Latex - Maximum/Highest Firmness or Indentation Load Deflection (ILD) for Dunlop

[phoenix]

Hi aldaarias,

Welcome to the Mattress Forum!

I recently bought a 7" firm single layer dunlop latex mattress (32-36 ILD / Density: 90) from a TMU member company - the firmest they sell. Great price, certified organic materials, great service but my back is unhappy, I’m waking up with muscle soreness. This manufacturer tells me I should have purchased something softer from them adding 32-36 IDL is the highest achievable with the dunlop process.

I’m sorry you’re “waking up sore” with your new mattress. While it’s not possible for me to diagnose soreness issues via an online forum, there is some information about the many different 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. Pressure points and general soreness tend to be a surface comfort issue (usually requiring thicker/softer comfort materials), which could be why you received the recommendation that you did about choosing something slightly softer. Many low back issues - ones which can take most of the day to overcome - tend to be alignment related, which quite often points toward inadequate deep support. The mattress you have is generally regarded as quite firm, so this may not necessarily be the case, but you also don’t list your sleeping style nor BMI, so it’s possible you may personally prefer even firmer/thicker materials.

As far as 32-36 ILD being the “highest achievable” via the Dunlop process, that wouldn’t be correct. While I wasn’t part of your conversation, my guess would be that either the manufacturer was referencing the firmest Dunlop that they offer, or the firmest Dunlop that their supplier provides them.

I am very interested in staying with latex and believe I’d do best in something akin to 1.8 high density polyurethane foam or the firmness of a crib mattress.

Density of polyfoam isn’t indicative of firmness, and polyfoam compresses differently and doesn’t “firm up as fast” (has a lower compression modulus generally) than latex. Dunlop will tend to be a bit softer during its initial compression, then firm up as more weight is applied. But it will be more point elastic than a typical base polyfoam.

I found another TMU participating manufacturer who lists a 63 ILD for dunlop mattresses and tells me in the future they will carry even higher ILD dunlop. I asked for an explanation of how this is achievable and the response was “our dunlop latex is from Vietnam and is most likely a different vendor than the previous company you may have been talking to” and “I am not sure what further information you are wanting in regards to our dunlop”.

Dunlop latex is more accurately compared via density as opposed to ILD. While ILD estimates can certainly give you a good idea of the comfort, ILDs are ranges, and the ranges are larger (generally+/-4 or so) for Dunlop versus Talalay (generally +/- 2 or so). There are also variations in how the ILD is calculated (thickness of the piece tested, the percentage of compression, hold time, and so on), so unless a specific piece of Dunlop foam was measured, it’s usually more accurate to compare Dunlop via density.

With that being said, if a company has a piece of Dunlop that they say is rated at 63 ILD, this most certainly would be a very firm piece of Dunlop, and could likely be something tested at a 40% compression in the 95-100 kg/M3 range for density.

Different Dunlop pourers in different parts of the world will manufacture their latex to suit those specific areas, and in the case of Vietnam (Lien A, for example) they produce 95+ kg/M3 density Dunlop that, depending upon the method of measurement, would be well over a 50 ILD. Firmer mattresses are more common in Asia in the east and southeast regions.

And yet add their 7" two layer 3" (32 ILD) and 3" (63 IDL) which I’m considering buying “might” feel firmer than what I’m currently sleeping on - I don’t want to waste anyone’s time or valuable resources so I need a more certain response before proceeding.

I’m not exactly sure what you’re desiring for a more “certain response” about. If you had two 3" layers of Dunlop at 32 and 63 ILD, and if the Dunlop was measured the same and of the same style (natural, blended or synthetic) as what you currently have, this would have firmer “deep support” than your current mattress. But I unfortunately can’t predict if this is the solution to your needs nor what you may find preferable.

Experts, what is the maximum/highest firmness for dunlop latex? Is what I’m looking for possible to achieve with latex?

I don’t know that there is a “maximum” Dunlop density achievable, but I’m sure the different latex foam pourers have found different densities they can consistently produce at the firmest levels. There are manufacturers producing Dunlop over 100 kg/M3 for use in mattresses, which would be quite firm, and there are ones producing even firmer latex for the equine industry! But in general, in North America, the “firmest” Dunlop that is “commonly” offered is in the 90-95 range.

Phoenix