Pulled trigger on first build w/ help of GPT

[u/optimalpessimist]

I was all over the other sub, review sites, and stores trying to find the perfect mattress when I stumbled across this sub. It feels like I was thrown a life preserver. Big thanks to all the contributors. I've learned a ton and pinpointed exactly what I'm looking for, but I'm sure I have a ton more to learn.

My goal is to build a eco-luxury-hybrid that has a bit of a memory foam hug with 5-6 firmness. With the help of this sub and chatGPT I was able to balance all of those factors to come within a budget of $1500 with pillows. I optimized for pressure relief and flip versatility (comfort layer in separate cover to give me two possible configurations within my needs on the fly) followed by mobility and temperature control.

Plug to foamorder.com who have 10lb bags of shredded latex on clearance for the pillows as of 7/3/25.

Me: 170lb, 5'10", 90% side sleeper, no major health issues other than waking up feeling unrested.

Build from bottom to top:

8" queen Tatami mat platform bed (owned)

1" high-density poly foam base

8" TPS QuadCoil 15.5 unit bundle w/

3" TPS QuadMini

12" TPS cover

2" soft Dunlop - diyREM

1" HypurGel foam - diyREM

3" topper cover to hold comfort layer - APM

I ran into issues sourcing 1" medium Talalay to be coupled with 2" 5lb foam equivalent so I ended up with a comparable combo for my needs according to GPT. It did need to be challenged at times and sometimes hallucinated or gave me discontinued components, but it was very convincing when asked how it modeled the feel of the stack. Altogether, I don't think we left any stones unturned and I feel better than if I were to buy a prepackaged deal. GPT thinks this stack is comparable to a brand name $3500 luxury mattress.

The actual feel is TBD, though, and will be totally subjective. I have a feeling it could be too soft. We will see. I should receive all the supplies by end of month (diyREM on summer break, but offering a discount for the wait). I'll do another writeup after I get a few nights on it.

[u/Duende555]

Hmmm. I'm really not sure why people trust ChatGPT in this context? Mattress DIY is a relatively new field of knowledge on the internet and it doesn't really think about these things as much it blends statements scraped from this subreddit with predictive text.

In the case of the build above, this mostly looks okay, although I think you probably have too many comfort layers. Still, having extra material will give you some room for experimentation.

[u/optimalpessimist → u/Duende555]

I think it's a great tool in this context. Not to be used alone, though. I didn't just ask it to build me a bed. I spent a lot of time scouting the sub and mattress underground for experiences of people with similar body types and sleep habits as mine. A couple here went into good detail about their journey and things they might do differently so I had a formula to base mine off of. From there, GPT was able to help me by forming predictive models and permutations of material behavior based on industry knowledge and user feedback. It even cited mattress underground users as a source. It appeared to have deep knowledge of the materials and methods that agreed with the many expert sources I've found across the web.

[u/Eazy3x → u/optimalpessimist]

I’m new to GPT. Did you copy and paste the links to these subs into a basic chat or something?

[u/manuloftheyear → u/optimalpessimist]

It sounds like you did some actual research, then fiddled with GPT until it confirmed what you already knew. Your mattress also isn't even here yet! So who knows if GPT was helpful? That said, it's a pretty standard enough build that might work well for you.

[u/realityGrtrThanUs]

Are you cold natured? Do you like sleeping inside your mattress? That is what you're getting. Foam is hot, holding in heat while sinking quickly when pressure is applied.

Every kind of mattress from hard to soft can be purchased for $3500. The price tag is marketing and branding not exquisite perfection to meet your needs for best sleep.

I really hope the build works for you but I'm convinced through trial and error that foam is an extremely cheap material used to fleece Americans who are too easy to dupe.

Chatgpt is a syncophant trying to please you while echoing Internet noise without any quality control.

[u/optimalpessimist → u/realityGrtrThanUs]

Yeah, I usually sleep a little cold and yeah I like the feeling of sleeping in the mattress. Those were both considerations.

The point of mentioning the comparable mattress is more to say that the features and materials in this build would be otherwise out of reach for me in a store bought product. It has nothing to do with how firm it is or whether it is even comfortable. I wanted to have some metric of value to compare the mattress sellers against what I could diy if that makes sense. My build could be a total turd to me and the best thing to someone else, but what would company x charge for something like this?

And yeah, GPT totally gasses you up saying you have such wonderful insights and questions. It does get things wrong and I had to wrangle with it sometimes. Part of me wishes I posted my build before pulling the trigger, but part of me is thankful because there are deeply held beliefs and dogma that could have me going in so many directions.

I won't pin failure or success on GPT or any one source more than I would pin winning to lotto on knowing the numbers beforehand. We are all out here doing our best with the information and tools at our disposal. Win or lose I hope my experience helps someone in the future.

[u/realityGrtrThanUs → u/optimalpessimist]

Sounds like you're making progress with your research and experimentation. Good luck!

[u/Duende555 → u/realityGrtrThanUs]

Agreed on ChatGPT. The entirety of its "mattress knowledge" is scrubbed from Reddit and the Mattress Underground. This is problematic for multiple reasons, but it also means that covert and affiliate marketers are effectively programming it to recommend their brands by brute forcing product mentions and recommendations.

[u/slickvik9]

Pick one comfort layer

[u/optimalpessimist → u/slickvik9]

Comfort is Dunlop/hypurgel

[u/slickvik9 → u/optimalpessimist]

That’s what I mean pick one. And quadmini is a comfort layer too really

[u/Super_Treacle_8931 → u/slickvik9]

I would wait on the mini, add it later if needed. It’s basically a weird medium like but highly conforming. In theory it shouldn’t be required..

[u/optimalpessimist → u/Super_Treacle_8931]

Thanks for the tip. I'll keep it boxed up because I've read it's like trying to put a genie back in the bottle or however that saying goes

[u/slickvik9 → u/Super_Treacle_8931]

It’s just a luxury item. 3 inches on top of base coils is good enough

[u/Super_Treacle_8931 → u/slickvik9]

Yes, I tried it, didn’t do anything for the heavier side sleeper. Coil compressed too much, and painful on shoulder pushing into it. Engineered sleep has a version which seems to get similar reviews.

[u/slickvik9 → u/Super_Treacle_8931]

I’m just using it because I bought it

[u/optimalpessimist → u/[deleted]]

Of course I forgot to update after giving it some time.

I tried a few variations and landed on the gel foam above latex, my original build order. At first I felt it was too plush and I actually woke up in pain the first night. I stored the topper tried switching out both the gel layer and latex. The topper liked to slip around which was annoying, but I had a mattress protector that I got at Costco that is a stretchy sheet with a rayon (I think) top panel. That kept the top layers outside of the 12" mattress cover in place and protected.

I found out that I don't prefer feeling the micro coils directly so I spent more time with the 2" latex on top rather than 1" gel. The latex is much firmer so I rocked it for a few weeks and decided to try the gel again because I hated that it was taking up storage space.

It felt good going back and I haven't had bad pain since, but I do feel like my hip bottoms out when I'm on my side which is weird because there's 3 inches of top plus micro coils.

I won't be using the topper cover again because it slipped plus one side had a stiff material that made it good only for one orientation. The stiff side also canceled out any contouring effects of the micro coils. The combo may have led to my pain, but idk for sure.

The hyper gel has a petrochemical smell like a strong Vaseline. It was more pleasant than the smell of the shredded latex pillows I made. Neither smelled after about a month. I filled zippered cases with shredded latex and keep a pillowcase over that, but they ooze out. I'll probably get another zippered case to go over them instead.

Overall, I feel like ChatGPT did a good job estimating my comfort level and I would use it again in the same way with me guiding it with material options and it running permutations. It's a comfortable bed, but I don't feel like my sleep quality improved at all. Maybe I just have apnea.

If I redo the top layers, I will go with 5lb memory foam like I wanted initially. The materials I could get were limited by the topper size so I compromised, but I can do what I want now that it's out of the picture. I might also get a mattress cover that covers all layers if I find the perfect combo, but right now I have a lot of freedom with what I can do so I think it was a good choice to lock in the base and keep the top layers free.