Beds Queen size and larger have a middle support rail with folding foot which provides support for wider mattresses. Some notes on mattress heights and Night table heights:
Bed mattress Height
The average bed height today is about 24-25 inches. At this height, your feet can reach the floor when you're seated on the edge of the mattress. An antique bed is quite high, built 36 inches off the floor, while a modern platform bed is typically only about 18 inches high. 90% of all beds are made for a 24-25" mattress height, but this ends up varying quite a bit when various thickness mattresses are used.
Benefits of Various Bed Heights
Higher beds may provide more storage room, assuming a taller-than-standard bed frame contributes to the height. Lower beds have a more modern look and may provide the aesthetic you like. Lower beds are also appropriate for children since they are easier to climb into and offer a shorter distance to fall if the child rolls out of bed. Older people sometimes like higher beds since they're easier to get in and out of.
Night Stand Heights
All our beds are built standard with 1/2" of space on all sides of the mattress or box spring, 3/4" space at the head and foot. If you would like a tighter spacing (3/8" on all sides) please make a note at the end of the order.