I’m hoping to build a split king for my wife and I. We currently sleep on a spring mattress (Phoenix combi-zone) with L&P Combi-Zone coils for support and their nanocoils for cushioning. Here’s their description:My wife (5’8", 180lb side sleeper with chronic back pain) likes this mattress but it gives me (6’ 210lb side sleeper) pretty severe shoulder and sometimes hip pain. I’m currently using a twin SOL 3" soft topper and that take the pain away, but I think I prefer memory foam. I haven’t slept on it for many nights but my mom had a Nectar Copper foam mattress that I took a picture of, I liked it so much. That’s 4" memory foam, 1" transition and a foam foundation.
My idea was to copy the foam example on the updated guide for my side:
6" 36 IUD foam from foam by mail
3" soft Energex - I could only find this as Titanflex at mattresstopper.com, customer service said it is Energex but their soft is 19 ILD energex; Duende555 calls for 18 ILD so I’m not positive about this.
I could also try my 3" soft latex topper here. Might be too soft but it could be worth a try.
2" Serene foam instead of the memory foam.
One thing that gives me pause on my build is we have a Novaform 14” Comfort Grande Advanced Gel Memory Foam, which they sell as a medium but it feels much too firm for me.
I’m not as sure on my wife’s side. I would like to use a foam base, but that makes it different than we have now. I thought about trying base foam with just the soft latex topper to get a baseline. She would also like the greener and natural selling points of latex. She likes the Novaform, so we can get a foam product to work.
Does anyone have any thoughts on this build? Or know more about the Titanflex?
It sounds like you’ve already done a great job thinking through both your comfort needs and your wife’s preferences. Building a split king is a smart way to make sure you each get the feel and support that work best for your individual bodies and sleep styles.
A few thoughts on your setup:
Your side: The layering you’re planning makes sense - firm, high-density base foam, topped with a responsive layer like Energex (or Titanflex, which is very similar), and then a softer, contouring comfort layer. The Energex/Titanflex “soft” (around 19 ILD) should still give you that buoyant, adaptive feel without letting your hips sink too far, especially at your weight. If you do end up preferring a more traditional memory foam feel, swapping the Serene foam for a higher-density (4 lb or more) memory foam layer could bring you closer to the Nectar comfort you liked.
Your wife’s side: Since she prefers the feel of the Novaform and also values natural materials, starting with a latex comfort layer over a supportive foam base makes sense. You can always tweak from there by adjusting the thickness or ILD of the latex topper or even introducing a thin transition layer (like 1" of softer foam) if she wants a touch more plushness without losing support.
Other considerations: Make sure both sides have consistent height and good edge alignment within the shared cover. It helps the bed feel cohesive even with different internal builds.
For sourcing, you might want to take a look at DIYMattress.com they carry high-quality foams, coils, and latex layers from reliable suppliers and make it easy to customize or replace components later if you need to fine-tune things.
You’re already doing exactly what we recommend: using your personal experience (what’s worked and what hasn’t) to inform a design that matches your specific needs. Once you’ve tested your first setup, come back and share how it feels - small adjustments can make a big difference, and we can help you dial it in even further.
I tried my setup and the softer two layers were too soft, my hips especially went through. So I tried the latex (soft Dunlap) over the base foam with Serene on top, that was better but I still need more of a transition. I did put the soft titanflex on top of our mattress and liked that a lot more than latex over the mattress, so we’re learning.
So I’ll order a medium titanflex/energex or some other foam, open to suggestions on that.
And my wife hasn’t didn’t much time on our trial setup so no feedback there.
If the soft Titanflex felt good, a medium Titanflex or Energex layer is a great next step since it should give you that responsive, buoyant feel you liked, while preventing the “bottoming out” you noticed with the softer layers.
Something in the 24–28 ILD (or around 30–35 firmness rating) range usually works well for side sleepers in your weight range when paired with a solid base.
You could also experiment with layer order once you have it . Sometimes putting the Titanflex over the Serene, or even trying a 1" transition layer between them, can fine-tune things nicely.
