6+3 vs 3-3 inch layers

[phoenix]

Hi papalion,

As far as durability is concerned, I completely agree that a single 6-inch support core will be greater than two 3-inch cores of the same material and density.

In any practical terms there really wouldn’t be any meaningful difference in durability between two 3" layers and a single 6" core if all of them were the same type and blend of latex and the same firmness level.

With two 3-inch pieces, you may not have the top and bottom half of the same 6-inch piece of latex. You might get two tops, two bottoms, or the top of one and the bottom of another. Furthermore, even if you do get both halves of the same whole, it may no be that easy to discern which half is which. The orientation and placement of each individual piece as well as the order in which the two pieces are stacked with respect to one another can have a significant effect on how they interact with one another and a noticeable effect on the feel of the mattress as a whole.

Having the top and bottom half of the same core wouldn’t be important and even the ILD of different 6" cores with the same firmness rating can vary between different cores to some degree (and it will vary more with some types of latex than with others … see post #6 here) but these types of considerations would make choosing a mattress much more complex than it needs to be and in most cases they wouldn’t make enough difference to be meaningful for most people anyway…

In my original question however, I was not referring to two 3-inch pieces of the same ILD vs. a single 6-inch piece of the same latex. In such a case I know what I would do. What I was asking is if I’m looking for the feel of an 8" or 9" mattress with 2-3 inches of 19-ILD NR Talalay over 6 inches of 36-40 ILD NR Dunlop is there a specific advantage to using 3 inches of 34-36 ILD over 3 inches of 40-44 ILD that would outweigh any durability advantage of using a single 6-inch 36-40 ILD core?

Questions about “feel” are much too subjective and relative to each person to provide any meaningful answer. If the only difference between two mattresses were the relatively small differences in ILD you are mentioning some people may feel a difference when they lie on a mattress and some people wouldn’t and some people may feel a difference when they wake up in the morning (after sleeping on the mattress over the whole course of the night) and some people wouldn’t. I certainly wouldn’t consider a relatively small difference in ILD to be a significant enough durability factor to use durability as a basis for choosing one over the other and I would focus on choosing a mattress and layering combination that was the best “match” for you in terms of PPP.

For instance, there is no major difference between 36-ILD and 40-ILD. So in both cases it would be soft over firm. Is it possible however that because the delta between the top layer and the top of the middle layer in a three-layer design is smaller than the delta between the top layer and average density of the core layer in a two-layer design, the comfort layer would interact more with the support layer in the former than in the latter? In other words, for a side-sleeper like myself, would a three-layer design in which the two bottom layers are both much firmer than the comfort layer SOFT/FIRM/X-FIRM, work better with a 2-inch comfort layer than a 3-inch top of the same ILD? And likewise, will the two-layer design SOFT/FIRM work best with a 3-inch comfort layer?

I think you may be getting overinvolved in some of the finer details of mattress design and theory and I would keep in mind that mattress design and theory is more of an “art” than an exact science. The most likely outcome of this type of analysis can be information overload and “paralysis by analysis”.

You are the only one that can feel what you feel on a mattress and there are too many unknowns, variables, and individual preferences and sensitivities involved to be able to use a formula or for anyone to be able to predict how a combination of layers will feel to you or to make a specific suggestion or recommendation about which mattress or combination of materials and components would be the best “match” for you in terms of PPP (Posture and alignment, Pressure relief, and Personal preferences) based on specs (either yours or a mattress) or “theory at a distance” that can possibly be more accurate than your own careful testing or personal sleeping experience … hopefully using the testing guidelines in the tutorial post (see mattress firmness/comfort levels in post #2 here).

Unless you have a great deal of knowledge and experience with different types of mattress materials and specs and different layering combinations and how they combine together and can translate them into your own “real life” experience that can be unique to you … I would tend to avoid using ILD numbers or other complex specs to try and predict how a mattress will feel for you and focus more on your own actual testing and experience or if you can’t test a mattress in person then a more detailed phone conversation with an online manufacturer or retailer. If you try to become an “expert” in mattress theory and design it could take you years to learn enough to design your own mattress using specs that can be more complex than you may realize and I would focus more on your own testing which “bypasses” the need to know anything about specs at all or alternatively talking to knowledgeable and experienced manufacturers or retailers who already know what you would otherwise need to learn before you would be able to choose a mattress.

Phoenix