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, Iām 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 am very interested in staying with latex and believe Iād do best in something akin to 1.8 high density polyurethane foam or the firmness of a crib mattress.
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 āour dunlop latex is from Vietnam and is most likely a different vendor than the previous company you may have been talking toā and āI am not sure what further information you are wanting in regards to our dunlopā. And yet add their 7" two layer 3" (32 ILD) and 3" (63 IDL) which Iām considering buying āmightā feel firmer than what Iām currently sleeping on - I donāt want to waste anyoneās time or valuable resources so I need a more certain response before proceeding.
Experts, what is the maximum/highest firmness for dunlop latex? Is what Iām looking for possible to achieve with latex?
Iām sorry youāre āwaking up soreā with your new mattress. While itās 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 donāt list your sleeping style nor BMI, so itās possible you may personally prefer even firmer/thicker materials.
As far as 32-36 ILD being the āhighest achievableā via the Dunlop process, that wouldnāt be correct. While I wasnāt 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.
Density of polyfoam isnāt indicative of firmness, and polyfoam compresses differently and doesnāt āfirm up as fastā (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.
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, itās 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.
Iām not exactly sure what youāre desiring for a more ācertain responseā 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 ādeep supportā than your current mattress. But I unfortunately canāt predict if this is the solution to your needs nor what you may find preferable.
I donāt know that there is a āmaximumā Dunlop density achievable, but Iām 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 āfirmestā Dunlop that is ācommonlyā offered is in the 90-95 range.
Phoenix, thank you so very much for your speedy and detailed response, so appreciated.
Iāll likely respond with more details later as my time parenting a toddler allows.
To respond to some mayor points here. In most mattresses I feel like the ātoo softā in the back alignment diagram in the post you kindly included. I previously had a cheap and too soft coil and poly foam mattress from Ikea and I believe thatās where my issues stem from. My husband and I are petite people; I am 5ā3" tall, 130 lbs and a BMI of 23.0, my husband is 5ā6", 146 lbs with a BMI of 23.6. I have a herniated disk at L1/S1, so yes lower back problem indeed. We definitively prefer firm sleeping surfaces and sleep in all positions.
The first seller states on their site their GOLS organic Dunlop is sourced from ARPICO in Sri Lanka. The second seller states their 100% natural latex is sourced from Lien A in Vietnam. The first seller says their layer has 90 density. The second seller says the layers Iām considering have a 5.9 and 6.0 density respectively. How can I use these numbers for an apples to apples comparison of the higher firmness Iām looking for? Could the Lien A latex contain additives to get to the higher ILD?
Maybe a zoned core would be best for us. Would you know which TMU sellers stock GOLS organic Dunlop zoned cores in the US?
Iām sorry to learn about your low back issues. But it seems that you certainly prefer a firmer sleeping surface, as what you have right now is generally considered quite firm.
As I commented previously, the density will be the more reliable comparison between two Dunlop layers, and the ILD isnāt quite as accurate unless a specific core of foam has been tested. Overall, the hardness of the latex can be influenced by such factors as the density, type and mix of the latex, fillers, method of vulcanization, and the size and distribution of the pin-holes.
Most Dunlop manufacturers test ILD using a 6" core. The ILD rating is then taken at either a 25% compression or at a 40% compression. The most common measurement for cores in North America is 25%. If the core is 6" then 25% would be 1.5", and 40% compression would be 2.4". So the 40% ILD number would be higher than the 25% ILD number for the same latex. With Dunlop, some ILDs are estimated via formulas the manufactures have set up. Others are actual measurements.
In some charts I have for Arpico (Iām not sure of the actual blend of Dunlop), they list āpossibleā ILDs for their 85 (+/-5) kg/M3 in the 31-36 ILD range (at 40% compression). At 95 (+/- 5) kg/M3, they list the possible ILD range as 39-45 ILD.
The numbers you were given for Lien A are in lb/ft3, so the 6 would translate roughly to a 95 kg/M3 density. This is sometimes termed an XX Firm, and in the attached chart you can see it rates as an approximate 46 ILD, but Iām not sure of the compression of this (25% or 40%).
Thereās another chart I have (see attached) of common Dunlop ratings from around the world, and in this chart (at 40% compression), there is a representation of Dunlop in the 95-100 kg/M3 range listed with an approximate ILD of 59-66, of which the 63 ILD you are being quoted would fall right in the middle.
All of this goes to show you that ILDs are not quite as clear-cut a manner to compare Dunlop latex, and while the different piece of latex youāre considering should be firmer than your current product, I donāt think the difference will be as dramatic as the ILDs have been represented to you, for the reasons in ILD representation as Iāve described.
As for site members who sell zoned latex cores, you may wish to investigate: Arizona Premium FloBeds has a very unique zoned system SleepEZ may be able to procure a zoned Dunlop core for you, but youād have to phone them
Most people that are looking for an āorganicā mattress or materials are usually concerned more with āsafetyā than whether the materials have an actual organic certification and they usually arenāt aware that an organic certification isnāt the same thing as a safety certification. There is more information about the three different levels of organic certifications in post #2 here and some of the benefits of an organic certification in post #3 here and there is more about the different types of organic and safety certifications such as Oeko-tex, Eco-Institut, Greenguard Gold, C2C, and CertiPUR-US in post #2 here and more about some of the differences between organic and safety certifications in post #2 here and there are also some comments in post #42 here that can help you decide whether an organic certification is important to you for environmental, social, or personal reasons or whether a āsafetyā certification is enough.