Hello,
I thought I had done my research and bought a king (not-split) latex mattress from Costco that is 3 inches of 19 ILD over 6 inches of 32 ILD. (Didn’t realize until I found your site that I could customize). I am experiencing increased back pain. I am 5’9 weighing 135 pounds. My husband is not experiencing problems (6’ 220). I am thinking about getting a Twin XL latex topper to make the mattress firmer for me and place it under the mattress pad. Would this work? Would you recommend a firm or medium firm? Also, I was hoping to use just the 1 inch, so as to not create a big difference, which is the whole reason I didn’t get the split mattress in the first place. Thank you!
Hi CDLockwood,
Welcome to the Mattress Forum! 
For reference, the Sleep Science Natural Latex mattress uses good quality materials but is somewhat more costly than other mattresses that use the same materials and have a very similar design (6" Talalay support core under a 3" Talalay comfort layer with a quilted wool cover) that are made by some of the manufacturers that are members of this site and sell latex mattresses online listed in post #21 here. It likely also has a little less wool in the quilting than some of the other online options you have (it needs an inherent fire barrier and doesn’t use just the wool as a fire retardant layer). The fire barrier is likely a viscose / silica (not wool) inherent fabric (see post #2 here) but there are also other types of inherent fire barriers as well. It also doesn’t have options to rearrange or exchange layers, as you mentioned. The latex they use is most likely blended Talalay (30% natural and 70% synthetic latex) and not 100% natural latex, which doesn’t come in the specific ILD’s (19 and 32) that they mention.
You didn’t mention how long you’ve had your mattress, but there is a period of adjustment to any new mattress where you lose some of your “learned alignment” and the mattress also adjusts to you a bit as it loses some of its “false firmness”. You also weren’t specific about your back pain (location) or sleeping position/style, so there is some general information about the many different pains/symptoms that people may experience on a mattress and some of the most common causes behind them in post #2 here that may be helpful but the most common reason for lower back pain is a mattress that has comfort layers that are too thick/soft or a support core that is too soft.
What you’re describing is placing a dominant “firmer” layer as the uppermost layer of a mattress. Dominant layering can have a very different “feel” to a more traditional progressive layering where the softest layers are on top. It provides a firmer sleeping surface and the surface foam compresses less than it would if it was a softer layer and tends to “bend” more into the softer layer below it so it can still provide good pressure relief and “give” under the pressure points (as long as the dominant layer isn’t too thick and prevents the softer layer below it from “coming through” or compressing enough).
It is a good solution for people who prefer a firmer, “crisper”, or less “mushy” surface feel or greater freedom of movement and don’t like the feeling of sinking in directly to the top foam layer as much but still need good pressure relief that comes from underneath.
The “feel” and performance of dominant layering can be “nuanced” or changed a lot depending on the thickness of the dominant layer and it’s firmness relative to the ILD of the layers below it and the thickness of the softer layers underneath. It can reduce the amount that the heavier parts of the body sink down into the softer layers of the mattress (especially if the softer layers underneath aren’t too thick) but still provide good pressure relief under the pressure points (again depending on the thickness of the firmer layer). So it can be a way to increase some surface plushness without the product allowing you to sink in too deeply initially.
Some examples of other posts that talk about dominant (or dominating) layers in one form or another are here and here and here.
As for selecting a topper, there are some guidelines in post #8 here and the posts to which it links. Most people adding a topper are looking to add plushness and not firmness, so I’m not sure how much of an impact 1" of “medium” or “medium-firm” latex would have for you. As far as a firmness, I wouldn’t be able to predict what you might prefer, as there are far too many personal variables involved. Also, the terms “medium” and “medium-firm” are not standardized, so you’d have better luck with comparing ILDs to the 19 ILD layer used in your current mattress, probably looking for something in the mid to upper 20s for the ILD, depending upon your preference.
Phoenix
Hello,
Thank you for your quick reply! For clarification, I am a side sleeper, and the back pain is lower back. I read the posts that you linked. Just a follow up question. I was thinking about buying from Sleep on Latex, the one inch King topper in their medium firm, which is 30 ILD. (My husband states he would like a firmer topper also) I thought that it should be one inch because the softness from the 19 ILD layer would still be there as a pressure point reliever. But it seems that you indicated in your response that you were not sure that one inch would make a difference. Am I misinterpreting or should I perhaps go with the two inch? So grateful for this forum!
Hi CDLockwood,
While I can’t “feel what you feel”, in general for a side sleeper in the situation that you’ve described and to achieve a “significant” difference in firmness, the 2" would produce a more noticeable result than the 1".
Phoenix