Hi Waterdragon,
I’m guessing you are referring to what are called “component” mattresses with individual components that fit inside a zip cover where you can choose each individual layer or component separately and where the components or layers can be re-arranged or exchanged after a purchase if you need to make any changes to the comfort or support of your mattress. If this is what you mean then the mattress shopping tutorial here includes a link (in the optional online step) to a list of the members here that sell mattresses online and many of these have a wide range of different types of component kit mattresses.
If you are intrigued by designing your own mattress and buying the individual components separately rather than as a kit that already includes all the components then I would read option #3 in post #15 here first so you have more realistic expectations of success and the learning curve and trial and error (or extra costs of replacing layers if you make any “mistakes”) that can be involved. If you do decide that this is a challenge that you would like to take on then the component post here includes a list of some of the better component suppliers that I’m aware of.
[quote]I can’t afford all organic. Latex and/or foam made from petrochemicals are out of the question. But a support layer made from natural (well washed) materials plus a separate comfort layer made from organic materials might work. Even everything made from natural (well washed) materials would be better than having any latex and/or materials made from petrochemicals.
Have you got any ideas about this?[/quote]
There is more about organic, natural, safe, “chemical free”, and green materials in post #2 here and the posts it links to that may help you decide on which materials you are comfortable having inside your mattress. 100% natural or organic rubber comes from a rubber tree and doesn’t include any synthetic rubber made from petrochemicals (although there are a small amount of chemicals used to foam, manufacture, cure, and protect the latex) but any latex you will come across (either Dunlop or Talalay made with either natural rubber, synthetic rubber, or a blend of both) will have been tested for harmful substances and VOC’s either by Oeko-Tex or Eco-Institut for harmful substances and VOC’s to the same standards that are used for natural latex and by most people’s standards or sensitivities would be safe.
Phoenix