observations & Qs about latex mattresses

Discussions General Mattresses Questions
8

Hi Phoenix,

I’m still digesting your terrific post above on cover/ticking. I do suspect your intuition is correct about a 2" comfort layering being better for side sleepers relative to 1". It has been an interesting but sometimes confusing search. Today, I revisited the OMI mattresses and Essentia as well. The one positive about today’s experimentation is that my faith has been renewed in cotton cover and wool quilting (OMI). These were much softer and less taught than the custom comfort cotton/wool covers. So I don’t have to be as concerned about that aspect, especially considering that wool has so many good properties. So cotton/wool or bamboo/wool would both seem OK in the cover.

I tried the OMI lago, duo, terra and another that had a 7" core plus 2" topper. The terra was too soft and squishy for my taste. Of the others, the lago was the medium firmness and closest to what I’ve been liking. It is 6" 40 ILD under 3.5" 24 ILD. I think this is overkill for us(9.5" of latex) and our preference has been in a less stiff core (i.e. 32") which is why I think we are able to get away with a thinner comfort layer. Ultimately, something slightly softer than the Lago would have been ideal. The 24 ILD comfort layer is probably a tad to stiff, particularly over the 40 ILD base. How much difference a 22 ILD comfort layer would have been…I don’t know. Maybe 2" 22 ILD over 32 ILD would be the way to go since 2" 19 ILD over 32 ILD might have been a tad too soft.

The Essentia mattress line is really very interesting and way out of my budget. I tried it again today. It is solidly in the memory foam camp. Very different from latex although the comfort layers are made out of rubber tree sap (i.e. latex). They are 5.25 and 6.25 lbs density foams. The sales staff said that comparable tempur foams (density) take 40 seconds to recover whereas these take just 7 seconds. This is consistent with my sense that they don’t create the same cavity impression as tempur foam. For those who are close to one of their few North American outlets, I suggest you test it out. The NuForm beds at custom comfort were nothing similar to these. Totally different feel! I’ve ruled out trying to replicate an Esstentia bed.

I’m still thinking about what my next step should be…there’s just so much to consider. Thanks for all your help thus far.

9

Hi MikeM,

Just to add a few thoughts to the mix.

I find its easier to think of the wool as an interactive layer rather than a part of the ticking. Wool is a fiber that has some resilience (more than some and less than other animal fibers like horse hair or pig hair).

When the quilted wool is over soft latex like 19 ILD or less … then it will tend to “firm up” the latex because its not as soft or elastic as the latex. When it’s over firmer latex (like 24 - 28 ILD or more) then it will often create a feeling of being softer because it doesn’t “interfere” with the compression of the firmer latex as much and has its own “softness” and resilience. So the effect of wool depends to some degree on the firmness of the latex that is under it. Some people even like to sleep directly on firm latex like 32 or 36 ILD (shudder) and for them the wool would make the latex feel softer. Strangely enough … tall and thin people are often at the extremes of liking either really soft latex on top (to create a deeper cradle with their lighter weight) or really firm latex on top (because they like to be more on top of the mattress and don’t need as deep a cradle with their lighter weight for pressure relief).

The transition between layers is often a big part of what gives a mattress its properties. With a 2" comfort layer … the layer underneath become more noticeable and if the transition from soft to firm is too big, this can often be felt as uncomfortable. With a 2" layer … it’s usually better (certainly for side sleeping) if the ILD’s are closer together. 19 over 28 or 24 over 32 would give a smoother transition and when the lower layer is “needed” as part of the comfort layer … then this transition can play as big a role as the ILD’s themselves. If all of it is blended Talalay which has average ILD ranges of 19, 24, 28, 32, 36 … you would be looking at a transition of approximately 8-9 or 12 ILD. I would choose 8 over 12. To get ILD’s in between these … you would need to go to natural rather than blended.

No latex core is an “exact” ILD and the rating is an average of testing in 9 places in the core. The range from softest to firmest on the same core is usually in the range of 3 or 4 ILD. An ILD difference of about 4 is usually about the least that most people will even feel although it may make a difference over a longer time like overnight in terms of pressure relief and the overall performance of the mattress.

BTW … I talked with Chuck at Brooklyn Bedding a few days ago and asked him to pass a message on to John that I’d love to talk with him. We talked a fair bit and he told me that they are no longer using the quiltable latex but that they are now giving people the choice to use Talalay or natural Dunlop latex in their mattresses and you can choose the ILD’s. They are in a transitional phase and working on some stuff and this may be part of why I haven’t had the chance to talk with John. This was good news to hear.

Thought I’d add a few things to the mix that hopefully simplifies things a bit rather than makes them more complicated.

Phoenix

10

I had a “breakthrough” type experience today. I visited a store that carries savvy rest latex mattresses. The savvy rest mattress consists of 3, 3" layers of latex. The layers the store carried were firm, medium and soft in both Talalay and Dunlop. Consider the number of combinations that are possible. I was able to test out a myriad of combos and really feel the difference between Dunlop and Talalay.

For anyone interested in a latex mattress, try to find a savvy rest dealer. Even if you don’t buy one it will be a very rewarding experience. Phoenix’s biggest contribution to this forum–among MANY–is his urging prospective mattress customers to go out and test, test, test. There are simply to many permutations (dunlop, latex, soft, firm, medium) and even slight differences in construction feel very different. So I offer a big “thank you” to Phoenix for his suggestion to test many different constructions to understand the differences.

To me, dunlop is more bouyant and lively than talalay. To me, with dunlop, you sleep “on” the mattress whereas with talalay it is a little more of a sleep “in” feel. This seemed to be exagerated when there was a more radical transition between layers or when the bottom layer was firm (instead of medium). This was counterintuitive to me because med/med/soft or even med/soft/soft did not feel as squishy (sleep “in”) as much as firm/med/soft.

I did like (from bottom to top):

  • firm (dunlop), medium (dunlop), soft (dunlop)
  • firm (talalay), medium (talalay), soft (talalay)
  • medium (dunlop), medium (dunlop), soft (talalay)

I did not like:

  • firm (dunlop), medium (dunlop), soft (talalay) - sank into the mattress too much
  • firm (dunlop), medium (dunlop), medium (dunlop)
11

Hi Mike,

Thank you so much for sharing your experiences with the forum. It is sometimes difficult to get across some of the seemingly counterintuitive ideas that are connected with latex layering and your experiences connected to the specific layerings that you outlined are really valuable.

In particular your experiences highlite the differences in feel between the two different types of quality latex and how different transitions and interactions between layers can affect the feel and properties of a mattress.

These two in particular …

  • medium (dunlop), medium (dunlop), soft (talalay) … which you liked
    and
  • firm (dunlop), medium (dunlop), soft (talalay) - sank into the mattress too much … which you didn’t like

shows how much of a difference even a “relatively small” change in the lowest layer can affect the feel or depth of cradle through what I call “the order of compression”. This “order of compression” affects how far you sink “in” to the top layer before it “firms up” enough to make the lower layers start to compress. Because the bottom layer was firm Dunlop … it would “hold firm” for longer and “force” the upper layers to compress more before it too started compressing under your weight and taking up the strain.

There is a great deal of technical “science” behind all of this as well as the “art form” of being able to visualize and experience how all the different types of layerings interact with each other and with different individuals.

Thank you again for your very valuable comments :slight_smile:

Phoenix

12

ILD Ranges communicated by Savvy Rest:

Soft Dunlop: 22-30

Medium Dunlop: 31-39

Firm Dunlop: 40 and above

Soft Talalay: Soft 20-24

Medium Talalay: Medium 30-34

Firm Talalay: Firm 35-40+

Now that I know the ILD ranges, it would seem consistent that we liked a med/med/soft (dunlop/dunlop/talalay) Savvy Rest combination since we also liked latex mattresses with a base of 32 ILD and not ones that were very firm (36-44 ILD).

If we go with 3, 3" layers then we’ll rule out the “firm” layers. Right now, I’m leaning towards med/med/soft.

Phoenix, how would two, 3" 32 ILD layers feel different from 1, 6" layer…both mattresses under, say, a 3" 22 ILD layer? 2 of the same ILD could be combined into a single 6" medium layer and probably be less expensive. OTOH, I don’t want to purchase something I haven’t tried.

The other combination I’d like to test more is med/soft/soft (dunlop/dunlop/talalay). I liked this when I tried it but my brain did not want to accept this as the ILD “numbers” would suggest that the mattress would be too soft. This combo actually did not feel as soft as firm/med/soft (dunlop, dunlop, talalay) and it it did not compress as much (i.e. sink in). One reason this combo lingers is because then I would have the flexibility of trying at home soft/med/soft and construct a double sided mattress. I did not try this combo in the store, but I think I’ll go back and try it next weekend.

My other questions are:

  • who provides the most affordable 100% natural dunlop layers in standard king and XL twin? (2 XL twins = king?)
  • if the latex is 100% natural dunlop, can one conclude that the quality will be about the same for different suppliers? Latexco, Latex Green, Dunlopillo, Coco Latex??
  • Who offers talatech and 100% natural talalay at the most affordable prices in the same dimensions?
  • is there a material difference in quality of the 100% natural talalay latex supplied by various suppliers? LI, Radium, etc?
13

Hi MikeM,

A single 6" layer would act slightly firmer (when it was compressed more deeply) than 2 x 3" layers. The difference would not be really significant and has to do with the slightly different internal forces (such as shear forces) and resistance between the two layerings. Multiple layering would be more noticeable in the comfort layer (such as 3 x 1" layers of 22 ILD vs 3" of 22 ILD with the multiple layers acting as a thinner/softer surface than the single layer). Bear in mind too that Dunlop has more variability in ILD across the surface than Talalay and also has a slightly “firmer” side and a slightly “softer” side which can also make a small difference. Trying to get to an exact ILD is usually not really possible although Talalay is usually more consistent and “closer” on average to a specific number.

Latex is somewhat unique because it gets firmer faster than other materials (Dunlop more than Talalay even) so a layer that is rated at a softer ILD with 25% compression can still be firm and supportive at a deeper compression. Having said that though … I would tend to be just a little wary with a soft dunlop under the soft Talalay as your hips may sink a little further down into the mattress than you would want for good alignment even though the sinking into the top layer for pressure relief was fine. Your personal testing though would be the most accurate way to know for sure.

There are several high quality Dunlop Latex manufacturers who make 100% natural Dunlop latex. The most common are Latex Green, Latexco, and CoCo Latex (Savvy Rest supplier) and Arpico. Latex Green and CoCo latex both produce organic latex as well (the same material as 100% natural latex but the latex cultivation and production methods have been certified as organic). There is currently no organic Talalay latex even though there is 100% natural Talalay. They all produce high quality molded Dunlop cores that are very comparable however different Dunlop producers will each have their “secrets” in their formulations and production methods. There are many other quality Dunlop producers besides these as well however these tend to be the most common.

This depends to some degree whether you are buying bare latex layers, the thickness of the layers, special pricing that may be in effect, and shipping costs if any. Often the lowest cost is from a local manufacturer who is willing to sell you a latex layer even though many of them are not set up to ship across the country so only supply locally. Sometimes some outlets may have specials with limited selection which may be less.

The better sources for latex layers of all types that I’m aware of are listed in the component post here.

In terms of buying a mattress as opposed to individual latex layers … There are so many different factors and preferences involved that are important to different people that a “price per inch of latex” comparison is fairly meaningless and the best value for any individual could be from any of the members of this site or others that aren’t depending on the features and choices and options that are part of what each person considers important in their idea of “value”.

There are other outlets that may have special pricing from time to time and there are also some online outlets that I don’t fully trust will ship you what you order (such as some on ebay or FBM) both of which may be “cheaper” but you take the risk of buying latex which is either the wrong material or the wrong ILD.

There are currently 2 primary manufacturers of Talalay latex which are Radium and Latex International. I consider both of these to be very high quality. There are also now Chinese and other Asian Talalay latex core producers (at least 3) … some of which may be appearing in mattresses in North America. I haven’t had enough feedback and they don’t have enough real life market experience to know how they compare, especially because most manufacturers are still using LI and Radium.

Hope this helps … and I’d be curious to hear about your experience with M(Dunlop) S(Dunlop) S(Talalay)

Phoenix

14

Hi Mike,

Just to add a little bit to the “theme” of post #11 …

One of the layerings you liked was - firm (talalay) … say 36 average, over medium (talalay) say 32 average, over soft (talalay) say 24 average.

You could create a construction that would provide similar pressure relief and a feeling of “sinking in” to the top layer slightly less but improving support of the hips with a construction like 2" of 24 Talalay over 3" of 28 Talalay over 4" of 40 Talalay. This way the top 3" of the mattress would be a little firmer on average (slightly shallower cradle) with pressure relief that would still likely be very similar but the bottom 6" would be a little firmer on average and keep your hips up higher. The feeling would be slightly less “in” the mattress (with other factors like ticking and quilting and base being equal).

This wider choice in ILD’s and layer thickness is often not available through more “standardized” online DIY outlets as they have to deal with "the “averages” of online purchases more but they are often available from custom manufacturers who can build your mattress any way you wish and from a few more specialized DIY outlets or through special orders. While this is “fine tuning” to a much larger degree and both would be great for a large majority of people … I just wanted to show how having a wider choice of ILD and layer thickness options can make a difference and use different layer thicknesses and different ILD’s to change one or more of the “feel” or pressure relief or support characteristics of a mattress while keeping the parts you like.

Of course for most people … the choices available with standardized layer thicknesses and ILD’s can create a mattress that is far superior than anything they would be likely to purchase otherwise … for some people these seemingly minor changes can make a significant difference.

Phoenix

15

Thanks Phoenix for your continued feedback and insights!

I contacted several latex manufacturers hoping to find local factories (I also called several that you referenced in one of your posts above).

Arparcio - they emailed me and directed me to LatexCo West (a competitor!)
LatexCo West - referred me to an outlet in West LA that sells foam. I’m not sure they have what I need
LI - didn’t respond
Latex Green - couldn’t find a way to contact them
Radium - no contact found

I did contact a helpful local factory that carries LatexCo. Any feedback on the quality of their Talalay relative to LI or Radium?

Back to the mattress cover. Ideally, I’d like to find a cover with quilting in the sides but no quilting on top. Bamboo or cotton or stretchy fabric. The quilting on the side would provide “form” to the mattress, especially if I use 6 layers of XL Twin. I’m concerned that an unquilted cover would result in a sloppy looking mattress.

I am open to trying custom thicknesses and ILDs but, unless I have a “breakthrough” and identify a factory that carries all this, I doubt I’ll go this route as I don’t feel comfortable purchasing a “mix” I have not tested since I’ve experienced different feels with very slight differences in construction. I would like to try 28 ILD in a middle layer. Based upon my experience to date, something as firm as 40 ILD concerns me but I have never tried lower ILD middle levels that might neutralize this X-firm bottom layer.

As far as “sinking in” I thought I would add that what I have not like as much is not so much the softness–for instance, the 2" 19 ILD on top of 6" 32 ILD on top of 19 ILD was soft but comfortable–but rather the feeling of “sinking in” due to the softness but the mattress enveloping the body where it is more difficult to turn over on one’s side and back again. This I experienced on the OMI Terra. One personal aspect I did not not mention is that I have a curvature of the spine that might be helpful to note (not a medical condition that requires attention or that results in back pain). If I lie flat on the floor I have more space than most people in the small of my back.

Thanks again!

16

Hi Mike,

Latex Green is an offshoot of Arpico who broke away from that company in Sri Lanka. They became very popular in North America and gained market share from Arpico. Sleep Comp carried Latex Green (they were a distributor for foam manufacturers) as well as Radium Talalay from the Netherlands. Latexco purchased Sleep Comp and Sleep Comp became Latexco West but they continued to supply latex of various types besides their own. Arpico seems now to be making a comeback and gaining market share back from Latex Green and of course it would be purchased from Sleep Comp (now Latexco West). That’s the short version but there are also many more back stories to all of this.

So Latexco produces Dunlop Latex (not Talalay) and also distributes latex from other companies including Radium Talalay. They tend to deal only with manufacturers and are not always so forthcoming with consumer inquiries. LI does pretty well with phone enquiries in my experience and in the mattress industry, this seems to be the norm. There are members of this site who get most of their Talalay from LI while others get most of their Talalay from Radium (through Latexco/Sleep Comp) and this will switch from time to time based on economics and other factors as all of them could order from whichever they choose.

In terms of Talalay, both Radium and LI are very high quality. There are some manufacturers who prefer one over the other for various reasons but in general you will do well with either. There is Asian Talalay now beginning to come into North America which is being produced by factories which produce to western standards but at the moment there is little specific feedback in terms of its relative quality even from the manufacturers who know about it (and many don’t). This is a very “political” industry with alliances that are constantly being formed and reformed between various foam pourers, distributors, and manufacturers and constant efforts to gain market share while protecting what they already have.

In terms of Dunlop latex … Arpico, Latex Green, Latexco, Coco Latex and quite a few others are all very comparable in terms of quality and each can produce quality Dunlop latex.

While there are companies that produce ticking in any way that is desired … they supply wholesale to manufacturers (who want to differentiate themselves from others) and most of the consumer zip covers are fairly standardized. I seriously doubt that you will find a zip ticking which is quilted on the sides and not the top as the economics of this would likely put it out of the market. A zip ticking that fits correctly is usually fine and the resulting mattress is not “sloppy looking” IMO.

I understand the preference for being “on” the mattress and the sense of freedom of movement that it provides. I personally loved the feel of the OMI and the ultra soft top sculpted layer which is effectively much softer because of the sculpting. It’s actually (in its standard configuration) 25 ILD over 35 ILD over 25 ILD and then the topper is 25 ILD as well but because its convoluted it acts much softer (probably well under 19). The “order of compression” has a lot to do with this in terms of how the firmness of each layer affects the compression of the others. A 4 inch layer for example that has a sag factor of 4 and an ILD of 20 will take 20 lbs of pressure to compress 1" but 80 lbs of pressure to compress 3". Long before it compresses even 3", a 40 ILD layer underneath it will start to take up the strain and compress. This relative ILD and sag factor is a big part of how deeply each layer including the top one will compress and how much of the strain it will take up before the body “comes to rest” in the mattress when all the many forces come into an equilibrium.

I would tend to lean towards a 2" comfort layer given what you have shared and your lighter weight and I particularly think that zoning may help you fine tune this to allow your shoulders to sink in deeper while staying firmer under the hips. It would be very interesting if you were to call one of our members http://www.customsleepdesign.com/ and talk with Bob and tell him your preferences and “issues” (including any budget issues so he knows you prefer a 9" version of what he normally sells as an 11" mattress) then go through the measuring exercise to see what kind of zoning recommendation he comes up with for you. It may be very helpful. He used to be a VP of Latex International before he decided to start making mattresses.

Phoenix

17

Phoenix, I just found your “Quick Find” menu for the first time. Just a suggestion, it’s tucked below the top fold on your home page…I had to scroll down to even see it. There’s such valuable content located there that you might consider moving the section up so it’s visible on the top fold of your homepage.

Reading through your section on “stats”, I took a few measurements. Lying on a carpeted floor, I was able to stick a credit card lengthwise under the small of my back (I have a slight swayback). It measures 2 1/4". The measurement from the outside of my shoulder to the outside of my chest is 3+“. I’m a back and side-sleeper. My spouse is curvy and a side sleeper so she’s in the same boat. Would we be correct to conclude that a 3” comfort layer if using differential construction or a 2" top layer (or even 3") and 28-32 ILD middle layer using progressive construction would be in order?

Finally, if one is sleeping on one’s back and finds it comfortable to tuck a pillow under one’s knees, what does this suggest about the current mattress? Also, my spouse will do the same when lying on her side. Any feedback is appreciated, as always!

18

Hi MikeM,

Thanks for the website feedback. The reason I put the quickfind menu lower on the main page is because I wanted the picture and some content to show for a first visit to the website homepage. The links are the same as the menu bar on the top of the main page (which can be accessed without scrolling) except the quickfind is organized more by topic rather than by section so the rationale was on the home page that they would click at least one of the top links and on all the other pages of the site the quick find is available without scrolling. The forum is the other exception to this as it also has the top menu bar to all the site content but I wanted the forum thread titles to show rather than the quickfind. I was debating whether to put the quickfind where the picture is on the homepage but for the home page I decided in the end to put the picture on the top because the menu bar had the same content anyway and one click would take them to pages where the quickfind was more easily visible. Over the next few months there will be quite a few additions to the site and I may reorganize the content somewhat based on feedback and experience so I certainly appreciate the feedback.

Your stats are “in the range” of normal and they are part of the reason why 3" for side sleepers and 2" for back sleepers are a good starting point. Part of the difficulty of being specific is because there are many interacting factors involved and each layer doesn’t fully compress before the next layer takes up the strain … even in a differential construction. People also don’t sleep in an “exact” position as there are varying degrees of half and half positions (such as on the side but a bit towards the stomach with the top knee raised and on the mattress). Your conclusions though are “in the range” of what I would suggest and I have to say I’m impressed that your “translations” of the information on the site were so accurate … subject to confirmation with testing. Part of the variables would be the ILD of the comfort layer and the support layer under it as they interact together and a firmer comfort layer will take up more of the compression before the layer underneath kicks in but in general you are correct.

The biggest reason zoning can be so helpful is that it helps to solve the wider/lighter shoulders issues for people who spend time on their sides without using an ILD which is too soft for the best hip alignment. While I think that it certainly is more accurate for most side sleepers … layering without zoning especially with latex which has a different progressive compression rate than most foams is usually fine for most … even if they would have additional benefit with zoning. Its all a matter of tradeoffs and of course that sometimes includes “is this benefit worth a little extra cost”.

A pillow under the knees can compensate for hips that are sinking too far and straining the lower lumbar as it rotates the pelvis up when it is sinking too far. This can come from a construction where the hips are sinking in too far although it is often a good idea anyway as it does no harm and can often help as all people carry more weight in their hips than their shoulders. Pillows between the knees (one knee on top of the other) on the side can help the upper hip joint from feeling strain as because raising the top leg can help relieve pressure on the hip joint. When people sleep on their side with the top leg forward and bent (a little towards a stomach position), then a pillow between the upper knee and the mattress (rather than between the knees) can also relieve pressure on the upper hip joint. A pillow under the lower knee while on the side would in most cases be counterproductive as it would increase the pressure on the hip joint (it would cause a bigger sideways angle in the joint). If this is what she is doing … then it would likely be an attempt to compensate for something else such as a pressure point or top hip joint misalignment in a “less than optimal” way. This would be like a muscle being tensed to compensate for another that was injured or sensitive.

Thanks again for your questions and feedback

Phoenix

19

Hi Phoenix

Zoning. I’d like to explore zoning a little more. I do sleep with a pillow under my knees when sleeping on my back. I think this helps compensate for my swayback, helping the small of my back lie flatter on the mattress. So it might be helpful to address this with zoning. I reread your posts and I see how pressure can be taken off the shoulders if the hips are allowed to sink in…so it’s a tricky balance. Arizona Mattress is advertising a 7-zone dunlop soft (21-25 ILD) topper (latexco). I’ve read your FAQ about zoning suggesting that more than 3 is suboptimal and 2 is often best. I suspect that the zoning in this soft topper may not provide enough stability for the hips (i.e. mixing a sufficiently higher ILD in the hip area with 22ish in the shoulders)?

In your progressive construction…2" 24, 3" 28 over 4" 40 ILD…how critical is the 4" layer? Could it be 3 inches since this is probably a more widely available thickness?

I have had good luck with a 1.1" top layer of 19 ILD. Instead of going with 5.5" of 32 underneath with 1" of 19 ILD on the bottom (double sided), I wonder how 1.1" 19 over 1 or 2" of 28 ILD over 5.5 of say 36 ILD would be? Any better or worse support for the hips? As a reference on thought the OMI Lago (3.5" 24 ILD over 6" of 40 ILD was maybe a little firm. As another reference, I’ve tried 2" of soft talalay (ILD unknown) over 6" of firm (36-40 ILD) talalay and this was too firm.

I’ll try contact Bob about a custom 9" design but I suspect the price will be more than I want to pay. I did find a local foam shop that carries blended talalay (via Sleep Comp) but his prices were higher than SleepEZ. I am awaiting prices on blended talalay from a local factory who seemed willing to customize to my specifications. Thanks ~ Mike

20

Hi MikeM,

This is very true … if the top layers are soft and thick enough for the shoulders to sink in … that same ILD or layer combination will often allow the hips to sink in too far. The variable here is the weight vs the surface area of the different parts of each body and this varies with each person and with different sleeping positions. On the side for example … the shoulders are lighter and wider but have less surface area (are more pointy) so if a material has the right qualities (ILD, sag factor, and point elasticity) then a unizone is often enough. With lower quality materials or with more difficult body weight distributions or sleeping combinations … then zoning can be important. Foams with a high sag factor are in effect a form of zoning as deeper compression creates a firmer zone more than foams with a lower sag factor.

I do believe that 7 zones can sometimes be overkill as the main areas that can benefit with zoning are the balance between the hips/pelvis, the lower back, and the shoulder areas. The differences in the other areas of the body don’t really require zoning except in more extreme circumstances. The issue with the 7 zone as well is that the zones don’t really have much of a difference and the differences themselves are often less than the normal ILD difference over the surface of the material itself. Talalay latex can have an ILD difference of about 5 over the surface of the layer while the variability of Dunlop can be even more so a zoned core that only has a difference of 4-6 ILD doesn’t make much difference … although sometimes even small differences can help.

Zoning in the lower layers of a mattress are primarily designed to hold up the hips and pelvis and this is the reason that zoned innersprings with a firmer middle third is so common (3 zone with a firmer middle). Zoning in the upper layers is primarily designed to allow the shoulders to sink in further both for pressure relief and for alignment and this normally only requires a softer upper third (2 zone with a softer upper third). Of course because the layers interact, each type of zoning will have a secondary effect on the other layers. If a top layer is also zoned … it can add to the effect of zoning the lower layer as long as the firmer zone under the hips is still soft enough for pressure relief for the hips. For example if an upper layer of say 3" was zoned 19 ILD in the upper and lower third and 32 in the middle … it would certainly affect how deeply the hips sank in but may be too firm for some for good hip pressure relief (which comes from the upper layers of the mattress). An upper layer zone of 19 in the upper and lower third and 24 in the hips would likely still provide good pressure relief for the hips but the difference is so small that the natural variation of the material may be bigger than the zoning itself. Small differences like this may help and “add up” with other design factors but by themselves the difference would be small.

Changing the layer thickness of a bottom layer by an inch would act in a similar way to increasing its firmness. With a thinner bottom layer … it will have less room to compress and will firm up faster and “force” the layers above it to compress slightly more. I might even be tempted to go with 32 in the middle which would make it similar to the Savvy Rest except with a thinner top layer (2" instead of 3") and a slightly firmer base layer. If this thinner top layer still provided adequate pressure relief and allowed the shoulders to sink in far enough … it would certainly be better for alignment in your other ppositions (my “rule” for combination sleepers is to use the thinnest firmest upper layers that provide good pressure relief on the side). Bear in mind though that ILD changes of 4 or less are more about fine tuning here than dramatic effects. Changing the top layer thickness will have a bigger overall effect.

Having only an inch of 19 over a firmer layer can present an issue for some with the transition between them when they are on their side, particularly with lighter weights who will feel the 28 ILD as firmer. Even lighter weights will “go through” the 19 ILD easily and then feel the firmer 28 underneath it (or the layers below that if it was only 1" thick" as well) more than is comfortable even though it may be good for alignment on your back or stomach. I would certainly spend some time on my side with this construction to make sure I wasn’t feeling any strain or pressure on my hips.

2" of 28 under the 1.1" 19 ILD top layer would likely be better for pressure relief (than 1.1" over 32) and the support would likely be similar (softer transition with a firmer core). This may still be too firm for you though in terms of pressure. The thinner the layer on top … the more the qualities of the next layer down come into play and the closer together the ILD’s normally need to be. This is somewhat confirmed with your experience with the Lago which had 3.5" of 24 on top which was too firm. 1" of 19 over 2" of 28 ILD would be less pressure relieving for most (but not all) people. Any difference in ticking/quilting will also play a role here as well (either softening up or firming up the upper layers).

It’s difficult to make a comment about the “unknown” talalay as the ILD would be an important part of why this didn’t work. If you bought it from certain inexpensive outlets … it may not be talalay at all or if it is, it may be cut from a firmer core and then only labelled as soft on the “marketing theory” that its OK to label it with a lower ILD because the layer is thinner. If it really was soft talalay however (cut from a 24 ILD 6" core) … it confirms that the transition between its ILD and the 36 - 40 core is too much (you are feeling too much of the 36 - 40). Where it felt too firm (shoulders or hips) would make a difference though.

Overall … there are so many subtle variations in each persons shape, weight, and sleeping positions that change the weight to surface area ratio with different depths of compression … it is difficult to “theorize” about what is best in more than general terms with “theory at a distance” and personal experience always becomes more accurate. Sometimes too … a deeper analysis can create a focus on the smaller details at the expense of the larger picture (even though I personally really enjoy the more detailed stuff). At this level of analysis … almost anything that is “in the range” would be better than what most people would end up purchasing. Going from 80% great to 95% great is where the devil is in the interacting details :slight_smile:

I would think though that given your stats and experience that a 2" top layer would be better than 1" for pressure relief and allow for a firmer transition layer (better for alignment) underneath it without sacrificing pressure relief. This could then have a much firmer bottom layer under it for alignment as well as this would not affect pressure relief to any real degree (even though it can affect the subjective feeling of softness or firmness).

Of course more “radical” zoning than what is built in to a core allows for a lot more flexibility in design and changes the picture much more than the smaller zoning variations built in to a core. I’d be very interested in hearing what Bob had to say in his recommendations. NOTE ADDED: for those that are reading this since it was written … Custom Sleep Design is no longer in business.

Phoenix

21

Phoenix, thanks to your help I feel like I’m getting close to a decision. In addition to the Custom Comfort, Electropedic, OMI and Savvy Rest, I’ve now also tried Pure Latex Bliss (Beautiful, Nature and Pamper + Topper).

The Beautiful was luxuriously comfortable, but my hips sunk in too much to the point of hammocking. So that’s out.

The Nature was definitely in the zone of what I’ll ultimately purchase. Good hip support. If there was any complaint, perhaps I could have used a tad more pressure relief on my shoulders while lying on my back. They also carried an Electropedic (1" 19 over 6" of 32 ILD) which also provided good hip support but even less pressure relief for the upper back than the Nature. It was very helpful to have these mattresses available in the same store (Beds Etc in Torrance).

Next, I tried the Pamper with a 3" 14 ILD topper. This was very comfortable and provided more pressure relief compared to the Nature (with less hammocking compared to the Beautiful). I then tried the 2" topper (14 ILD) and this was better, and closer to the Nature but providing better pressure relief through the shoulders.

I’ll stop here and make one comment for the benefit of other members. For those with back trouble, we’ve all heard that firmer is better…at least I have. This is a long standing perception. After reading Phoenix’s site closer, I now realize that a softer feel in the comfort layer will not compromise spinal alignment provided the support layer is sufficiently firm. I think I’ve now internalized this. Consequently, my desired mattress feel has changed since I started my search…not dramatically but I am considering a softer comfort layer. I just hope that I don’t go too far over concern that I select wrong after sleeping on it for a few weeks.

Back to the analysis. I wish they had the Nutrition as that seems positioned in between the Beautiful and Nature. Without having experienced it, perhaps the Pamper plus 2" 14 ILD topper was best.

2" 14 ILD
1" 19 ILD
6" 40 ILD

As a reference point, the OMI Lago was comfortable but perhaps a little firm. Lago: 3.5" 24 ILD over 6" 40 ILD.

The Pamper plus Topper is still pretty much differential construction and I wonder if a more progressive construction would be better? If so, I don’t know whether to tweak the Nature or tweak the Pamper plus 2" topper in building my mattress. If the Nature was slightly too firm across the shoulders, that makes me think that a 2" 14 ILD top layer might be a good starting point. A 6" 40 ILD or 36 ILD base is also probable. That leaves the middle layer as a question mark…and a tricky one as I would like to balance the need for hip support versus pressure relief for the shoulders. I would like to be under $1,800 for King and I feel I could probably accomplish this at mattresses.net.

So maybe:

2.0" 14 ILD
2.0" 24 ILD
5.5" 40 ILD

– or –

2.0" 14 ILD
2.0" 28 ILD
5.5" 40 ILD

I know that the first one would provide more pressure relief than the OMI Lago (3.5" 24 ILD over 6" 40 ILD).
and hopefully less versus the PLB Beautiful but I am uncertain because the top 4" is actually softer. Again, the Beautiful was too soft and I want to avoid replicating it while providing more comfort than the Nature. I don’t know how the 2nd configuration would feel.

I presume that both would provide slightly more pressure relief than the PLB Nature that I tried. The first configuration would probably be the closest to the Pamper + 2" topper with the 2nd config being slightly less pressure relieving?

I’m a little surprised that I am considering a 14 ILD top layer, but I started my posts on this site initially liking the myessentiia line which has natural memory foam top layer (similar in feel to memory foam) over firm dunlop…so I guess I shouldn’t be that surprised.

Regardless, I’m leaning toward a stretchy non-quilted ticking for mattress cover and a thin waterproof non-quilted mattress pad.

Any guidance would be appreciated!

22

Hi MikeM,

You’ve been testing some very nice mattresses … and I’m impressed too at the accuracy of your feedback! You really have zoned in on and recognized the many differences in ILD, layer thicknesses, and progressions.

As you mentioned … the Pamper with the 2" topper would be a more pure differential construction with 3" of soft over a firm core with no “transition” layer. The Nature is also tending towards differential with only a 1" transition layer and in effect this meant that your top 3" were too firm overall. It’s too bad that the Nutrition wasn’t available as I think it may have been very close with the extra inch of 28 ILD in the middle.

Given your feedback (including with the savvy rest) and the slightly changing preferences from the beginning to now as you became more accustomed to the idea of a softer thicker comfort layer … I’m thinking (ironically) that the Nutrition is the construction I would be shooting for. While I certainly understand how nice the 14 feels, the Beautiful also felt very good to you with 3" of 19 ILD on top in terms of pressure relief and so did 3" of softer talalay with the savvy rest so I’d be tending towards 19 over 14 for that reason.

Your “critical zone” seems to be about 3" or less. In other words … with 3" of soft latex (2" 14 and 1" 19) in the pamper you weren’t feeling the firmer 40 ILD core layer as a “hard” layer underneath. For this reason I would try to avoid more than 3" of latex of 24 or less for the sake of alignment. In other words I would want the 4th inch to be in a firmer range of 28 or higher. This means that

2.0" 14 ILD
2.0" 24 ILD
5.5" 40 ILD

Would probably be too much soft (4"). It would likely still allow your hips to sink in too far.

2.0" 14 ILD
2.0" 28 ILD
5.5" 40 ILD

Now the middle layer is more in a transition ILD range and more supportive in terms of keeping your hips up which is important. My only concern here would be in the difference between the 14 and the 28 which may not be a gradual enough transition which could lead to feeling the “firmness” of the 28 more. I’d probably tend towards 2" of 19 on top … which would bring us to the Nutrition construction. This would be my preference of the two that included the 2" of 14 ILD but I would be just a little worried that 2" of 14 would allow me to feel the 28 a little more than I would want.

I read the entire thread to look at all your preferences in each testing experience relative to what else you tried that day. Then I laid down and closed my eyes and tried to “feel” the different constructions as if I was you. My “gut” and my instinct to go slightly firmer in the face of uncertainty told me that 19 was likely “better” way to go. You have had enough experience and are looking at your results accurately enough that I would trust your instinct over my gut though :slight_smile:

As far as the ticking and the protector … I would do the same.

Phoenix

23

Thanks Phoenix for your continued helpful feedback. So I found the PLB Nutrition in LA. Relative to the Nature, the Nutrition has 1" more of 28 ILD in the middle layer sandwiched between 2" 19 ILD and 6" 36 ILD. I thought that this was going to be the “ticket” since I was seeking the same hip/lumbar support provided by the Nature with more pressure relief under the shoulders. I’m glad I tested it, and it just goes to show how very minor differences in construction can result in meaningful changes in feel and support. While lying on my back, my hips sank down just a little too much. Surprisingly, I did not feel materially better pressure relief under the shoulders so, all said, this might have been a step down from the Nature which provided better hip support. My spouse is far less interested in the mattress search but found she sank down too much but liked it generally. The store also had the Pamper plus Topper and we both agreed we were in mattress heaven. The combo we think would work:

2" 14 ILD
1" 19 ILD (or, alternatively, 22 or 24 ILD)
5.5" 40 ILD (blended talalay or dunlop)

There must be one or few things going on. Either the 40 ILD base is providing materially better hip support for me, or the 3" comfort layer (instead of 4") is also somehow helping to support my hips. The 3" combo of 14 and 19 ILD are also providing significantly better pressure relief under my shoulders. I’ve come to believe that my mild curvature of the spine (kyphosis) has rendered firmer support layers less pressure relieving for my mid-upper back and shoulders. My wife loved this mattress and would have bought it on the spot. She felt that it provided better support (did not sink down) but a luxurious soft feel on top.

In constructing a DIY mattress that captures the spirit of what we tried, I have a few questions on which I’d appreciate your guidance:

  1. Comfort layer. I agree with your post above in which you caution against more than 3" of softer foam (24 ILD or less). This is consistent with my field testing. Given that we were testing a PLB 2" 14 ILD topper (with non-qulted ticking), must I compensate for this when just adding the 2" 14 ILD raw layer inside the DIY mattress cover? I’m also leaning towards a stretchy non-quilted zippered cover. Assuming we’d like to replicate the pamper plus 2" 14 ILD topper, could I just order 2" 14 ILD, 1" 19 ILD and 5.5" 40 ILD and expect a comparable feel?

  2. Support layer. Given that we are leaning towards differential construction with a big ILD transition, would there be any material benefit from going with L.I. or Radium blended Talalay versus 100% natural dunlop for the core support layer? The OMI Lago (see comment below) has a dunlop support core with talalay on top whereas the PLB is Talalay top to bottom.

  3. Middle layer. Part of me says why mess with perfection and just go with 1" 19 ILD…just like the Pamper. Alternatively, we could try 1" of 22 or 24 ILD. I’d hesitate to go all the way to 28 ILD. As a reference point, the OMI Lago with 3.5" 24 ILD over 6" of 40 ILD is definitely in the zone of what we like. I tried it again today just to try to keep things straight in my mind and it provided good support through the hips and decent pressure relief. The Terra provided better pressure relief through the shoulders but not enough support in the hips/lumbar. If I were to stray from the exact layering in the Pamper plus 2" Topper it would like be in this middle layer. I would probably stick with 1" as anything north of 3" (in aggregate comfort layer) has been challenging to this point (with the exception of the OMI Lago). The 19 ILD is probably helping me to not bottom out on the top 2" 14 ILD (as I might if it were something firmer like 28 ILD). I do wonder what changes we could expect if we were to go with 22 or 24 ILD, and whether this would be a wise move. On the plus side, it would provide some hedge if, after a few weeks of trial, we decided to change from 14 ILD to 19-24 ILD for the entire comfort layer. On the other hand, I know how minute tweaks can result in a totally different feel. Thoughts?

I realize there are two other ways to go. Custom Sleep Design being one, or tweaking the bottom layer so that it was less than ~6" of 40 ILD and instead add a progressive construction with some portion of 40 ILD and some portion of 32 ILD (or thereabouts) and then increasing the ILD of the top layer marginally from 14 to 19-24 ILD. The challenge with either of these approaches, is that I’ll never be able to field test either one. If I was in CT, I could experience the custom design and probably go in that direction…but I live in LA. At one point, you had suggestion 2" 24, 3" 28-32 and 4" 40 ILD…and I bet that is very close to what I’ve been gravitating towards.

I think I am pretty much there but would like to run this by you for any final thoughts. I’ve gone on 8 separate field tests having tried custom comfort, eletropedic, savvy rest, OMI, pure latex bliss and I must admit that it was not until the 7th trip that I felt I truly started to distinguish the nuances of hip, lumbar and shoulder support and pressure relief. Thanks for steering me in the right direction and for the wonderful education!

24

Hi MikeM,

This too is very helpful feedback :slight_smile:

What is likely happening with the Nutrition that is different than the Nature is that with an extra inch of 28 ILD … the 5th inch down is softer and takes up more of the compression than with the Nature where the 5th inch is 36 ILD. The firmer 5th inch would “force” the upper layers to compress slightly more. This would result in either very similar pressure relief or in some cases better pressure relief depending on where inside the mattress the part of the body that was experiencing pressure came to rest. It would also be more supportive than having a 5th inch at a lower ILD and a slightly thicker mattress overall.

I certainly agree with you that having a 40 ILD support layer and a differential construction seems to be much closer than a progressive construction and that your “effective” comfort layer is the top 3" of the mattress. Using more soft latex than this would decrease support as the heavier parts of the body would have further to travel before they were “stopped” by the firmer layers underneath while the lighter parts would still be “stopped” above the support layer. So as you mentioned the better support came from both the ILD of the layer immediately below the top 3" and from the fact that the comfort layer was thinner … but still within the critical thickness range that seems to work best for you). This type of differential construction is for many people very comfortable as it is a very pleasing combination of soft and firm that can work very well. The trick here is that you are not “going through” the 3" and feeling the very firm layer underneath too quickly. A heavier person would feel more of the 40 ILD layer and for them it may not be so comfortable and they may need to “firm up” or “thicken up” the upper layers to prevent an uncomfortable transition.

So I would tend to work towards a similar construction with similar ILD’s. The only difference may be that 3" of 19 may need to be a special order (soft is usually in the low 20’s for DIY orders). An “exact” duplicate of 2" of 14 and 1" of 19 would normally be outside the range of “standard” layer thicknesses and ILD’s in a DIY mattress and would be a “custom build” which could increase the cost or restrict the layer exchange possibilities over a DIY construction.

An example of a progressive construction equivalent would use 2" of 19 ILD Talalay over a 6" layer of 24 ILD Dunlop.

The very very rough and simplified math of this would be as follows …

If a 6" layer of Dunlop takes 24 lbs to compress it 1.5" (25%), then using a linear progression rate from 0" to 1.5" it would take about 16 lbs to compress it only 1". This would give you a top 3" of roughly the same ILD as the talalay topper over the Pamper.

If the 5.5" talalay layer underneath the Pamper “blueprint” takes 40 lbs to compress 1.4" (25%) … then compressing the 6" of 24 ILD Dunlop underneath it another 1.4" (for a total of 2.4") would take another 42 lbs (assuming a compression modulus of 4.0 and assuming that the compression rate from 1" to 2.4" of compression is linear). This means that you would “in effect” have a very similar top 3" and a very similar top 4.4" and any compression beyond that would be firmer with the 2" 19 ILD talalay over 6" of 24 ILD Dunlop than it would with the Pamper. Bear in mind that the different materials and the other variables involved would not result in the exact same feel but it would be close in terms of both pressure relief and support.

If you were to use a 2" layer of 19 ILD talalay over a 5.5" talalay core of the same 24 ILD … your top 3" would be very very slightly firmer (insignificant) but the next 1.4" of compression would only be an additional 31 lbs (not as firm as the Dunlop) and the difference would become more with deeper compression. This is using a Talalay compression modulus of 3 as opposed to 4 for Dunlop.

A 2" layer of 19 ILD talalay over 5.5" of 32 ILD talalay would give you a firmer top 3" (the top inch of the talalay core would be about 23 ILD) and the next 1.4" would be about 41. This would be roughly the same in the support core but slightly firmer in the top 3" comfort layer.

I personally would tend towards a close equivalent to the known construction which would be 3" of 19 ILD over 5.5" of firm or extra firm talalay (I would tend towards a 3" layer of 19 ILD over a 3" layer of firm over a 3" layer of extra firm in a 3x3 construction). This comfort layer is a little firmer than 2" of 14 ILD and an inch of 19 ILD but is the closest equivalent in a single ILD 3" layer and I tend to err very slightly on the firm side when in doubt.

As you can see … there are many ways to get to a similar end using different layers, ILD,s and layer thicknesses. Bear in mind too that the ticking will also play a role and with these duplicates I would use a stretchy unquilted cover or if you go with a wool quilted cover you would need to fine tune the layering to take this into account.

To your specific questions …

You could order this but this would take you out of the realm of a DIY construction which uses standardized layer thicknesses and standardized ILD’s. This would be more of a complete custom build which would generally increase the cost. You would be getting into a fire barrier used without wool and the prototypes they have tested and can build within.

The biggest difference between Talalay and Dunlop is in the support factor as outlined earlier in this post. Different types of latex used in the comfort or support layers of the mattress will certainly affect both the feel and progressive perormance of the mattress. Bear in mind too that there are different manufacturers of Dunlop so I have only used a compression modulus (support factor) of 4 to illustrate the differences. This number is not exact between different types and manufacturers of Dunlop.

I would also stick with what you have tested for and wouldn’t go much firmer than 19 equivalent in the top 3" (however it was made up). While 3" of 19 is a little firmer than what you tested with the topper over the pamper … it wouldn’t be much. Going slightly firmer may help alignment more … particularly with stomach sleeping. Did your spouse test the topper over the Pamper on her stomach for a while (10 or 15 minutes completely relaxed)? My biggest concern would that for her the comfort layer was soft and thick enough to allow her hips to sink in a little too far on her stomach even though it would feel great on her side.

This was a little complex and “mathematical” post but hopefully it helped in pointing to how differences from the Pamper/topper prototype and material differences can alter how the final product performs. The closer you can get to the actual prototype you tested within the limits of a DIY construction … the closer to a similar performance and feel you will be. “Translations” into different layering or materials can also get close (or may even be an improvement) but because translations can be so complex and have so many variables, the closer to the “best” prototype you can get the more confidence you can have that it will be similar in real life.

Phoenix

25

That’s downright scary…I tried a similar combination at electopedic (see post #6) but the core was 24 ILD Talalay instead of Dunlop. I understand the Dunlop would be slightly firmer but I jack-knifed on that bed.

OK, I understand this math. You are trying to back into the Dunlop ILD rating that would result in ~14-16 ILD for the top 1" of the core layer so that, when combined with a 2" 14 ILD topper, would approximate 16-19 ILD for the top 3" comfort layer. Thanks for the education…I see a “latex compression calculator” in this forum’s future!

You lost me. Understanding the math above would be helpful. I’m confused starting with “underneath it”…underneath what?

That’s interesting because that reminds me that I liked the 2" 19 ILD over 5.5" 32 ILD over 2" 19 ILD at Custom Comfort and Electropedic which both carried this construction. How would the addition of this bottom 2" of 19 ILD affect the pressure relief/support versus if it were not included in the design?

Perhaps I’ll go back to Savvy Rest and try a 3 layer design again…although I think there top layer is 20-24 ILD. It seems that the only online retailer that would allow me to duplicate the Pamper plus Topper exactly is Sleep Like a Bear based on what is advertised on the various retailer websites…although I’ll contact some of your sponsors to see if they can offer the layers.

Phoenix, in practice, have you experimented with a few different constructions (varying the ILDs and thicknessses of the layers) that arrive at the same math to see if they feel comparable? I’d be interested in your feedback.

26

Hi Mike,

Your questions give me a chance to get into another rather technical and analytical post … but the stuff at the end is probably the most important and brings the technical stuff back closer to real life :slight_smile:

The “underneath” meant the 6" of 24 ILD dunlop underneath the 2" of 19 ILD talalay in the alternative construction. I was still comparing the 2" of 19 ILD Talalay over 6" of 24 ILD dunlop to the Pamper + topper “close equivalent” (3" 19 ILD over 5.5" of 40 ILD talalay) but looking at the comparable firmness levels deeper into the mattresses as the two mattresses were compressed more deeply.

It would take 40 lbs of pressure to compress the 40 ILD talalay layer in the Pamper + topper equivalent to 25% of its thickness (1.4"). The equivalent depth of compression on the alternative 2" talalay over dunlop construction would need to compress the Dunlop another 1.4" more than the inch we have already “used” to add to the comfort layer. So I was looking at the theoretical ILD of each mattress when it was compressed 4.4". This would be 3" of 19 ILD talalay + 1.4" of 40 ILD talalay on the pamper equivalent. It would be 2" of 19 ILD talalay and 2.4" of 24 ILD dunlop on the alternative construction. The Dunlop would need to compress 2.4" in other words to get to the same depth of compression as the pamper equivalent would have if the 40 ILD talalay compressed 1.4".

Compressing the top inch of the dunlop was based on a “straight line” progressive compression rate from zero compression to its 25% ILD rating of 24 @ 1.5" compression. Since we were looking at the relative ILD @ 1" of compression … this would be 1/1.5 x 24 = 16 ILD.

Going deeper into the Dunlop as it continues to compress … I looked at the ILD @ 1.5" (24) and then using a compression modulus of 4, I calculated the ILD @ 65% (3.9") which would be 96 ILD (compression modulus is the ratio between 25% compression and 65% compression). This means that it would take 72 lbs of extra pressure (96 - 24) to compress the Dunlop an additional 2.4" (3.9 - 1.5). Assuming that this was also a linear compression rate, then each additional inch of compression beyond 1.5" would take 30 lbs (72 / 2.4). So to compress the Dunlop to 2.4" (the equivalent in this construction of the 40 ILD talalay in the pamper + topper compressing 1.4"), it would take 24 + (.9/2.4 x 72) = 51 lbs. (I just realized that the previous math was wrong and I used 41 lbs in the last post because I used .9/3.9 instead of .9/2.4).

So with 3" of 19 ILD talalay over 5.5" of 40 ILD Talalay … the ILD of the top 3" would be 19. The next 1.4" (25% of the support core) would have an ILD of 40.

With the 2" of Talalay over 6" of Dunlop … the top 3" of the mattress would have roughly the same effective ILD (2" of 19 + 1" of 16). The next 1.4 " would be firmer (51 ILD corrected from 41 ILD in the previous calculation) and as you sank even deeper into both mattresses the firmness of the 2" talalay over 6" dunlop version would increase even faster than the 3" talalay over 5.5" talalay version.

THIS IS IMPORTANT

There are several assumptions in these calculations which I used to be able to illustrate how different constructions could “get to” similar performance. In this example, the two mattresses were roughly the same in the top 3" but the second option would be firmer in its “support” performance. It would “stop” the hips sooner.

These assumptions and calculations are not accurate for several reasons. First the compression modulus I used in each case is roughly correct but both Talalay and Dunlop have variable compression moduli depending on the density and ILD of the material and it is not consistent from manufacturer to manufacturer or even from ILD to ILD. Second, compression modulus is also not “linear” and is actually a curve. Third and most important … the actual pressure applied to each area of a mattress is a function of weight applied over a certain surface area and with the infinite variations in the shape of the human body … and the variance in surface area with increasing depth of compression for each person … the actual compression of the mattress in each area of a body and the relative depth of compression to keep the spine in alignment varies with each person. The different layers also have an “order of compression” and the compression of each layer is not independent of the other layers. The layers all compress in a constantly varying ratio.

While in theory there would likely be an algorithm which could do these calculations … it would still not be as accurate as actual testing because even if the compression modulus and other specs of each layer was known and the performance curve of each spec could be plotted (compression modulus is only one variable and things like hysteresis would also have to be included), it would still not take into account the variables of the person. In addition to this, at this level of analysis, subjective factors can also overwhelm objective performance and these subjective factors can change over time and with mood, stress, surroundings, and many other things.

So the reason I wanted to go into so much detail was mainly to show how different layering schemes and materials can “duplicate” one area of a mattress but adjust other areas in several directions and to show why sometimes some seemingly very different constructions can “work” for the same person. I would never suggest that “rough math” like this could be used to actually choose a specific layering except by “pointing to” alterrnative possibilities. More than anything … I wanted to show why a little discussed spec like compression modulus (also called sag factor and comfort factor) can have just as big an influence on mattress performance as ILD and why ILD alone can be so misleading. This is also compounded by the fact that ILD is measured in different ways in different areas of the world and with different materials and by different manufacturers. There is no one consistent method that is used by all the different types of foam manufacturers.

In the end … I would stick as close to what I have tested that works as possible because even though alternatives may work well (or even better) … they are more of an unknown in terms of how they will perform in real life over the long term. We all have a wide range of mattresses that will work well and as long as we are “in the range” of our own unique tolerances to pressure and alignment, a mattress will work well. Going for the last degrees of “perfection” can sometimes move us away from what would work best.

Yes. I did a LOT of lie on mattress testing (and still do to a lesser extent) to compare theory with performance in real life. I got very good at being able to discern small differences between different constructions and discerning where these differences likely came from. I also spent a lot of time looking at patterns to make sure that what I was explaining wasn’t just an anomaly particular to a certain mattress. Of course this is a constant learning curve because the variables are infinite and every mattress spec isn’t known but the overall "“directions” of what certain changes are likely to create for different people are at least somewhat predictable in most cases.

Phoenix

27

Great post Phoenix. The math is thought-provoking. I’ve done even more testing and am at the point of gathering quotes.

I visited PJ’s Sleep Company which has an array of OMI latex mattresses as well as its own Dunlop-based brand. The visit reinforced my preference for the PLB 14 ILD topper over a firm layer (either Talalay or Dunlop). At PJ’s, they had a 6" Dunlop latex mattress rated 35-40 ILD as well as the same thickness in 30-35 ILD. They had both a 2" and 3" PLB topper. I was able to confirm that a 2" comfort layer in 14 ILD is not sufficiency thick over firm latex. The 3" topper was great, particularly over the 35-40 ILD rated Dunlop which provided slightly better hip support versus the one rated 30-35 ILD. The 2" topper over the 30-35 ILD rated core was OK, but not as good as the 3" topper over 35-40 ILD which felt comparable to the PLB Pamper plus 2" PLB topper (the Pamper itself having 1" 19 ILD over 6" 40 ILD Talalay).

The other great comparison I was able to make during this visit was quick evaluation of this bed versus the OMI Lago (3.5" 24 ILD Talalay over 6" 40 ILD Dunlop). This is a good mattress for me but does not provide the pressure reliief under the shoulders that the other option does in spades. The ultimate benefit of this trip confirmed that I would be able to simplify the mattress construction and just go with 2 layers (3" 14 ILD and 6" 38-40 ILD).

Today, I returned to Savvy Rest and although there are some good combinations, it has proven more complex/challenging to engineer 3, 3" layers with standard ILDs (soft, medium, firm) that provide good pressure relief under the shoulders without sacrificing good hip support. Most of these combinations are able to provide good hip support but lack the pressure relief qualities that the 14 ILD latex is able to accomplish for me. All in all, I think I’ve done adequate testing to make a safe decision.

I would appreciate your feedback on an appropriate foundation…better options that are available. I’ve looked at:

Forever Foundation (All steel)
http://www.wayfair.com/Forever-Foundations-Forever-Foundation-Steel-Mattress-Foundation-FEL1009.html

Power Stack Foundation (Note added later: this is a discontinued product)
from My Green Mattress Products

Wood construction like this (not a great review on Amazon)

Charles P Rogers Parsons Hardwood bed
http://www.charlesprogers.com/parsons-bamboo-platform-bed-p-502.html

The latter is closer to the ideal for us (lower profile but still 7-9" of storage, but I’m not sure about the use of upholstered decks?

Actually the most ideal foundation would be one that simply disappears under the mattress with legs recessed under the frame, but I have been unable to find this minimalist option…

Guidance on use of slats (i.e. Ikea) or something more solid (i.e. bunkie boards, or the “upholstered deck” in the Charels P. Rogers link above) would be helpful.

Our ultimate goals would be:

  • Approx 7" of space under the frame, but relatively lower profile
  • sturdy, no creaking (we have 3 year old twins that like to jump on our bed)
  • provide air circulation (if necessary) for the mattress and prevent moisture etc. - is a solid wood platform good/bad?
  • I’ve read that spacing for slats should not exceed a few inches

Any thoughts on some of the better foundation options that won’t break the bank would be appreciated!