Help with an "adjustment" to a DIY latex build

Hello all,

First, I apologize in advance for the lengthy post. If Phoenix recognized my username and remembers my OCD tendencies, I’m sure he groaned loudly and rolled his eyes with a “here we go again” expression, lol.

This forum, and Phoenix in particular, was a great resource last year during my search for a new queen bed, and my eventual attempt at replicating a latex mattress that I found in a local chain. The saga (and it was definitely a saga!) is primarily outlined in the threads I started here and here.

After several months of “research”, I purchased a 3" layer of Radium’s 22 ILD blended talalay from Arizona Mattress Co. I also purchased a 3" layer of 4.75 lb/ft3 and a 3" layer 5.9 lb/ft3 of Latex Green’s natural dunlop from Ultimate Sleep’s Amazon store. FWIW, I originally purchased the dunlop layers from SleepWarehouse.com, but what I received was no where near the densities of what I ordered. Although determining density is fairly straightforward, it took a bit of work to get SleepWarehouse to concede the layers were not within spec. They were eventually returned at their cost and a refund was provided. I then made the purchase from Ultimate Sleep and received the two layers that are within spec, at least in regards to density. To add to the delays, Arizona Mattress Co. originally sent me a 19 ILD layer instead of the 22 ILD I ordered. Arizona Mattress Co. made it right and did the exchange at their cost without much ado, which is why I decided to continue business with them and also purchased their 9" mattress cover and queen foundation. When all was said and done, I didn’t get the mattress put together until about last August.

From top to bottom, this is the layering, which I think would be considered a “differential” layering:

3" blended talalay in 22 ILD
3" dunlop in 4.62 lb/ft3, which is about 23-27 ILD
3" dunlop in 6.0 lb/ft3, which is in the high 40’s ILD

(The ILDs on the dunlop come from information provided by Phoenix in this post here.)

I am about 5’11" and 185 lbs, and I guess I would be considered a side sleeper. The reason I say “I guess” is because, unlike all the pictures used to demonstrate a side sleeper, my legs are not stacked on top of one another. I sleep on my side with my top leg forward and the knee pulled up, usually with my arm around another pillow. This results in somewhat of a side/stomach position.

From the beginning, I felt my DIY mattress was a bit too firm and have found myself tossing and turning due to pressure on my shoulders and hips. I do sometimes sleep on my back, and I don’t feel any undue pressure in that position. I I just don’t prefer being on my back and normally can’t fall asleep in that position.

Because of the pressure that builds up on my shoulders (the worst part) and hips (not as bad as shoulders, but definitely not comfortable), I end up flipping back and forth from my right and left sides all night long. Since I don’t have any issues with back pain throughout the night or in the morning, I’m thinking I need to make the adjustment in the top comfort layer, and that is what I have been researching these past couple days.

A couple of things have me concerned with simply trying to swap the 22 ILD top layer for a 14 ILD (Latex International’s blended talalay) or 15 ILD (Radium’s blended talalay in that same range). Radium and LI both make a 19 ILD, but my initial thoughts were that would not be a big enough difference from the 22 ILD. That was until I went back and reviewed the weight of my 22 ILD layer (28.5 lbs), which puts the density at 3.42 lb/ft3. According to that same post above, this possibly puts the actual ILD of my nominal “22 ILD” at closer to 24 ILD. I don’t think that is an unreasonable conclusion since LI and Radium both give a variance of +/- 2 ILD of the target ILD.

So if my nominal “22 ILD” layer is actually closer to a 24 ILD, and a nominal “19 ILD” could actually be as soft as 17 ILD (because of the +/- 2 variance), then what is the likelihood that going from a 24 to a 17 would be a big enough difference? On the other hand, but by the same reasoning, I’m concerned that swapping for the nominal “14” or “15” ILD might be too soft, especially if what I actually received was a piece on the lower ended of the variance, which means it could actually be 12 or 13 ILD.

I like the feel of a very soft and plush bed, so when I say I am concerned that swapping for a nominal 14 or 15 ILD layer might be “too soft”, what I am really concerned with is whether or not it would not be supportive enough. I know that support is primarily a function of the middle and bottom layers, but with the top layer being 3" thick, is it not responsible for any of the support? Meaning, if the middle and bottom layers are supportive enough, does it matter at all (in regards to proper support) how soft the top layer is?

In the interest of complete information, my wife, who is 5’8" and about 135 lbs, and is a side sleeper, says she has no complaints. She did have a sore neck for the first couple months on the new mattress, but after I was finally able to convince her to try a new pillow, the pain went away and she has had no problems. She also likes soft and plush mattresses, so as long as what I end up with still provides proper support, I think she’ll be fine with it.

For clarity, my questions are:

[ol]
[li]Based on the information I’ve provided, do you think I am correct in my assumption that the top lay is what I need to adjust?[/li]
[li]If the answer to #1 is “yes”, would a nominal 14/15 or 19 ILD have a better chance of fixing my problem, or is it a crap shoot?[/li]
[li]Should I be concerned that a softer 3" top layer will effect the support properties of the mattress, or should I just be concerned with the comfort aspects when making a decision on which top layer to use?[/li]

[/ol]As always, thanks for your time and input.

  • Eric

Hi ehuesman,

You are inside the range of fine tuning and smaller or more subtle changes where it’s really impossible to use specs (either yours or the materials) to predict how the changes you are considering will affect you with any certainty because the unknowns and variables including differences in body types and weight distribution along with sleeping positions, physiology, and individual sensitivities can be an even bigger factor than the changes themselves. When you are in this position then your own “educated best judgement” based on your own personal experience would probably be more accurate than anything someone else could suggest to you.

There isn’t a specific definition of progressive or differential layering and these are just concepts or terms I use to clarify different types of approaches to mattress design. While it doesn’t really matter which one it is … yours would be more of a “progressive” approach where you have the firmest layer on the bottom and the layers become progressively softer as you move to the top. A design that I would call more “differential” would be a two layer mattress with something like a 6" firm core with a much softer 3" comfort layer on top of it with no transition layer in between them so there would be a much bigger differential in the ILD’s of the two layers.

Support is really a very vague term and it really depends on what part of the body you are talking about “supporting”. A hard floor for example would have poor support overall because it wouldn’t support the inward curves of the human body and would only “support” the contact points (hips and shoulders) so the rest of the body would “sag” down to the floor because there was nothing underneath them to help hold them up. I would keep in mind that a mattress that is suitable in terms of alignment needs to “stop” some parts of the body from sinking down too far (such as the hips) and “allow” other parts to sink in more (such as the shoulders) and also “fill in” all the gaps in the body profile. There is more about primary and secondary support and their relationship to pressure relief in post #4 here. There is also more information in post #2 here that talks about the various “symptoms” that people may experience on a mattress and some of the possible causes for them that can help with the “detective work” and trial and error that may be necessary to reach your ideal combination of layers.

Deep support (or what I call “primary support”) that stops the heavier parts of the body from sinking down too far comes primarily from the deeper layers. What I call secondary support is the support that fills in the recessed gaps of the body and is primarily the function of the upper layers (along with pressure relief). Middle or transition layers will help with and affect both. The need for some parts of the body to sink in more easily into softer layers for pressure relief and secondary support and for other parts to be “stopped” from sinking too far by firmer layers for better alignment are conflicting and the challenge is always to find the best balance between them. Comfort layers that are too thick/soft can be risky for alignment so the “safest” approach is usually “just enough” in terms of thickness and softness to relieve pressure in your most pressure prone sleeping positions so that you have the least possible risk of alignment issues. “Just enough” can vary widely between people.

There are too many variables and unknowns and I don’t have enough reference points of combinations you have slept on for me to know but the difference in ILD would be relatively small and I’m not sure I would have any confidence in a weight based calculation that tried to determine ILD with the specificity you are looking for. Most people wouldn’t feel a difference of 2 or 3 ILD anyway and ILD also isn’t consistent across the surface of the layer (it varies from spot to spot by several ILD).

Having said that … if your layer really was 24 ILD and you changed to a layer that was 17 ILD which is a 7 ILD difference (and again it wouldn’t be possible to be that specific) then most people would likely notice a difference but there would be no way to know if it was “enough” difference until you slept on it.

If I was in your shoes and since you can’t return your current layer anyway I would probably consider adding a topper where you can work with both the the thickness and the ILD of your upper softer layers rather than only working within the limitations of changing a 3" layer.“act” firmer than if the same layer was Talalay and softening up this layer would also make a difference in pressure relief.

I don’t know but “just enough” thickness and softness would probably have the least possible risk for alignment issues so I would tend to avoid the softest ILD’s in thicker layers at your weight unless it was clear that there was no other alternative.

Again the goal is alignment (and the different levels of support under different parts of your body is just a means to an end) but every change to pressure relief will also have a corresponding effect on support (you need to sink in more to improve pressure relief and sink in less to improve support) so the key is finding the balance between them where both are inside the range that is suitable for you and the mattress also has the “feel” that you prefer (and feel is different again from either pressure relief and support).

If you do decide to go in the direction of adding a topper then post #2 here and the topper guidelines it links to has more information that can help you use your sleeping experience as a reference point for choosing the thickness and softness of a topper that has the best chance of working well for you.

Phoenix