New Latex mattress and lower back pain

Let me start off by saying I have been a long time reader of this site and the other site you were on. I have been able to get all the information I needed by searching and reading the numerous posts. I have now gotten to a point where I need assistance of someone that has way more knowledge than me.

I moved into a new house and bought a king size bed this summer. After all my reading I had decided I was going to get a firm S mattress along with a latex topper for comfort. I found a great deal on a Rejuvenite latex topper. I went with the plush which is clearly labeled by Latex International as 19ILD. While shopping for the perfect coil mattress I visited stores in my area. I even brought my topper into one store and tried it on top of several mattresses.

Somewhere along the way I just decided to bite the bullet and go all latex. As I said above, I had already spent hours reading other peoples reviews and findings good and bad with the various companies. I even spoke to several on the phone and asked them questions as well. Despite your recommendations and others I decided to go with FBM for my core. I know in the past the reviews were hit or miss, but they had seemed to generally be better within the last few months.

I ordered a king sized Firm latex core. By FBM specs it is Talalay 36 ILD. I received my core the first week of September. As soon as I received it, I thought something was strange because it was 1 piece and wasn’t very jiggly or lively like I was expecting. I was concerned at first, but I put my Rujuvenite on top and gave it a try. We slept great at first, but my girlfriend complained it wasn’t soft enough so I bought a 1" latex topper from SLB in 14 ILD. When I got the new topper I tried a couple of configurations and eventually removed the Rejuvenite cover completely. So I had 6" FBM core ??, 3" L.I. 19 ILD, and 1" L.I. 14 ILD. It felt really good to me for about a month, but eventually I started having some lower back pain. My lower back pain is very mild, but stays with me most of the day. Usually by nighttime it has completely gone away, but returns when I wake up each morning. Now it has gotten to the point of staying with me all the time even though it doesn’t limit me in anyway. It is more of an annoyance, but occasionally someone will notice me favoring it or walking funny. Also, I am a combination back and side sleeper. I have been making an effort to be sure I’m not in a twisted position making my problem worse.

My bed is a platform bed with wood slats. After further inspection, I noticed quite a bit of sag in the slats under my side of the bed especially in the two slats under my rear end. I am 6’ and 215 lbs, so that wasn’t really surprising to me. I got out the 2 pieces of 1/4" pegboard I had originally bought when I got my bed for a base. I had tried them over top of the slats for a night or two when I first got the bed but it seemed way too hard to me so I removed them. After added the pegboard a second time, I seemed to get some relief for a few days, but the pain returned. Then I removed the 1" 14 ILD topper from SLB thinking my comfort layer was too soft, but the pain remained even after a couple of days. I even slept on just the core and 1" 14 ILD topper, but this is definitely too firm and doesn’t allow me to sink in enough and I had pressure points almost immediately. My core seems soft and giving in a way. If I sit on the side or just push down with my hand I can push way down near the bottom, but this seems normal from what others have said. It is definitely not hard as a rock or anything.

At first, I was thinking the difference between the my 19 ILD comfort layer and core was too great and I’m feeling that. Since the beginning I’ve thought about buying a 1" 28 ILD layer to see if it will help with the transition. After additional reading, my low back pain sounds like symptoms from my hips sinking in too much from the lack of support. I know the first component to blame will be my core from FBM since nobody knows what it is of course. This week I decided to remove the cover and inspect it. What I found is very interesting. It is has two labels on the side. One is Arpico 100% Natural Latex Foams., Richard Pieris Natural Foams Ltd. The other label has an arrow pointing up. Order No., Size, and Density and Reference number.

Upon further research it seems the core is probably Dunlop latex instead of the Talalay that FBM claimed? The Density is listed as 75 which would be soft according to the Arpico website. I’m not really sure if this is good or bad, but at least we have some idea of what FBM has sold me.

At this point I’m confused and don’t know which way to go next. Sorry for the long first post, but I have tried to give you all the information that has gotten me to this point. I appreciate any advice and recommendations you can give me to help alleviate my back pain.

Thanks in advance.

Hi RG24,

Well the good news is that the latex you received is good quality (although there is no way of knowing if FBM purchased it as seconds or used “other” sources). Arpico has made latex for a long time and they use the Dunlop process in their 100% natural latex.

The not so good news is that as you are mentioning it is their softest Dunlop and is certainly not Talalay. While Dunlop is usually rated in density rather than ILD … it would likely be in the range of mid 20’s. It would also have a softer side (the up arrow side) and a firmer side (with the arrow down). I would use the arrow down if you aren’t already doing that because the “bottom” will be firmer than the top which may help a little although probably not enough.

What this means is that your comfort layer is probably too thick (rather than too soft). With soft Dunlop, the first inch or so of compression will be quite soft and it would be the rough equivalent of having an inch of softer latex on top of firmer foam. This means that for side sleeping you would likely need another 2" of softer latex for good pressure relief. 1" (like the 14) will not be thick enough and it is also very soft so you would “go through” it and feel the firmness of the Dunlop underneath after it had initially compressed. With the 3" rejuvenite topper you would have the functional equivalent of 4" or so of softness in the comfort zone which is likely too thick and the cause of your alignment issues and back pain. Adding another 1" to this could make any alignment issues worse (as it seems to have over time). With the firm side of the Dunlop up … I would stick with the 3" topper if your girlfriend is OK with that.

I’m not sure what your girlfriends weight is (lighter weights usually need softer foam) but women are often more sensitive to pressure than men and like softer foams on top anyway. 19 is usually soft enough but if someone is used to the super soft polyfoam on top of most commercial mattresses … then this would be firmer than they were used to and may take a little getting used to. Did your girlfriend have actual pressure issues like numbness or arms falling asleep or was it just a matter of preference?

Adding another layer of 28 ILD would likely make the problem even worse as it would lower the effective ILD of the mattress (the dunlop is soft with initial compression but would get firmer with deeper compression than 28 ILD talalay) and your hips would probably sink down even further. Because the Dunlop is already soft you won’t need a transition layer between the talalay and the Dunlop core because the transition isn’t “sudden”.

Unfortunately, it sounds to me like 3" is too thick but 1" of course is too thin. I wonder what would happen if you phoned FBM with the “evidence” of what they sent you and asked them to send you something more appropriate (firmer) and closer to what you ordered so that the 3" rejuvenite would work better. If this worked better for you and your girlfriend still felt it was too firm … then you could always add the inch of 14 to her side alone.

It may be worth testing the 1" of 14 ILD doubled over on the Dunlop core (with the soft side up) to see how this works for pressure relief for you although I suspect that even though the thickness would be closer … the ILD may be a little soft so you may still feel the firmness of compressed Dunlop underneath it. It would certainly be worth a try though to see how it felt for you. If nothing else it may help “point to” the best solution.

With a King size bed especially … it is also really important that the support surface under the mattress is rigid, strong, flat, and well supported to the floor. It may be worth while to purchase a set of slats to replace the ones that are bowed. I like a slatted base more than a more solid base as it allows the mattress to breath better (even though the pegboard has holes so its better than plywood or MDF) and if you go in this direction I would also make sure that the slats are no more than 3" apart. It would also be important to make sure that the center beam on your bed was well supported to the floor with legs underneath it to keep it from sagging as any sag would also contribute to the back issues.

Unfortunately I don’t believe that FBM has gotten any better but many people don’t know how to tell the difference between what they received and what they should have received … and often even if they have a problem they will think it was just a poor choice rather than the wrong latex. I am grateful that you attached the pictures that you did.

So to recap … I would first try the 14 ILD folded over to 2" over the Dunlop with the soft side up to see how this seems to you … even if it’s for an hours nap.

Next I would see if there was any recourse to FBM for sending you the wrong product.

I would also check to see if your girlfriend’s sense that the 19 was too firm was based on preference or actual symptoms.

If she was OK with it … then I would try the 19 over the Dunlop with the firm side up (no inch of 14) for a few nights to see if it made any appreciable difference.

Let me know what happens and I appreciate you sharing your experience with the forum.



Thanks for the help and the new ideas. My girlfriend doesn’t stay with me all that often so it is really not a big deal to her for now, but she never really had any kind of negative results from sleeping on the latex in any of the configurations. I tried the 14 doubled up, but it is so soft I sank right through it almost no difference than just a single layer. So I took your suggestion and flipped the 6" core over. What I found was very interesting. I know you say that dunlop pieces are firmer at the bottom, and I have read this before. I didn’t realize how much difference there was. It is very noticeable even by pressing with my hands. I held the end up and pressed even on both sides and the top compressed quite a bit more than the bottom. Sorry I didn’t get any pictures of this. I tried, but I didn’t have enough hands. I had a big enough battle to get it flipped over by myself and back into the cover. A one piece 6" king sized dunlop core is a handful to say the least.

After flipping the core over I layed down and could defintely notice the increased firmness. Even after putting the 3" of 19 on top it is much firmer possibly even too firm now. I had a good nights sleep on it last night and woke up without any lower back pain. However, I did have back pain between my shoulder blades. I’m not sure if this is just the other soreness I had working its way out, or it is actually too firm now. I will give it a couple of more nights before trying the layer of 14 on top.

I have thought about contacting FBM like you said, but I’m scared that even if they were to do something they might send me something even worse. I think that it is possible if I had a 36ILD Talalay core it would be too soft for sure. I think the dunlop core upside down is going to give me something I can work with now. I have attached two pics of the core itself to give you an idea of how it looks if anyone is interested.

I will give you an update after a couple of days. Thanks again for you help.

Hi RG24,

I suspected this is what would happen but it was worth a try :slight_smile: 14 ILD talalay is very soft and heavier weights will sink into it deeper and feel the underlying foam more.

The difference will vary between different manufacturers as the size of the pincores as well as the natural settling of the latex and other factors can result in a variety of “top to bottom” differences. Each manufacturer has their own “secret” way of making their foam. A 6" core will also have a bigger difference than thinner layers (3" cut from the top will be different from 3" cut from the bottom). I’m glad the variance was enough to make a difference for you.

Pain in the upper back could also be a pillow issue if the pillow is too thick for back sleeping forcing your head forward too much (sort of like hunching over a computer for a long period of time and getting a similar pain). The latex may be firmer than the mattress you had before so the pillow may need to be a bit thinner.

With the “new” firmer core and with your larger size and weight … you may be OK with the inch of 14 ILD on top if you need it but I would tend to do what you suggested and try out the 3" of 19 by itself for a few days before making more adjustments just to give you time to fully assess each change. Thinner on top may be better for alignment as long as the pressure relief is good.

36 ILD talalay would probably be fine in terms of firmness but the odds that you would actually get what you ordered may still not be too great so if you can make what you have work that’s probably the best direction to go.

Thanks for sharing the pictures and the feedback.