Firmness question, not sure if too soft or too firm.

[phoenix]

Hi Tenmand,

Hi, I got a few questions about firmness ratings. My wife and I are 5’8", weight between 120-145lbs side/back sleepers. My current mattress is a DIY with pieces from FBM (FoamByMail, Foam Factory). It’s made up of 3" talalay latex (32 ILD) on top and 5" of lux-r foam (50 ILD) on the bottom. There are inconsistencies in the FBM latex; for example, some parts feel firmer/softer than others, but overall the mattress has been very comfortable.

This would be normal for Dunlop latex which can have a range of ILD’s across the surface. Unfortunately FBM also doesn’t accurately list what they are selling so there is no way to really know the ILD of what they sell or use what you ordered as a reference point. This is part of the reason I don’t recommend them as a source (see post #2 here along with post #2 here).

Recently, I get aches/soreness around my shoulders/upperback, while my hips/lowerback are fine. It feels like the 3" 32 ILD latex is too soft, and the 5" 50 ILD lux-r foam is too firm. Too soft and too firm at same time, does that even make sense?

This makes perfect sense to me. A mattress is always a combination of softness in the comfort layes and firmness in the support layers and if the top layers are either too soft or two thick and the mattress doesn’t hav a transition layer in between … then you can “go thrrough” the softer comfort layer and feel more of the firmness of the support layers below them. This is what I call a “differential” design and it’s important in this to get the thickness and softness of the comfort layer correct so that it isolates you from the transition between them. The best thickness and softness will depend on the body type and sleeping style of the person as well as their individual preferences.

1 – add an inch of 40 ILD Everlon between the latex and lux-r.
2 – replace the 32 ILD talalay with a 36 ILD talalay from one of the vendors here.

Which option should I go with?

I certainly wouldn’t recommend FBM for a purchase where knowing what you were really buying was important or for any “application critical” purchase.

I would tend towards the latex although you may only need an extra inch or two on top rather than a firmer transition layer like you are thinking (in between the latex and the polyfoam). Without knowing the ILD of the top layer you have it’s not possible to really use it as a reference point except based on it’s “feel” for you and it will depend on both body type and individual preference. If you did decide to add a transition layer … then a couple of inches in a medium range (such as the 32) would be “average” especially for your lighter weight but if it’s the latex itself that is causing the firmness issue then this may not help as much as you hope because you may just need a little extra thickness and softness in the comfort layer itself. Post #8 here has some guidelines for choosing a topper (and has a link to a post with some good sources) that may be helpful.

One other option that may be worth considering as a low risk experiment is to try a cheap 1" - 2" polyfoam topper from a big box store like Walmart or Costco etc which has a good return policy so you can experiment a bit to see if adding a little thickness/softness to your comfort layer will make the difference you want. If it does you could either replace it yearly or so as it softens and degrades or you could use it as a rough guideline for a longer lasting latex topper.

Part of this as well will depend on how much room you have in your mattress cover because if you “squish” too much latex in it, it will make the layers firmer than they would otherwise be.

Hope this helps

Phoenix