Has anyone made a DIY foam mattress?

[RedmondStash]

Has anyone made a comfortable DIY foam mattress? I keep trying big-brand ones, and for the past decade or so, they haven't had enough lumbar support. Plus, after a year or two, there's sag at the hip that aggravates my existing low-back problems. And I also really need pressure-point relief and a little cushiness to sleep well. So I need a really firm base, especially in the lumbar area, with a really soft top.

The most comfy I've been was when I flipped over my Leesa bed-in-a-box mattress after it got too soft, and put a 2-inch memory foam topper directly on the (upside-down) base layer. For a couple of months, it was great -- but then the indentations got too deep for my low back, and I had to start over.

I'm thinking -- maybe a 4-inch or 6-inch block of high-density foam, plus a couple of toppers I already own, because I've been trying to modify mattresses for years now.

I've read through this:

https://forum.mrmoneymustache.com/do-it-yourself-forum!/is-there-an-alternative-to-a-commercially-made-mattress/

and looked at this:

https://openyoureyesbedding.com/

but haven't really found the answers I'd hoped for.

Thoughts?

[uniwelder]

You might want to look at this ongoing thread in the forums, as some of the comments are similar to what you're asking----https://forum.mrmoneymustache.com/ask-a-mustachian/how-do-i-get-a-good-bed/

[BudgetSlasher]

I do not have a specific thread to point you to, but if you are doing research you might want to wonder to some RV forums. Many people there are creating their own mattresses, especially those that are DIY converting a van/box truck/bus into an RV and have a non-standard sized sleeping area.

[HipGnosis]

I did.  And it's lasted 18 yrs - but has developed a soft spot - I like that I can move around (I live alone) to have soft - firm, but the soft spot is growing.

I bought a 5" firm latex queen mattress.  The link to where I got it now goes to somewhere that sells garden and lawn placards...

I bought a full size 3", 4 lb, memory foam topper.  I laid it across the foam mattress sideways and cut the extra off with a serrated bread knife.
I got 3", 30 Indentation Load Deflection (ILD) (30 lb to deflect (compress) 25%) Reflex Foam.
I put the memory foam on the mattress to be from my shoulders to my hips.   I cut and placed the reflex foam to cover the rest of the mattress,
I got a mattress cover that holds it all together.

I replaced the memory foam a few yrs ago. 
Next time, I'll get a queen 2" memory foam topper and toss the reflex foam.  I'm thinking it'll be bamboo charcoal infused.  But I'll see what's available when the time comes.
For your 'pressure point' issues, I think you'd want thicker memory foam.

[RedmondStash]

Good tips here. Thanks, everyone.

[moneypitfeeder]

I made one using 3 latex foam toppers--with holes drilled or cast in them for breathability--in different degrees of firmness. Then I ordered a cover from: https://www.foambymail.com/GWCC-/custom-gray-and-white-striped-cover.html. Made it easy to swap the layers to customize the firmness.