memory foam as middle layer

[phoenix]

Hi heywannaplay,

I’m not quite sure if you’re asking a question or just making a statement, but I’ll comment upon a few of the things that you said in case it is helpful.

memory foam as i understand it is normally a comfort layer but can be a support layer if of reasonable size and density.

Memory foam is indeed most commonly used in the upper layers of a mattress, as a comfort layer or sometimes as a “transition” layer between the comfort layers and the support core. It would not be appropriate or suitable to be used as a support core, as memory foam is generally quite plush and does not provide prevention of “bottoming out”. And like polyfoam, the hardness of memory foam is not directly related to the density.

So many companies now use a smallish (1 or 2 inch) layer below a similar polyfoam layer. Now here the polyfoam would be more supportive than the memory foam so what is the benefit to having the memory foam? just for marketing purposes.

Memory foam provides a comfort, just like any other foam, and where it is placed within a mattress (upper or deeper comfort layers) would be the result of the level of comfort that the mattress designer was attempting to achieve.

Further since memory foam is activated by body heat its effectiveness is again reduced.

The deeper a memory foam layer is placed within a mattress, the less susceptible it will be to the impact of body heat, which means that the viscous nature of the foam won’t tend to change as much as if the layer was on top of the mattress. I wouldn’t term this as having the “effectiveness reduced”, but instead as having the change in viscosity reduced, which may be the goal of the mattress designer by locating the layer deeper within the mattress. Without our crystal ball, we can not infer the reason for the design of the mattress, only the final result.

So multiple issues of when does a comfort layer become both comforting and supportive. compression modulus?

Comfort layers are generally meant to be just that – layers that provide comfort – and not as concerned with support. Latex does have a unique ability to be quite point elastic but then also “firm up” as weight is applied (can have a higher support factor or compression modulus). Some true high resilience polyfoams can also have such characteristics.

There is more about primary or “deep” support and secondary or “surface” support and their relationship to firmness and pressure relief and the “roles” of different layers in a mattress in post #2 here and in post #4 here that may also be helpful in clarifying the difference between “support” and “pressure relief” and “feel” that may be useful as well.

but its hard enough to get basic specs from these companies let alone this sort of figure.

I’m not sure what “sort of figure” you’re attempting to acquire. All the information you need to know is in this article. While the specs that affect the quality and durability of the layers and components are important to know … when you are testing a mattress locally then disclosing “comfort specs”, such as ILD/IFD, isn’t really necessary or even an important part of transparency because with careful testing your body will tell you much more about whether any specific combination of layers or components or any specific mattress is a good “match” for you in terms of comfort, firmness, and PPP (Posture and alignment, Pressure relief, and your own Personal preferences). Such information as this or the compression modulus of a specific foam layer (or even of a finished mattress, which is not something that is measured) would be completely meaningless and only add to the confusion for most consumers anyway.

Phoenix