Replacing Dunlop latex foam with high resiliency/density polyurethane foam


I moved from my home state to another state several hundred miles away for work, thinking it would be more temporary. So now I’ve been sleeping on an not very comfortable spring mattress since then. My previous mattress, I ignorantly bought primarily off of reviews on Amazon & bought it from Amazon as well. I actually liked that medium firmness memory foam mattress. It actually was an upgrade over the previous all latex mattress that was a solid 8” max. slab of medium soft firmness.

Anyways, recently I’ve been researching products I buy way more thoroughly than I used to. Here’s what I came up with.

*DIY = do it yourself *HR = high resilience *HD = high density

I have found a DIY build & through a member company listed here & discussed the build via phone with them. So now I have a planned mattress configuration build that I’m fairly confident will work for my weight/ height/ BMI/ sleep style/ personal preferences.

It’s as follows: All layers use >95% all natural dunlop latex foam. 5” base/foundation (core) layer firm (38 ILD). 3” support layer (28 ILD). 2” top comfort layer (19 ILD). I intend to hold off on buying the top layer until I give the mattress a good test run, as I might not even need it. This mattress is intended to be slept on one side only.

I could purchase this today, as I believe I found good quality dunlop latex for likely the most reasonable price out there (it’s with the same company I discussed this build with). However, I found a good quality high density foam at well under half the price for that 5” base/foundation (core) layer & a few other HR/HD foams as well that I haven’t counted out as possible replacements. The comfort/support layers would still remain the dunlop latex.

What I’m not positive on, is how the ILD #’s & firmness given for dunlop latex equates to the IFD #’s & firmness given in HR/HD polyurethane foams. I see different companies rate their >95% all natural latex typically between 38-44 ILD = firm. Then I see the HR/HD foams typically rated firm = 45-50 IFD.

I believe from what I’ve researched, that the ILD & IFD #’s are quit similar when it pertains to how they relate to the foams I mentioned in this post. If so, that means I should get an IFD # approximately equivalent to the 38 ILD. That way I get the proper support, regardless of the firmness feel. I value support over comfort, which probably won’t even be felt, being buried beneath 3-5” of support/comfort layer. So I believe I should target a 38 IFD HR/HD foam to replicate the 38 ILD support of the dunlop latex, even if the firmness feel isn’t exactly replicated. Three of the companies in the running have 38, 40, & 41 IFD #’s. The other 2, including the front runner have either 35 or 45 as options. So 35???

I just would like to know if I’m thinking along the right lines with all this. If not, please set me straight & maybe there are better options that I’m overlooking as well. I’ve only been researching mattresses for one week.

Hello Jayton,

Thanks for reaching out to Luma Sleep via The Mattress Underground. Seems like you know what you want/need and have done lots of research. Congrats!
Yes, IFD and ILD are essentially the same in the measurement process and results. IFD/ILD is a different physical property than hardness/firmness (also referred to as a durometer reading in the rubber world. )
Assuming you are looking for the HR/HD polyfoam for the 0.5" base, you should not have an issue with any of the samples. Our preference at Luma Sleep if for the underlying layers to be progressively firmer, but that is not so much an issue in the function/application you are solving.

Goof luck with your DIY. Our guess is you will add the 19 ILD comfort layer.

Hope this helps!

Team Luma

Thank you for your response. With my lack of experience, I just want to make sure I’m going about this build the right way.

Yes, the HR or HD foam layer that I’m planning in this configuration, is the 5” base/foundation layer of the mattress & my intention is to go with the more premium dunlop latex in the support & comfort layers 5” as well.

Base layer 5” of 35 to 41 IFD HR or HD foam, support layer 3” of 28 ILD latex, & comfort layer 2” of 19 ILD latex.

Looks like a well thought out and logically engineered design. Congrats. We hope it sleeps as well.

Sweet Dreams,

Team Luma

After reading some DIY builds resulting in unsatisfactory results, I will be waiting for mattress stores to open, test out some mattresses to see what works for me & go from there. My current mattress isn’t great, but I’m not hurting from it either.

A key challenge with a DIY build is when you are designing a mattress that is not the same as one designed by a major mattress manufacturer. Most major mattress manufacturers life cycle test their mattress designs in addition to pressure mapping etc. DIY tends to be a trial and error process unless you have the specs for the mattress you want and intend to replicate it. As a wise teacher once told me, “haste makes waste”. As long as you have the benefit of time, no need to jump into a process where you still have high uncertainty.

Sweet dreams,

Team Luma

Yeah, I want to see what materials I’m working with prior to purchasing them.

I was thinking of going with a 9” mattress instead of 10. Was wondering if it would feel any different? I can see needing the thickness for a larger person, but I’m 175 lbs.

I originally wrote of using talalay after find a few all natural latex companies trashing it. However, I decided to look more into it & now want to use the blended Global Talalay ILD 19 for the top 2” of the mattress. It sounds like it competes in durability with the Dunlop I was planning on using, it’s a cooler material to sleep on, & it’s lighter to sleep on, though even though it provides the same support.

For the middle layer, I would still go with the 3” dunlop 28 ILD. The bottom would change from a 5” high density foam (35 ILD) to 4”.

TOP LAYER: 2” blended Global Talalay (19 ILD)
MIDDLE LAYER: 3” +95% Dunlop latex (28 ILD)
BOTTOM LAYER: 4” High Density 2.6 lbs Ultra polyurethane foam (35 ILD).

Cover 9” all natural cotton knit & bamboo with zipper. Supposedly no Polyester, Rayon, or other man made materials. Also, It lets the mattress breath unlike those 1” cotton & wool ones that totally negate the cooling abilities of the mattress. Bamboo is supposedly cooler than wool anyways. The downsides are it’s not waterproof or machine washable. I had that cover scopes out prior to the my first post, just didn’t mention it.

Your thoughts on whether the 9” vs 10” I originally planned would be appreciated. Or any thoughts on any of the materials I plan on using.

Hello Jayton,

Thanks for reaching out to Luma Sleep! All of the materials you are using are high-performance foams, so 9" or 10 " will both work well. You may want to start at 9" and then, if needed, add the other 1". We would expect this to be in the top Talalay Comfort layer or in the middle support/transition layer. 4" of 35 IFD 2.6# polyfoam is an ideal amount. The one thing you may want to do is not purchase the cover until you finalize the design.

Hope this helps!

Team Luma

Hello & Thank you for your reply.

Sounds as if I should reconsider the 5” comfort & support/transition layers as being inadequate. I’m quite hesitant about the 3” comfort layer, just from talking to Ken a rep from Arizona Premium & backed up by Latex Mattress Factory (based on my weight category), that if I go with 3” soft comfort layer , that I should then go with firm on the rest of the mattress. I like the idea of having a support/transitional layer too much to do that.

I can recall from prior research, that you should have a 5”-7” combined comfort & transitional layer. So 6” sounds like a good idea.

So with your suggestion, I would go with:

Top/comfort layer: 2” Blended Talalay (soft firmness) 19 ILD

Middle/Transitional/Support layer: 4” +95% Dupont Latex (medium firmness) 28 ILD

Bottom/Base/Foundation layer: 4” 2.6 lbs High Density Polyurethane Foam (medium firmness) 35 IFD

Hello Jayton,

We are not suggesting any changes to you. Luma Sleep tests its mattress designs. Luma provides customers with a free comfort exchange option as we do not know their exact specifications nor how they will interact with a Luma Sleep mattress model, which is designed for 90% of the population.
We are not DIY specialists. To Luma, DIY is trial and error. Much of your personal design should be influenced by your personal specifications of height, weight, body shape, sleeping positions, comfort preferences.
It seems you are getting input from several other TMU members that specialize in DIY. We defer you to them as they are experienced in the DIY micro-segment.

Good Luck,

Team Luma

I think I will go with a combination of their advice & my past experience sleeping on latex & memory foam. The latex though was wasted money, because I got the wrong configuration ( did zero research). The memory foam I got, I believe was 3” medium over a firm foundation/base layer. I found it slightly too firm.

As said earlier, I will also wait until the foam is available to check out in person, to feel out the materials I planned to use. I’m thinking I will just go with the 10”, even though slightly more expensive. It sounds risky to try to skimp out on any of the layers. That 1” of high density foam is quite cheap anyways.

Seems like you have done your research this time around and that you have a well thought out design and plan.

Sweet dreams,

Team Luma