additional comment: I also donât want the middle layer of talalay to be so close to the ILD of the 4 inch 35 ILD base foam that the base foam serves little purpose, if that makes any sense. Would 28-32 natural talalay (Radium) be just as firm as 35 ILD base foam. I know these questions may be impossible to answer due to all manufacturing processing and formulas of foam being different, but maybe a rough guess would be ok.
If I went with the medium 24-27 I would have somewhat of a safeguard, as I could use it over the soft as a top layer. However if I went with medium firm 28-32 and it was TOO firm, it most life would make a poor top layer given my affinity for a soft top layer. The only way to soften it would be adding a 1.5 inch topper of some sort. So many variables to considerâŚ
Hi gardenguy,
You are correct that there is no way for me to predict what you may or may not like for your new âtransitionâ layer, due the many variances and subjective nature of selecting comfort layers.
I would avoid attempting to get too detailed in using empirical numbers in attempting to predict what a mattress âmightâ feel like, as unless you are very experienced with mattress design and how different materials interact (which would be very few people), attempting to get too technical only serves to drive you further down the rabbit hole into paralysis analysis. I hesitant to provide too much extra information, as Iâm fearful of contributing to this and thus not being helpful to you, but I do understand your desire to learn, and you do have a reference already of some combinations.
With that in mind, hereâs how ILDs are measured and how polyfoam and latex ILDs are not directly relatable. In addition to this though, ILD is not the most reliable indicator of how soft or firm a layer will feel. Compression modulus is even more important because very few people actually sink into a layer exactly 25% and compression modulus is the rate at which a foam gets firmer as you compress it more. Latex has a higher compression modulus than polyfoam. Also, latex is very âpoint elasticâ which means that a smaller area can compress with less effect on or resistance from the surrounding area than polyfoam. This is much like the difference between pocket coils that act individually and innersprings that have helicals that join the springs together so that the compression of each spring will affect the springs around it which makes the spring stiffer. Latex also has a lower hysteresis (how much energy is absorbed) and conversely a higher resilience (how much energy it returns) than polyfoam so there are also factors that can make latex feel firmer depending on how much a specific layer is compressed in a mattress. Because of its unique qualities and ability to take on the shape of the person on it (point elasticity) it can feel softer and firmer at the same time and some will feel it as one or the other depending on what they are more sensitive to, their body type, sleeping position, and how they sink into the mattress.
Overall, I would tend to take step back and look at the big picture a bit. Youâve decided you like Talalay over Dunlop. If the 19 ILD Talalay on the polyfoam core felt good but you desired a bit more plushness, then with your size the 24-27 could be a good choice. If you were âfeeling throughâ the plush Talalay to the core, then the firmer Talalay at 28-32 would probably be a good choice, but I donât think this is what youâre describing (that combination would tend to result in a bit more âmediumishâ to âmedium-firmâ feel).
Thatâs about as âboiled downâ I can phrase it without getting into the weeds too much. I hope that helps you as you go through your decision-making process.
Phoenix
Thank you Phoenix, I appreciate the thoughts here. I did read that post about ILDâs, very interesting. Let me ask this if I may; in your estimation would a 23-27 âmediumâ Radium talalay layer, be very close to a soft 20 from SOL? If it has close to the same amount of âsinkâ when the two are paired in the final configuration, it may be too much sink for me. I thought I read in some of your posts that a soft dunlop is comparable to a talalay of 5 ILD points ahead of it. Maybe I am mistaken about this, if so I apologize.
My fear I suppose, is that the 19-22 radium talalay I have now, paired with the 23-27 medium that 247 mattresses is providing, is going to fall on the number 23. If my soft happened to land on 22, then there we have two layers with one point separating them, and I am stuck with 2 softs essentially. This is my dilemma. I donât want to have to send another layer back, but I also donât want to get the 28-32 and itâs as firm as my existing poly base foam. To be certain I need more give than my base foam provides. I suppose this is the risk in DIY.
I talked to the seller about this as well, and while they assure the medium will be firmer than the soft, there is no guarantee it will be firm enough. Ditto if I go for medium-firm, could be as unforgiving as my existing 19-22 soft talalay- 35 poly base.
I am just talking out loud here.
*thinking out loud
Hi gardenguy,
You should notice that it would feel slightly firmer, and also there will be more of a difference as I think you said you are going from a 2" layer to a 3" layer. Also, remember that a smaller ILD difference will be more noticeable between plush layers (lower ILDs) than firmer layers (firmer ILDs), as it will be a larger percentage difference.
Donât try to be too predictive with specifics in an area where there is no such thing. All ILDs are within ranges, and the overall comfort depends upon how all of the layers of the mattress work together. Only your own personal testing of configurations will determine if the layers work well for you, which is part of the overall DIY process.
ILDs donât work in this manner and are not something where you add up and divide or come up with averages. This is why many manufactures choose to describe the foam layers as âsoftâ or âmediumâ, as it eliminates the temptation of consumers to come up with exact specifications in a situation where none exist.
What this means in âreal lifeâ is that trying to predict how a mattress will feel and perform using only one of many âspecsâ or variables that are involved can be somewhat risky or misleading, and even the most experienced mattress designers that are familiar with and have a great deal of experience with all the many variables and specs that can affect the feel and performance of a mattress can often be surprised at what a mattress was âsupposedâ to feel like based on specs and what it âactuallyâ feels like in real life so in practical terms the only reliable way to know how any specific combination of materials and specs will feel like for you would be based on your own actual testing or personal experience. Specs can be a very rough guideline that can help you âfind the rangeâ but there are far too many unknowns and variables to use them to find the âbestâ combination or materials or components that would be suitable for any specific person with any degree of certainty.
I understand wanting to get everything right on the first or second attempt, but thatâs all part of the experimentation and fun of a DIY project. 
Phoenix
Phoenix, I wanted to thank you again for all your assistance, it has been greatly appreciated. Itâs true that I want to make as few of mistakes as possible, however I suppose the mistakes are the teachers in the long haul. I went with the 28 for the middle layer, hereâs hoping!
Hi gardenguy,
Youâre very welcome, and Iâm looking forward to learning about your new arrangement!
Phoenix
Hi Phoenix,
In anticipation of my eventual configuration and the desire to protect the latex layers for as long as possible but also feel the latex doing its magic, do you think this cover would protect it from the forces which seek to destroy it? Or would you go also put an allerzip waterproof mattress encasement over that? Maybe that is overkill, I donât know. To me just the mattress cover with stretch to it seemed ideal and I would avoid the mattress encasement and just use a waterproof pad on the top. Any suggestions would be appreciated.
gardenguy
Or is there something better out there? My main concern is preserving the feel of the mattress WHILE prolonging the lifespan.
Hi gardenguy,
All foams will need protection from the mechanical abrasive forces, outside added materials (body oils, skin cells, fluids, etc.) as well as protection from UV rays and oxidation. Most foams will already have anti-oxidants blended into them, but youâll still want to use a good covering. There are a myriad of mattress encasements available, with the most flexible generally being some sort of a cotton/polyester/viscose blended with something like elastin. These will interfere less with the point elasticity of your very soft latex later.
Youâll always want a good mattress cover for protection from wear and âthe elementsâ, as well as helping to hold the materials together. DIYNaturalBedding had some interesting comments a few years ago about some of their latex samples and noted that the latex using a double wool batting and cotton cover showed the least amount of discoloration, followed by their latex using a single layer of wool with a cotton cover. Both showed minimal discoloration (some of which of course is normal). Of course your mattress will also have a mattress pad, fitted sheet, flat sheet, blanket and comforter upon it during the day as well. Iâm not familiar with the encasement youâre describing, but maybe someone here on the forum here is and can provide you some feedback.
If you want to look at some other options, you may wish to look at some of the cover suppliers listed in the component post here.
Phoenix
Thank you Phoenix, that is very helpful! I am looking around at the various links to covers. Just so I understand correctly, the mattress could benefit from a waterproof pad on top, but the latex still needs to breath correct? My thoughts were to order a cotton blend cover and a separate waterproof pad for the top only. I see some encasements made of a thin plastic(?) ,which waterproof the entire bed. Is that necessarily better with latex in regards to preserving longevity? I am thinking the answer will be no, since you just referred to a cover of wool and cotton, both of which are very breathable.
Some of the covers I am interested in have measurements of 38" by 74". The problem being my layers are 38" by 75". I am doubting the lack of an inch will be a big issue? I would think cotton-polyester would stretch. Maybe if someone out there has experienced this, they could chime in. Thank you very much!
Hi gardenguy,
You can read more about mattress protectors in post #89 here, and here. A polyurethane film for the upper layer would generally be preferable over plastic, as the polyurethane film will allow for some breathability and be more flexible that the plastic, but still be waterproof.
As for the dimensions, both your cover and your latex will have some âgiveâ, so I wouldnât have much of a concern. Also, having a bit of a snug fit will assist with keeping things in place (although latex doesnât tend to travel too much due to its higher coefficient of friction).
Phoenix
Hi Phoenix,
That is very helpful information. I ended up purchasing a 9 inch stretch cotton-polyester blend cover, which appears to be of good quality. I wanted to feel as much of the latex as I could so decided not to go too stiff on the cover. This size leaves me the option to put my 20 ild, 28 ild layer and 35 poly layer inside, but also to switch out the poly layer on the bottom for 3 inches latex for a full latex build. I might do this someday, depending on how long the poly lasts or if I get adventurous. Right now I am waiting on my 28 ild middle layer in the mail, which will be here in two days. I did buy a mattress protector with a polyurethane film as well.
While I wait to assemble my bed I was wondering ( for future reference) if you could enlighten me as to the safest way to soften OR firm up a mattress of latex made in the 3 layer config. I know I am getting ahead of myself here but in case the situation arises, what is the difference from adjusting from the bottom up vs. the top down? This is assuming I only have a 9 inch mattress cover to work with, which is true. Letâs say I had s-m-f, and wanted to soften the bed but not risk alignment. Would the safest bet be switching out the firm bottom for a medium? On top I obviously canât go softer than soft, and switching the medium out for a soft Iâve already experienced to be too soft( with two softs). Iâve been told by another source that changes made to the bottom are like half changes in feel, not sure how accurate that is. Or conversely if I wanted to go firmer it would be easier since I would already own a medium and could put the soft in the middle layer I suppose. I canât foresee having to do these changes at this point but it might be nice to know I knew what options I had if I did have to. I suppose the biggest advantage of the 3 layer system is these adjustments, and having one soft-medium and firm may offer at least 2 or 3 adjustments. Although you probably would not want to put a soft on the bottom I read on this forum, since it would be a waste of a soft. Thanks for any information, I canât seem to find an exact answer in my search thus far.
Hi gardenguy,
In general, changes made to the uppermost layers of a mattress will have a more dramatic effect on the perception of softness versus changes made in the deeper layers. In the hypothetical you described, changing the transition layer to a lower 20s ILD in Talalay or Dunlop would create a bit of a softer feel. Changing to a softer support core would also result in the mattress feeling a bit softer, but there would be a larger potential for a negative impact upon alignment.
Phoenix
this has been my experience with memory foam as well. anything less than the ultra high densities such as those used in the tempurpedic etc seem to provide barely any support at all for someone of my BMI (185lbs, 6â1"). I melt right through my Addableâs 2" 4lb gel memfoam layer making it mostly worthless at best and a hammocking risk at worst.
maybe memfoam is good when you put something between it and your body to prevent it from getting warm and melting too much, but idk most memory foam mattress layers seem like just a gimmick to me.
Hi Ajohnson,
All memory foam is generally quite plush (usually low to mid-teens in ILD), and a higher density isnât necessarily a âfirmerâ memory foam (there really isnât a memory foam used in mattress construction that would be considered âfirmâ). When memory foam mattresses are described as âfirmâ, this is mostly a function of the combination of materials beneath the memory foam. Memory foam can be manufactured with different speeds of response and sensitivity to temperature, and there are brands whose 5 lb memory foam actually has a âfirmerâ feel than their 7 lb memory foam. But expecting a memory foam layer to be supportive would be incorrect, as that is not what the product is designed to do.
While I understand your opinion, most memory foam mattress layers certainly arenât âa gimmickâ, but a legitimate comfort layer used within a mattress whose durability is mostly density-dependent, and like any other comfort layer the overall comfort provided depends upon the thickness, ILD, ordering and combination with other materials within a finished mattress, and the preference for such, like any other comfort material, is subjective and personal.
Phoenix
Hi Phoenix,
I have run into a hiccup on my DIY hybrid latex mattress build. I was wondering if I could get a few suggestions. The 19-22 layer over the 28-32 layer is causing a lot of pressure in my shoulders, to the point where I canât stay asleep at night. Itâs quite painful really. I think at my weight and pressure point issues itâs just too firm. So my set-up once again is 4 inch 35 ild poly foam, 3 inch 28-32 ild natural talalay latex, 3 inch 19-22 ild latex. Iâm not sure if I should return the 28 layer and change it out for a 23-27 in 2 or 3 inch. Or maybe add another 2 inches of 19-22 on top and keep the 28. Iâve been struggling to make latex work for me for around 3 weeks now. Iâm not sure how much longer I can hang in there, as itâs causing some pretty moderate sleep disturbances at this point. I sometimes wonder if I should have just done two 19-22 ild softs over my poly foam but I didnât want to risk alignment.