Yes. Both mattress foundations and platform beds can offer a close match to the firmness and support you’d get from the floor. Both of these options come with wooden slats to support the mattress as it sits on top of them. These slats are usually interspersed at intervals of 2 to 3 inches. But if you get a foundation with more slats or even a solid plank in place of slats, it will offer you similar support to the floor without all the yuckiness that comes with actually putting your mattress down there. For extra support, you can also slide a bunky board between your mattress and your bed base.