Hi johnsazzr,
I would keep in mind that your mattress will contain both memory foam in the upper layers and polyfoam in the deeper layers and you may need to check and make sure that any of the layers in your mattress that you plan to re-use are still in good condition. There is also some good information about “mattress surgery” in post #2 here and the posts it links to that may be helpful as well.
If you are planning to remove and replace all the foam layers in your mattress and only re-use the cover and you are attracted to the idea of designing and building your own DIY mattress out of separate components that are purchased from one or several different sources then the first place I would start is by reading option 3 in post #15 here and the posts it links to (and option #1 and #2 as well) so that you have more realistic expectations and that you are comfortable with the learning curve, uncertainty, trial and error, or in some cases the higher costs that may be involved in the DIY process. While it can certainly be a rewarding project … the best approach to a DIY mattress is a “spirit of adventure” where what you learn and the satisfaction that comes from the process itself is more important than any cost savings you may realize (which may or may not happen).
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” that may be useful as well.
For those who decide to take on the challenge then I would either use the specs (if they are available) of a mattress that you have tested and confirmed is a good match for you in terms of comfort, firmness, and PPP as a reference point or blueprint and try and “match” every layer and component in your reference mattress as closely as possible or alternatively use a “bottom up” approach (see post #2 here).
Some of the better online options I’m aware of that ship mattresses and/or foam layers and components (memory foam, polyfoam, and latex) across Canada are also listed in post #21 here and I also added a few additional options to the list today as well.
I don’t keep a record of the individual mattresses or components or their specs that the retailers and manufacturers in the hundreds of forum lists throughout the forum carry on their floor or have available online (it would be a bigger job than anyone could keep up with in a constantly changing market) but checking their websites and especially making some preliminary phone calls to the retailers/manufacturers that are on the lists that you are considering is always a good idea before you decide on which retailers or manufacturers you wish to deal with or visit anyway. This will tell you which of them carry mattresses or components that would meet your specific criteria, are fully transparent about the materials and components and/or the mattresses that they sell, and that carry the type of mattresses or components that you are interested in that are also in the budget range you are comfortable with. Once you have checked their websites and/or talked with the ones that interest you then you will be in a much better position to decide on the ones (if any) that you are most interested in considering or visiting based on the results of your preliminary research and conversations.
Phoenix