Hi B Feelgood,
All the layers and components in a mattress will affect the “feel” and performance of all the other layers both above and below it so what you feel on a mattress is a combination of the “feel” and firmness and properties of all the layers … not just specific layers so any mattress that uses a different combination of materials and components will be different from another mattress.
All the layers of a mattress compress simultaneously (one doesn’t start compressing when the ones above it are “finished” compressing) but they each compress to a different degree or percentage of their thickness based on their firmness level, thickness, what is above them, and how deep they are inside the mattress. Softer layers compress more than firmer layers, thicker layers compress more than thinner layers, all layers compress less when there are thicker or firmer layers above them, and upper layers compress more than deeper layers.
If you were to change the middle layer of your mattress and replace it with a different layer (either a different thickness, a different firmness, or a different type of material) you would almost certainly feel a difference and if you were to take the top two layers of your mattress and put them on the floor (and remove the bottom layer completely) you would also feel a significant difference.
There is more about a few of the different properties or specs of different materials that can affect the feel and performance of a mattress in post #2 here and in post #4 here.
There is also more about primary or “deep” support and secondary or “surface” support and their relationship to firmness and pressure relief and the “roles” of different layers in a mattress in post #2 here and in post #4 here that may also be helpful in clarifying the difference between “support” and “pressure relief” and “feel”.
While your body may not physically “touch” the bottom layer … the bottom layer will still compress to some degree (how much will depend on the body type and sleeping position of the person and on the specifics of the layers above the support core) and any layer in a mattress that compresses under your weight will affect the feel and performance of a mattress.
There is more about some of the differences between an all latex mattress and a latex/polyfoam hybrid in post #2 here.
Even something that is seemingly as simple as firmness can be misleading because there are no “standard” definitions or consensus of opinions for firmness ratings and different manufacturers can rate their mattresses very differently than others so a mattress that one manufacturer rates as being a specific firmness could be rated very differently by another manufacturer.
Different people can also have very different perceptions of firmness and softness compared to others as well and a mattress that feels firm for one person can feel like “medium” for someone else or even “soft” for someone else (or vice versa) depending on their body type, sleeping style, physiology, their frame of reference based on what they are used to, and their individual sensitivity and perceptions. There are also different types of firmness and softness that different people may be sensitive to that can affect how they “rate” a mattress as well (see post #15 here) so different people can also have very different opinions on how two mattresses compare in terms of firmness and some people may rate one mattress as being firmer than another and someone else may rate them the other way around. This is all relative and very subjective and is as much an art as a science.
There is more about the different types and blends of latex in post #6 here but different types and blends of latex can certainly feel different from each other because they each have different properties. Outside of any differences in the layer thicknesses or layer firmnesses or the position of a layer in a mattress (what is above and below it) … natural latex will tend to be more resilient than synthetic latex and can also have a higher compression modulus than synthetic latex. Dunlop latex will also “feel” different from Talalay latex (see post #7 here).
The type or blend of latex is strictly a preference and a budget issue because any type or blend of latex comes in a wide range of firmness levels.
There is more about the different ways to choose the most suitable mattress (locally and online) that can help you assess and minimize the risks involved of making a choice that isn’t as suitable for you as you hoped for in post #2 here.
I would always keep in mind that the only reliable way to know for certain whether any mattress or combination of materials will be a good “match” for you in terms of “feel”, “comfort”, firmness, and PPP will be based on your own personal experience but when you can’t test a mattress in person then the most reliable source of guidance is always a more detailed phone conversation with a knowledgeable and experienced retailer or manufacturer that has your best interests at heart and who can help “talk you through” the specifics of their mattresses and the properties and “feel” of the materials they are using (fast or slow response, resilience, firmness etc) and the options they have available that may be the best “match” for you based on the information you provide them, any local testing you have done or mattresses you have slept on and liked or other mattresses you are considering that they are familiar with, and the “averages” of other customers that are similar to you. They will know more about “matching” their specific mattress designs and firmness levels to different body types, sleeping positions, and preferences (or to other mattresses that they are familiar with) than anyone else.
The thickness of any specific layer isn’t particularly meaningful by itself because it’s just one of many specs that will affect the feel and performance of a mattress in terms of PPP. You also wouldn’t be “bottoming out” onto any specific layer … it would just be the mattress “as a whole” that feels too firm for you.
Unless you have a great deal of knowledge and experience with different types of mattress materials and specs and different layering combinations and how they combine together and can translate them into your own “real life” experience that can be unique to you (which would only be a very small percentage of people) … I would tend to avoid using individual specs such as layer thicknesses or ILD numbers or other complex combinations of information or specifications to try and predict how a mattress will feel or perform for you and focus more on your own actual testing and/or personal experience. When you try and choose a mattress based on complex combinations of specs that you don’t fully understand then the most common outcome is information overload and “paralysis by analysis”.
While it’s not possible to make a blanket statement about sales because each retailer or manufacturer can be different … I would keep in mind that the better manufacturers and retailers don’t generally “negotiate” (see post #6 here) or have “fake sales” based on the time of year or holidays (see the guidelines here and post #5 here) and I would treat retailers or manufacturers that negotiate their prices or have “major holiday sales” with huge discounts as a red flag because manufacturers or retailers that sell good quality/value mattresses don’t need to negotiate or have “fake sales” to create a false sense of urgency and they generally sell good quality/value mattresses every day of the year at prices that are already very reasonable. Some online manufacturers do have ongoing rotating “sales” that change their name but the specifics of the sale tend to be similar.
Phoenix