While poking around on the mattress.net site, I came across their 3 Zone Dunlop core. This seems like it might work well for me because I noticed while trying out beds that when it is too firm, my shoulder gets pressure, and when it is too soft, my hips “hammock”. I thought I might have them make me a bed out of it with their usual 2" soft Talalay topper.
Based on what I read, Dunlop’s characteristics might be what I prefer, such as a more damped feeling, and also more “progressive” in spring rate, i.e. it’s firmness ramps up more when you press harder on it.
There’s only two things that concern me about this core. One is that it is only 20% natural latex. I think more natural latex would make Dunlop more durable? How much of a difference are we talking about vs 100% natural? The second is that it achieves the zoning through making big holes in the mattress. How is that going to affect the “compression modulus” of the material?
As an aside, I was thinking of having them purposely make a mattress cover that has an extra 2" or so of room, in case I want to wedge in another layer somewhere as a tweak. What are your thoughts on this?
All latex is a durable material relative to other types of foam but I would agree with you that this would be less durable (and also less resilient and less contouring) than 100% natural molded Dunlop.
The “how much” is impossible to answer because it would depend on many factors (see post #4 here about the factors involved in the relative durability and useful life of a mattress) but I would put it in a more durable category than poyfoam and less durable than 100% natural molded Dunlop. If it’s being used with comfort layers on top of it then it would be more durable than it would if you were sleeping on it directly.
Almost all latex has pincores (the holes you are talking about) and this won’t affect the durability of the latex any more than any softer material would be less durable than a firmer material of the same type (softness is a secondary durability factor). Since the firmer zone is under the heaviest part of the body this would add to its durability compared to the same layer that had the same softness as the top and bottom zones throughout. It wouldn’t affect the compression modulus … it just starts off softer.
They could also give you more insights and information because they work with this type of latex on an ongoing basis.
Outside of the zoning … I think the main reason to choose it vs a similar 100% natural molded Dunlop layer would be someone who wanted the benefits of latex but was on a more limited budget.
This would be a good idea if you added the extra 2" and probably not as good an idea if you didn’t (the cover would be very loose and subject to shifting, bunching, and wrinkling).
Thanks again for answering in a timely manner. I think what I will do is have them make the cover extra tall, and I will add in myself a temporary layer of cheap hard foam to use as a spacer at the bottom. (any suggestions for something that is cheaper than polyfoam and not outgassing?) After I get more familiar with the mattress and develop more refined preferences, I can go back and wedge in a real latex layer somewhere. Or leave it as-is if it is fine.
I don’t think you will find any suitable mattress materials that are cheaper than polyfoam. For temporary use I would use no less than 1.5 lb firm polyfoam and 1.8 or higher would be more durable. Most cities have foam shops where you can buy polyfoam but there are some online sources listed in post #4 here as well.
You can also read more about how natural rubber compares to synthetic rubber in terms of aging and durability in post #2 here (I forgot to link it in my last reply).
I was wondering whether I should have them add an extra inch or two inches. Right now it is 5.5 core + 2" 22 ILD topper. I mean, what are the circumstances where I would need to add a yet firmer layer of foam under the 32-35-32 dunlop core? And usually, what would be a maximal thickness of a comfort layer?
I realized today that instead of buying foam for a spacer, I can use an industrial sewing machine to hem the extra height of the mattress case.
More polyfoam on the bottom would change the “feel” to some degree and make the mattress softer (firmer foam would still be softer than the foundation that the mattress would otherwise sit on and thicker mattresses generally “act” softer). Sometimes polyfoam is added instead of more latex in the deeper layers because it’s a lower cost material and the deepest layers have less effect on the “feel” of a mattress. Polyfoam layers are also sometimes added on the bottom of a latex mattress (usually glued) because it’s stiffer and can make the latex easier to build, handle and move (without tearing) and it can also be used if the mattress is on a foundation that has slats that are wider apart because the polyfoam isn’t as elastic as latex so it doesn’t sink into any gaps between the slats as easily.
There is no “maximal” or optimal" comfort layer because it depends on the person and on the overall design of the mattress and how all the layers interact together with each other and with the person on the mattress.
I caution people on a regular basis about using comfort layers that may be too thick or soft for them yes.
There are some links to some generic guidelines in mattress firmness/comfort levels in post #2 here but there are too many unknowns, variables, and individual preferences to use generic guidelines, specs, or “theory at a distance” as a way to choose an optimal mattress for any specific person. People and bodies can be very different from each other