A memory foam mattress foundation is a platform that is put under a memory foam mattress. Unlike regular mattresses that have springs inside of them, memory foam mattresses have a tendency to sink through cracks, so they require a different type of foundation.
A platform foundation is best for memory foam mattresses, since it has a solid base, and there are no cracks for the mattress to sink into. Memory foam mattresses do not have the support of springs, so they need to be fully supported by a foundation or the floor itself. Slatted foundations must have slats that are 3 inches or less apart to support a memory foam mattress.