Contrary to what you may think, a split foundation is typically more supportive than a comparable one-piece foundation. With a large, one-piece foundation, there’s little reinforcing the center of the mattress. But with a split foundation, the center of your mattress is supported by the frame of each foundation piece. Split foundations offer other advantages. Because they come in two pieces, it is easier to move a split foundation in tight quarters. Also each piece will be much lighter than a single, one-piece foundation.