Hi danuhoh,
The quilting layer in a mattress is part of the cover and can serve many functions but in the case of polyfoam one of these is to provide a softer hand feel and lower resilience to the mattress. These are generally softer foams and as long as they are thin enough they will modify the performance and feel of the layers below it (which is one of the reasons they are there) but won’t be thick enough to have a major effect on the durability of the mattress as a whole when they soften. If a quilting layer softens … it will generally allow the layers below it to “come through” more and because they are already soft by design … as long as they are thin enough then further softening won’t affect alignment.
The “guideline” I normally suggest is around an inch or so. Once you get into the range of 2" or more (either in a quilting layer or in the comfort layers … then if the material softens (or in the case of fibers compresses) then it can have a larger effect on the feel and performance of the mattress and in the case of foam softening can begin to affect alignment as well because they can allow the heavier parts of the body to sink in too far before they reach the firmer support layers. In other words they can cause the sinking in to be uneven.
So in the case of the Ultimate Dreams … they are in the “inch or so” guideline where foam softening wouldn’t present a real issue. They can also vary the quilt patten to make it either firmer or softer for an “in between” softness rating. In some cases … if the latex layer underneath it was on the firmer side … then the softening of the quilting layer could even increase the perceived firmness of the mattress slightly as the firmness of the latex would “come through” more. The type of foam they use is a special quilting foam that is resistant to tearing and is usually a “high performance” polyfoam.
You could use other mattresses that you have tested as a guideline but bear in mind that every layer of a mattress and the types of materials used will affect the overall performance and feel. The specs on the Englander for example are very incomplete in terms of thickness and ILD of all the layers and it would also have a different (possibly thicker) quilting layer. They also use Dunlop latex which is also a good quality material (especially if it is 100% natural) but will feel and perform differently from Talalay latex. It also doesn’t list the firmness of the support layers and in addition to this … I would question the ILD ratings of Dunlop when they are listed in the range of high teens or low 20’s. While it’s possible that this is accurate … it is also possible that it is listed as having a softer ILD range than it really is (a lot of the Dunlop has ILD specs that I don’t believe are accurate and the knowledge of the retailer is often important for finding out what it really is).
All mattresses need to have a combination of firmer layers and softer layers so a single rating (such as “medium firm”) is never accurate and often misleading because it is more about the overall “feel” of the mattress (each person may “rate” this differently and the same description will vary from manufacturer to manufacturer and store to store) and not about the specific softness/firmness of the comfort and support layers. Support has two components and each would need to be a different softness/thickness so a separate “rating” for each would be much more accurate. For example “soft over firm” or “medium over ultra firm”.
The deeper layers of a mattress provide the primary support which “stops” the heavier parts of the body (hips/pelvis) from sinking in too far which can leads to a pelvic tilt that puts the spine out of alignment. Secondary support comes from the comfort layers which has a dual purpose of providing pressure relief and also filling in the gaps in the sleeping profile and helping to maintain the natural alignment of the spinal curves. If this layer is too thick and soft, it can allow the heavier hips/pelvis to “travel” too far before it reaches the support layers and again lead to misalignment.
These layers interact so the support layers or “deeper zone” of the mattress will “help” the comfort layers to different degrees and the upper comfort layers or comfort “zone” (or the transition layers in between) can modify the primary support of the mattress as well.
So the goal is to have a comfort layer that is thick and soft enough to relieve pressure and fill in the gaps for secondary support along with a support layer that is firm enough to stop the hips/pelvis from sinking in too far. The firmness of the comfort layer or zone will generally have more to do with pressure relief than with what people typically call “support”. If the lighter wider parts (such as the shoulders) are not “allowed” to sink in far enough or the heavier parts are not “stopped” quickly enough … you will sink into the mattress unevenly and the end result of a mattress that is either too firm, soft, or thick in some of the layers will be misalignment (poor support). You can see a diagram of this here.
For your back issue (or any back issue) the “ideal” is to use a combination of layer thickness and layer softness that allows your unique body type to sink in evenly and maintain its natural alignment in all your sleeping positions. This involves a combination of materials that “allow” some parts to sink in enough (primarily upper body and shoulders), “stop” some parts from sinking in too much (primarily lower body hips/pelvis), and “filling in” the gaps with enough resilient material that the natural curves of the spine are maintained and supported with “just the right amount” of firmness (such as the lumbar curve of the lower back). In addition to this … the overall depth you sink in can either increase of decrease the amount of pressure/support under the lumbar curves and if someone is used to a softer level of secondary support then a lower resilience and less “support” under these areas can be more comfortable for some (which is why a polyfoam quilting layer is often used over latex).
All of this is part of the “art and science” of mattress theory and construction and the most accurate way to know this for any specific person is either through personal testing with the help and guidance of someone who has the knowledge and experience to help you make the most appropriate choices or online with a manufacturer who knows how all the layers of their mattress interact with each other and with different people, body types, and sleeping positions and has a customer base that can be used as a reference point to help “match” different people to others that are in the same general range of needs and preferences. In the case of Dreamfoam and the other online providers of this site … they are very good at this.
Their “default” firmess level for the 3" latex layer is 28 ILD which is firmer than what would be typical for a latex comfort layer that had no quilting but also takes into account that erring on the side of firmness is always a good idea (a mattress comfort layer can always be softened with a mattress pad or topper) and also that the quilting would make the 3" latex comfort layer thicker/softer than sleeping directly on the latex so a “latex equivalent” if you were directly on the latex would be a softer ILD.
In a comfort layer that was thinner … then a softer ILD may be appropriate depending on the softness/firmness of the support layers while with a thicker comfort layer … then a little firmer may be better (again depending on the body type and the firmness of the support layers).
The bottom line of all of this more complex explanation is really to re-inforce the importance of working with a manufacturer for more specific recommendations that can be more accurate than what I call “theory at a distance” which doesn’t take every layer and component into account and doesn’t have a reference point of a specific mattress (where all the details are known) or customer base that can be used to “match” each person’s needs and preferences as closely as possible.
You may have seen this already but some possible latex and latex hybrid options in the Albany area are in post #4 here which may provide a more accurate reference point than the Englander…
Phoenix