When bringing a mattress up the stairs or through a tight hallway or doorway, you can bend the mattress and squeeze it through because mattresses are flexible. You do not have this option with a box spring since it is a solid piece.
All king size box springs come in 2 pieces. This is because most people would not be able to fit a full king size box spring into their room without squeezing and bending along the way! This is called a king split box spring.
Queen box springs also come in split versions! If you are having trouble bringing a full size queen box spring through a hallway or up the stairs you can opt for a queen split box spring which will make your life a lot easier by bringing in 2 separate smaller pieces instead!
For more information on split box springs visit our blog: https://www.nationalmattress.ca/my-box-spring-does-not-fit-up-my-stairs