Mattress modification
 

Please point out the flaws in my plan:
About 2.5 years ago, we bought a Tempurpedic mattress. Cloud Supreme breeze if it matters, all foam.
I've decided it's just too soft for me to sleep on, I sleep on my stomach and wake up with lower back pain, leading up to me pinching a nerve about 3 weeks ago and missing 3 days of work + a weekend. I'm still not 100%.
The plan - Tempurpedic sells replacement mattress covers, and a king is the same size as two twin xl mattresses. Can I remove the cover, cut the mattress in half and put it in two twin xl covers? I'd then try to stiffen one of them, with different foam or a slab of wood or something. Worst case I buy one twin xl mattress instead of two.
The wife thinks this is a terrible idea and thinks we should sell the existing mattress, but who wants a used mattress? Even if someone did, we wouldn't get near what we paid for it.
On the other hand she would also like adjustable bases, and to keep everyone happy we would have to have a split king.

tl;dr Can I cut a Tempur pedic mattress in half?

The only recommendation I have is, stop sleeping on your stomach. I slept that way as a young man until a gal I was sleeping with told me that’s the reason for my back issues. Took a while to break the habit but no more back problems.

If only it were that easy. If I sleep on my back I snore. If I sleep on my side I end up on my stomach by morning. I've been sleeping in the guest room on a 20 year old Therapedic Medicoil, old school two sided mattress, no issues and I sleep great.
We can't go a king firm mattress, my wife sleeps on her side and she gets pain in her hips if the mattress is too firm.

Please don't mention sleep number, tried it, hated it.

How about just opening the existing mattress cover, carefully along a side seam, and have a zipper installed. Then, you can open the cover and install whatever stiffener might work on your side only, try it out, and replace/substitute, until you find the ideal firmness.

I've played with mattresses a bunch. What you are doing is counter productive but there isn't much else you can do. Adding stiffness over softness doesn't make sense. Many foam mattresses whether memory or latex are built up using a combination of types and pound ratings. It's actually a complex equation to fit a mattress to the sleeper and few people can do it right. That doesn't mean you can't.

I had a Tempurpedic after making a foam assembly of my own. Mine was better and I was sorry I spent the money. I had stopped at a motel when I went up to San Jose to buy the Carrera I had and they featured Tempurpedic. I thought I was sold. It did wear out. You won't like this but I sleep on a Sleep Number. However, I have added 2 additional layers to the SN. This is exactly what they do in order to 'sell up' your purchase but they don't offer any particular combinations, just more stuff and at least one of those added layers is foam. In my case, and knowing through experimenting for 20 years, I actually made a SN into quite a nice bed.

Back to your Temp: first of all examine the construction and understand what is there. Ideally your new 'insert' would go somewhere in the middle but that would be next to impossible. If I was there with you, I might flip the entire mattress upside down and add something to the bottom which is now the top. If that worked, you could cut it in half and flip the one side back over right. Additionally, you possibly could get all of your mattress back into the original cover not needing any sewing. One might be higher than the other.

IIRC, there is a zipper around 270º of the mattress already.

This is an interesting thread and I'm subscribed. I'll add in going forth as I think this out more.

To answer your question, yes you can cut a foam mattress in half, and it's surprisingly easy. I cut up an old one with a serrated knife as a bed for my parents dog.

Just use very little pressure and it goes through like butter.

If we only lived closer, I'd swap you. My Tempurpedic is too firm and just ordered a new one online this morning......

Trying to sell our old one locally for $300. No sure how that will go???

which habit?

Go buy a cheap, firm mattress, and try it. We had sleep number, paid alot, hated it. Realized we slept better on vacation.

I also use this, or a full body pillow. Both make you to sleep on side: https://www.medcline.com/products/medcline-advanced-positioning-wedge/?utm_medium=cpc&gclid=EAIaIQobChMIj-uCt4mS4wIVAp-fCh2W7wRXEAQYBSABEgJ3XPD_BwE&gclsrc=aw.ds&sku=1356-07

The wife is dead set against "hacking up" (her words) the existing mattress, so I'm going to have to wait to check what's inside until Thursday. She has to work, so I'll have time. I did check out the review on Sleepopolis, he shows what is inside the Tempur Pedic.

The existing cover is zippered, and separates into top and bottom, you can either buy a replacement top, or the whole cover.

I guess I see two potential issues - I saw one photo where there's a sheet of some material over the top that is glued to the sides, and I wouldn't be able to re-glue it to the side where I cut it. The other issue would be if they did something with the newer mattresses to make the edge firmer, and only one edge would be firm. I have the 2.0 version of the mattress with the gray cover, not the original with the tan cover.

From the sleepopolis photos / video, it looks like all the layers are glued together, so it wouldn't be easy to separate the layers to add wood, so maybe that's out. I'm also wondering if what makes the firmer bed firmer is the foam is denser. But still, buying one twin xl is half the price of buying two, or I could just buy a conventional firm mattress for my side.

I did find a video of a guy cutting down a tempurpedic for a RV, he used an electric carving knife. He had to make two passes and they didn't line up perfect, but maybe once it's under the cover nobody would notice.

Oh boy. Repeat after me..... Happy Wife, Happy Life..... ;)

The sleeping on my tummy habit. The other habits have been refined.

Yes the layers are glued together to keep things lined up. The only way to separate the layers and have a precision cut with no bumps would be with a hot wire. I think inserting a piece of wood is a bad hack.

"Happy"
Order Summary
Subtotal $10,096.00
Your Savings July 4th -$1,000.00
$300 Instant Credit (XL) -$300.00
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Total $8,796.00

I'd like to explore other options before laying out another $9k after already spending about $4k on the first purchase. The $9k includes the adjustable bases. $6300 for two mattresses, 1 firm, 1 medium - medium soft.

I recommend a skill craft mattress...

My gf and I went bed shopping a few years ago as the new condo was finishing up. We got a Tempurpedic Contour Elite King, then upgraded to the Contour Elite Breeze after the 90 trial. At $5k for the mattress, I wouldn't think of hacking it up.

I see no harm in "hacking" into the current mattress. Looks like there is a back up plan if something goes wrong. If it works you don't need to get something new.

OK, I'm listening to the wife / chickening out on the plan.
I started to remove the cover this morning, and found out there's a second cover, so I can''t see the actual foam. It feels like the picture on Sleepopolis, multiple layers. It is also heavy AF, and I'm a little worried if I got the cover off I wouldn't get it back on again. So if you were hoping to see a guy cut a mattress in half, here you go -
https://www.youtube.com/watch?v=xAcYkOErOok

this is the video I originally watched.
https://www.youtube.com/watch?v=O2RjRm-LVdo

If you're snoring, get checked for Sleep Apnea, then get a cushion firm matt.

easier to soften up a hard matt than the other way around.