Hi bwomp,
You can see more of my thoughts and hesitations about the wire grid type of foundations in post #41 here.
Wire grid foundations can have some good advantages including strength, cost, and in some cases storage area under the bed and can be a reasonable choice for mattresses that have a “non latex” support core. While I don’t think that any risk of damage with an all latex mattress would be an issue in the short or medium term, especially with the version you chose with more wires and a smaller grid pattern, my own personal “risk tolerance” also tends towards the longer term possibilities as well even if they can’t be completely quantified or known for certain.
My longer term concern with these types of foundations for a mattress that has a latex base (and to a lesser degree a mattress with a polyfoam base layer) are because of the natural elasticity of latex and its tendency to sink into gaps and because the physical supportive area of a wire grid foundation is much less than a good slatted wood foundation (which would have somewhere in the range of a 50% supportive surface area which is much higher than a wire grid). There could also be some issue with latex or a polyfoam support core sinking into the gaps and causing “virtual impressions” or “soft spots” under the heavier parts of the body in the shorter term as well.
If cost or the benefits of having storage under the platform/foundation was my primary criteria, then I would lean towards the ones with more longitudinal wires and smaller gaps (as you are doing).
Some of the wire grid foundations come with a cover like this or which can be purchased separately (which may also fit other wire grid foundations of the same type) which would add a little bit of extra support in the gaps between the wires which I think would be a slight improvement. If I was to purchase one of these with an all latex mattress though (where there was latex directly on the wires) and in thinking about what I would do personally … my tendency would be to either buy a good quality cover using a woven (non stretchy), thick fabric or purchase my own fabric and attach it as tightly as I could to the top of the wire grid so that the surface was more evenly supportive.
Other options that may be even better yet would include adding an inch or two of very firm polyfoam in between the mattress and foundation (or reticulated form which is more breathable) or adding a rubberized coir bed rug like this or something like the vinyl lattice here (thanks to srockrae for the suggestion).
None of this is to say that any of this is absolutely necessary and may even be an “abundance of caution” on my part and it would depend on each person’s own “risk tolerance” but it is what I would do personally with one of these in combination with an all latex mattress because of the risk of the wires impressing into the latex over the medium or longer term.
A solid surface (like plywood) is another issue that is similar with many conflicting opinions but for me, unless there was a compelling reason to choose a non ventilating surface that made the tradeoff worthwhile (such as the choice of an adjustable bed), I would personally tend to use a more breathable and ventilating support surface. You can see more of my thoughts about this in post #10 here as well.
There are quite a number of these types of platform foundations and most of them have a high percentage of good reviews and they are all rated for over 2000 lbs … but the lower cost versions also seem to have a fairly large number of critical reviews that talk about the frame or legs bending and that indicate that the quality and strength of the steel and the foundation itself isn’t as high as it could be and there are also a percentage of them that appear to develop squeaking issues over time that may be difficult to locate and solve.
Phoenix