I see some conflicting information, but it seems like a lot of mattresses have ventilation problems if they are placed on a solid wood surface, like the solid plywood on top of a platform or storage bed (ie. no slats).
What mattresses would be good on top of a solid wood platform bed? I’ve read that memory foam would work, but that doesn’t work really well for a hot sleeper does it?
Are there ‘fixes’ that can create some circulation between the platfor and the mattress? (assume a tall platform bed, without much height allowance for a boxspring).
I’m not a fan of a solid surface platform for any mattress unless there is a compelling reason to choose it that offsets the additional risk (such as wanting an adjustable bed that has a solid surface).
With a memory foam mattress the polyfoam in the support layers would be the foam that was closest to the platform and in most cases polyfoam is more breathable than memory foam. Latex is generally more breathable than both.
The type of surface under your mattress wouldn’t be as much about the sleeping temperature of the mattress as it would about allowing the mattress to ventilate and reducing the risk of mold, mildew, and dust mites in the mattress. There is more about a solid surface vs a slatted surface under a mattress in post #10 here.
A google search on mold mattress will give you an idea that mold can certainly happen under a mattress depending on the risk factors involved although it seems to be more common with memory foam which is a less breathable and warmer foam which can allow for more accumulation of moisture and a higher temperature inside a mattress which is a more conducive environment for mold and mildew.
Something like the bed rug here or one of the slat conversions here (which has no flex at all) or even one of the Ikea slatted bed bases here (which has some flex which may change how the mattress feels and performs) can also provide good support and airflow under a mattress and are also economical.