G.B.
Bunk beds are extremely dangerous. My friend from Jr. high all the way through high school lost her son when he fell off the top bunk. He was not goofing off or roughhousing, nothing like that, he just fell off and was dead. Please find another way. The beds can go differently and who knows, you might find a 3 bedroom house you like and move in a year or two when they are big enough to need their own beds.