Hi Cataldo,
Sorry for missing your question. Sometimes it happens when there are multiple posters posting in the same thread.
If you mean a frame like this then I certainly wouldn’t put a mattress on it directly. It’s meant to support a box spring or a foundation … not a mattress which would sink right through it. I also wouldn’t use a box spring at all (box springs are the ones that have some type of springs inside that flex). With an all foam mattress, a rigid non flexing foundation or platform which has a rigid, evenly supportive, and non flexing surface is usually the best choice.
The foundation thread here has more information and links to many options that would be suitable for different types of mattresses in many budget ranges. Brooklyn Bedding also sells a foundation/frame that would work well for their mattress.
Phoenix