Mattress Making

Shame

At some point in your life, it stops being acceptable to sleep on a twin mattress on the floor. If you are me, and you just turned 31, and your mom keeps asking you why you aren’t married yet, and WHAT DO YOU MEAN you don’t even have a girlfriend…and you find yourself looking at your twin mattress thinking that maybe a KING mattress will give your mom those grandkids she keeps asking for…then clearly the next step is get advice from a bunch of other 31 year old basement dwellers. You go to Reddit.

Because of course reddit has an entire community dedicated to mattresses. I spent days reading mattress reviews. Sleep number, tempur-pedic, purple, plank. My budget went from $500 to $1000 to $2000, until finally I realized that rent and food were unimportant, and I was checking the limit on my credit card and googling ‘how to get a loan for an $8000 mattress’…and then I found it, the dark underbelly of the reddit mattress community. The DIYers.

Revelation

That’s right. You can build your own mattress. If you kill enough geese and sew a few sheets around their discarded flight paraphernalia, then you too can have your very own mattress. But seriously, it turns out that even multi-thousand dollar mattresses are just a couple pieces of foam stacked on top of each other, with maybe a spring or two thrown in depending on the brand.

There are a couple of incredible guides written by famous redditor u/the_levathan711 on how to buy a mattress and how to build your own mattress, and if you are serious about buying or building your own mattress, then I highly recommend giving them a read.

Since these detailed sources of information already exist, this post will not be an exhaustive guide. However, I will attempt to at least outline the basics to give my own mattress build the needed context.

Mattress Design

Most mattresses are built with an overarching two-layer design principle: you have your comfort layer on top, which is soft and conforms to small variations in your body like the back of your head and your arms. Then there is the support layer, which is firmer and supports the heavier parts of your body like the hips.

Together, these layers should be soft enough to allow your body to settle into the mattress and align your spine, but they should be firm and thick enough that you don’t sink too far and hit the bedframe underneath. There are actually some other possible layers, like cooling layers on the top (which are usually scams) or transition layers that sit between the support and comfort layers, but from a design perspective, it’s good to think in terms of comfort and support.

Sleeping Position

The position you sleep in can greatly change the support or comfort layers you choose. The size of your body also matters, especially if you exist at the lighter or heavier ends of the spectrum, but at 5’9” and 175lbs I’m decidedly average and can follow most of the standard advice.

I stole this diagram from snoozzzmattress.com

If you look at this diagram, you can see that, depending on the sleeping position, parts of your body will need to sink into the mattress to keep your spine aligned. If you sleep on your side, then there will be a large protrusion at your hips and shoulders, so you will need a softer support layer that can give in these areas to allow spinal alignment. But if you are a stomach or back sleeper, you will need a firmer support layer, so your hips don’t sink too far and mis-align your spine.

I, myself, am a stomach sleeper, and have always preferred very firm beds. In fact for several years in high-school, I literally slept on the floor with some blankets. These days, that sort of behavior would give me shoulder pain, because although the floor provides a wonderfully firm support layer, it makes for an awful comfort layer, which should let my arms sink an inch or two into the mattress without creating pressure or cutting off circulation.

Materials and Measurements

ILD

However, ‘firm’ and ‘soft’ are somewhat vague concepts. Commercial foams use a metric called ILD, or Indentation Load Deflection, which reports how many pounds it takes for a 50 square inch circular indenter to compress foam to 25% of its original thickness. Athough this scale has it’s limitations, specifically when compression doesn’t have a linear relationship to force, it’s a great starting point for buying foam.

By this scale, 12 ILD would be quite soft and 50 ILD would be very firm.

lb/ft³

Density is another number which will often be thrown around, measured in lb/ft³. Although one would expect a denser foam to be a firmer foam, this is not always the case. Density instead serves as a metric for how high quality the foam is, as it directly relates to how long the foam will last before degrading.

For polyurethane, 1.5 lb/ft³ is low quality and 2.5 lb/ft³ is high quality. For memory foam, 3 lb/ft³ is considered low quality and 4-5 lb/ft³ is high quality.

Materials

If you want to go deep down the rabbit hole, it’s worth doing some dedicated reading on the differences between polyurethane, latex, and memory foam, but I’ll try to hit some of the highlights here.

Polyurethane

• inexpensive
• often used for support layers
• medium to long life, especially if a bottom layer

Latex

• expensive
• used for all layers
• longest life
• non-linear compression
• better spring-back for grandkid producing activities
• worse motion transfer

Memory Foam

• moderate price
• only comfort layer
• short life, as little as 3 years
• compresses further as it heats

Commercial Offerings

I didn’t look at too many commercial options, but just to give an idea of the value proposition for building your own bed, a firm option that I was considering was the Plank, by Brooklyn Bedding. Known for being one of the few genuinely firm beds on the market at a reasonable $1,500 for a king, I was curious how high quality the construction was.

I sent them a message and they were kind enough to give me a full breakdown of all the layers: essentially the entire bed is built with foam in between 1.5 and 1.8 lb/ft³. So for $1,500 you are getting a decidedly low quality mattress.

I don’t want to spoil it too much, but my final build was between 2.8 and 4.6 lb/ft³ depending on the layer, and cost only $763 for the configuration that I ended up keeping. Half price for double the quality.

My Mattress

For my design, I started with the guide from u/the_leviathan711 and went from there. My theory was that this build would have a firm base with a latex transistion layer and a thin 2in topper of soft memory foam. Hopefully this would give lots of support with a small buffer zone to remove pressure points.

I liked the idea of latex, but as a light sleeper I was worried about the motion transfer. So I was hoping I could get the best of both worlds by putting latex as a transition layer with a little memory foam on top.

Final Order

Product	Thk	ILD	lb/f3	Price	Kept?
4LB ViscoPLUSH Memory Foam Topper	2”	14	4.0	$154	yes
Dunlop Latex Foam Toppers	3”	29	4.6	$370	yes
HD36-HQ Foam - Standard Mattress	1”	35	2.8	$45	no
LUX-HQ Foam - Standard Mattress	4”	50	2.8	$183	yes

This was my initial order to foambymail. Having a perfectly fitting mattress cover is a big deal, and that 1” layer was meant to give me some dimensional flexibility if I wanted to add or remove any layers from the build (I ended up removing it.)

Data Sheets

You don’t need to read these, but if you are interested, here are the data sheets for each of the layers I bought

4lb ViscoPLUSH

Dunlop Latex

HD36-HQ

Lux-HQ

Testing

Comfort

My roommate also built a mattress, and we intentionally bought different layers, for example I got Dunlop 29 ILD latex, while he got Talay 34 latex. We spent a couple months rearranging and trying different options for sleeping before settling on our final configurations.

Motion Transfer

It’s worth noting that as a light sleeper, the complete absence of motion transfer was a primary design goal, and we did a LOT of tests with different layer configurations. We tried two different latexes on top, we tried both of them with memory foam on top. We tried putting the 1” HD36-HQ foam on top. And on and on.

Ultimately, latex really does transfer motion more. If you are sleeping directly on Dunlop 29 ILD latex, you will feel the other person get in and out of bed. However, adding the 2” memory foam layer on top almost eliminates this, without losing the compressive spring-back the latex provides underneath.

There exist some 20 ILD latexes that I may try in the future when my memory foam wears out, but for now I am very happy with the motion transfer of my current build.

Final Configuration

I eventually got rid of my SleepOnLatex mattress cover because it was honestly pretty useless at keeping the layers aligned and just made it harder to rearrange them every couple months when it became annoying. And then I threw out the HD36-HQ foam because it made the bed an inch taller for no reason.

Notably, for about a month I tried sleeping on just the latex and memory foam, because I really liked the idea of a minimalist mattress, but it turns out the 4” support layer really is useful, not just for bottoming out when kneeling, but also for general comfort.

Ultimately I kept the original build, minus the cover and 1” layer. The final cost of what I kept for a king sized mattress was $763.

One Year Review

So, do I like my mattress? Well, it has now been almost a year and a half since I built it, and the tldr is that it is fucking awesome. Building my own mattress has literally transformed my life: I’ve lost 30 pounds, read 120 books in one year, and my mother even got that grandkid she wanted. I mean technically this is because I went on a diet, downloaded audiobookshelf, and my sister had a baby, but who’s counting?

Advice

If you want to build your own mattress, I had very good experiences with both SleepOnLatex and FoamByMail, and I highly recommend my final configuration.

If you need a softer mattress you have two options: you can make the layers thicker, or you can go with a lower ILD, perhaps swapping my 29 ILD transition layer for a 20 ILD.

If for some reason you are on the fence about building a mattress, don’t be. There really aren’t any meaningful downsides I can think of, and the end result will almost certainly be higher quality and less expensive than traditional options.