bed is an elevated bed similar to a bunk bed, but without the lower beds - freeing floor space for other furniture (such as a desk) which might be built into the loft bed. ==types == the most common type is the standard bunk bed which has two same size mattresses stacked one directly over the other. a twin over full bunk bed is arranged as a standard except that the bottom mattress is a full size and the upper is a twin size. a futon bunk is also arranged like a standard bunk except the lower bunk is a western-style futon couch which converts into a bed rather than a standard mattress. futon bunks can be used to save space in small apartments or rooms, because the lower bed converts to a couch for use during the daytime. in an l-shape bunk the bottom bed is oriented at a right angle to the top bed such that when viewed from above the beds form an l. this also creates a small alcove where a desk or bookshelf can be placed. a loft bed denotes a bunk bed that has only the top bunk, creating an open space underneath that can be occupied by a chest, drawers, or even a work area."how to build a dorm loft", elephant staircasetim carter, "building a loft bed" and "build a loft bed", ask the builder this makes loft beds an efficient use of small spaces by utilizing the entire vertical area that would otherwise be left unused. some loft beds even 
Beds