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normal Building a Mattress: Have a few questions

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12 Sep 2017 22:03 #1 by androiddd

Hi everyone,

I've been reading this forum for a long time, but this is my first post.

I'm in the process of designing and building a new mattress, and also trying to improve a formerly built DIY mattress. We are both back and (sometimes) side sleepers.

Let's start with the previously built one, which was a Queen mattress for a guest room. Everything was from Foam Factory. The layers are, from bottom to top, 5 inches of http://www.foambymail.com/LR_2/lux-r-foam-mattress.htmlLUX-R poly foam as a support layer. This foam has a 1.8-pound density and has an ILD of 50. Next up was a layer of 5lb http://www.foambymail.com/V_5/5lb-memory-foam-topper.htmlViscoMax Memory foam , 3 inches. This combo didn't work because although the 5-pound memory foam is very nice, we would bottom out against the very firm poly foam support layer. We then added a 2 inch soft Talalay latex memory topper underneath the memory foam which improved things but still we ended up bottoming out. After discussing this with the Foam Factory, they pointed out that we probably made a mistake by starting with the Lux R foam, and suggested we buy a 5" piece of their http://www.foambymail.com/HDHQ_2/hd36-hq-foam-mattress.htmlHD 36 HQ foam, which has a softer feel with an ILD of 35 And a density of 2.8.

Here's my question: although I am sure that buying the softer support foam would hopefully fix the feeling of a hard bottom to the mattress, it means tossing out a perfectly good piece of support foam and spending more money. I'm curious if anyone has any good ideas about an intermediate layer of foam which would sit between the 3" 5-pound memory foam on top and the very firm support foam on the bottom. Options might include a two or 3 inch http://www.foambymail.com/LTX_T/dunlop-latex-foam-topper.htmlDunlop latex layer, or perhaps a medium firmness regular poly foam in a two or 3-inch layer. Obviously, the poly foam would be much less expensive. Or should I just toss the firm support foam and start with the medium support foam?

The main bed build will also source most of the components from the Foam Factory. It would start with a 5 inch layer of medium firm poly support foam, the HD 36 HQ foam with an ILD of 35.

The challenge for this mattress is that it needs to work for a 205 pound 5 foot nine man as well as 115 lb. 5 foot three woman. So it might involve some split layers.

The transition layer might be 1 or 2 inches of medium firm Dunlop latex, with an ILD Of 29. This should allow the heavier one of us not to bottom out against the support foam. Input as to whether one or 2 inches would be preferable would be great. I'm not sure that 1 inch would be enough of an intermediate layer to stop me from bottoming out.

The top comfort layer could either be a simple 3-inch layer of 5 pound Visco memory foam, or could be two individual 2" layers of 5lb and 4lb Visco memory foam. The advantage I see of splitting the comfort layer into two layers is that they could be swapped from up and down to change the firmness slightly.

All of this will go into a mattress case with the zipper. Initially I would build this as a single, un-split mattress, but if necessary would cut some of the layers longitudinally to allow some customization for each sleeper.

Any input would be great. I know this is a little bit complicated, but I like to fiddle, and having tried a variety of other bed in the box memory foam mattresses that friends have purchased, I haven't been impressed with most of them. I also like the option of replacing foam layers, especially in the comfort layer zone, as they wear out, rather than having to toss an entire mattress.

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13 Sep 2017 12:38 - 13 Sep 2017 12:39 #2 by Phoenix

Hi androiddd,

I've been reading this forum for a long time, but this is my first post.


Welcome to the forum! :) I’m glad you’ve found us and have taken the time to contribute.

I'm in the process of designing and building a new mattress, and also trying to improve a formerly built DIY mattress. We are both back and (sometimes) side sleepers.


I’m not sure if you’ve found it yet, but some of the better comments and links I have for designing a DIY mattress are listed after Option #3 in this post . Even if you were extremely knowledgeable about foams and mattress design, there is quite a bit or trial and error that can go into designing your own mattress, but some people (such as yourself) enjoy “tinkering” and derive satisfaction from your own personal creation.

Here's my question: although I am sure that buying the softer support foam would hopefully fix the feeling of a hard bottom to the mattress, it means tossing out a perfectly good piece of support foam and spending more money. I'm curious if anyone has any good ideas about an intermediate layer of foam which would sit between the 3" 5-pound memory foam on top and the very firm support foam on the bottom


I wouldn’t be able to tell what material might work best for you, but it does make sense that you are “feeling through” the 3” of memory foam and then the 2” of “soft” (you didn’t mention the ILD) Talalay latex to the firm polyfoam core. I would expect that in this combination you’re going to “feel through” to just about anything placed underneath, as memory foam itself isn’t a very supportive material nor does it show much resilience (rebound). Keeping the firmer polyfoam core and then the upper 3” of memory foam, a more progressive construction using a more “medium” latex (such as the Dunlop you mentioned) or a good density (1.8 lb minimum) polyfoam in the “medium” range could work as a better transition layer, better matching the compressed feel of the memory foam on top instead of being closer to it in feel than the plush Talalay latex was. There’s more detail about typical “progressive” construction you should read in this article . There’s certainly no reason that using the firmer polyfoam support core wouldn’t work for you, but I think that even if you chose the softer polyfoam core that you’d still want to consider a more “medium” transition layer as you described, so logically you may wish to begin with this and then perhaps decide if you wish to change to a different support core.

The main bed build will also source most of the components from the Foam Factory. It would start with a 5 inch layer of medium firm poly support foam, the HD 36 HQ foam with an ILD of 35.


If the “main bed” is also a queen like the guest bed, why wouldn’t you buy this polyfoam core at the same time as the transition foam for the guest bed and then have all of that to play with? Just a thought.

The challenge for this mattress is that it needs to work for a 205 pound 5 foot nine man as well as 115 lb. 5 foot three woman. So it might involve some split layers.


That’s easy enough to do with an electric meat carving knife after the fact, should you desire to customize the transition and uppermost foam layers within the mattress. That’s one of the nice things about an all-foam DIY project.

The transition layer might be 1 or 2 inches of medium firm Dunlop latex, with an ILD Of 29. This should allow the heavier one of us not to bottom out against the support foam. Input as to whether one or 2 inches would be preferable would be great. I'm not sure that 1 inch would be enough of an intermediate layer to stop me from bottoming out.


While I understand what you “mean” by “bottom out”, I want to comment that you won’t be compressing the foam to it’s minimum thickness. All of the foam layers of a mattress work together, not individually or sequentially, so you’re desiring something in the transition layer that matches better with the “compressed ILD” of the uppermost layer so that this transition from the comfort layers to the base foam isn’t so abrupt, if I understand this correctly. You’re correct that only 1” of latex probably won’t have as much impact as at least 2” of the “medium” Dunlop that you are considering in this case, and something like this is certainly a common choice used by many mattress manufacturers.

The top comfort layer could either be a simple 3-inch layer of 5 pound Visco memory foam, or could be two individual 2" layers of 5lb and 4lb Visco memory foam. The advantage I see of splitting the comfort layer into two layers is that they could be swapped from up and down to change the firmness slightly.


I think in these scenarios, if splitting, I would consider splitting the memory foam layer(s) as well as the Dunlop latex “transition” layer. This could give you options for moving the latex up or down in the order of comfort layers, as well as allowing you to place different ILDs of latex on each side.

In the scenario using two different 2” memory foam layers over the latex transition layer, this of course would allow for more comfort “tinkering” by moving the latex layer up within the ordering. But rearranging the two memory foam layers (4 lb and 5 lb) on top of each other in the #1 and #2 positions won’t have as much of a noticeable difference in comfort, especially once your body temperature has impacted the viscous nature of the memory foam after 10-15 minutes. All memory foam is relatively soft (in the low to mid-teens for ILD), and while there are subtle differences in feel, responsiveness to heat, rebound and speed of viscosity change, it would be minor in perception as compared to different ILDs in latex or poly foam.

As I think you’re already aware, I can’t predict what might feel “best” to you, but only comment upon the ideas you’re considering. In the end, as I think you’ve already discovered, only your own personal testing will be able to determine if what you’ve constructed will meet with your personal comfort preferences, so hopefully some of my comments here have bene helpful.

And while I know you’ve been dealing with Foam Factory (aka Foambymail or FBM and other names as well) you may still want to read this post and this post and this topic (about their polyfoam and sources) and this post (presumably from a past employee) if considering anything else from them and some of the information and sources of their foam products.

Phoenix


Researching for a mattress?... Be sure to read this post first.
Last Edit: 13 Sep 2017 12:39 by Phoenix.

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14 Sep 2017 13:52 #3 by androiddd

I have a Ph.D. in psychology but I think Phoenix, you should be awarded an honorary Ph.D. in Mattressology! What a thoughtful and deep reply.

I have a few questions.

1. What is high resilience foam and where does one buy it?
2. I read your other article about progressive layers, and it sounds like since we are both side sleepers at least part of the time, we would need a comfort layer on top of 2 inches, and then an intermediate layer of 2 to 3 inches. Perhaps a 2 inch 5 pound memory foam on top, followed by a 3 inch layer of Dunlop latex in a medium firmness. The memory foam tends to have an ILD of 14 or so so I'm wondering if the Dunlop should be 20 or more like 29 ILD as the progressive layer?

3. If I don't want to spend the money on the Dunlop latex, which costs about $100 per inch and a queen size, what kind of poly foam would you recommend for that intermediate layer? Should be flat foam or convoluted foam? Should it be high resilience foam? Particularly on the guest bed that I'm rebuilding, I want to keep the price down.

3.5 I see what you mean about not splitting the comfort layer between 5 pound and 4 pound memory foam as they probably both feel pretty similar. I do wonder if it would make sense to split the bottom support layer into ILD 29 and ILD 50 pieces, perhaps 3 inches thick for each? I would assume the 29 firmness should go on top. But they could be swapped later if necessary. I may be overthinking this :-)

4. Not a question just a comment. I have used Foam by Mail before and other than slow shipping I haven't had problems. As far as I can tell their prices for memory foam are much lower than anywhere else, but if there's another vendor that has similar prices but better quality I would certainly be interested in knowing their name. For latex they seem to be more in the same ballpark as other vendors, with costs for Dunlop being about $100 per inch of thickness and the queen size. (Of course there are very high-priced latex vendors too, which almost double those prices.)

Most of the complaints that I read on your site seem to be about confusion between Dunlop and Talalay latex, but FBM no longer even sells any Talalay latex.

Anyway, I want to thank you from the bottom of my heart for such a smart response and this will greatly help me in planning this bed build. I'll be ordering the components over the next few days, and building the bed in about two weeks. I'll update on success or failure.

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14 Sep 2017 16:53 #4 by Phoenix

Hi androiddd,

I have a Ph.D. in psychology but I think Phoenix, you should be awarded an honorary Ph.D. in Mattressology! What a thoughtful and deep reply.


Thank you for the kind words!

What is high resilience foam and where does one buy it?


High resilience polyfoam is technically polyfoam with a density of 2.5 lb or above, with a compression modulus of 2.4 or above. It’s discussed in more detail here in this article . Some better sources of which I am aware for polyfoam are listed in the component supplier post here .

I read your other article about progressive layers, and it sounds like since we are both side sleepers at least part of the time, we would need a comfort layer on top of 2 inches, and then an intermediate layer of 2 to 3 inches. Perhaps a 2 inch 5 pound memory foam on top, followed by a 3 inch layer of Dunlop latex in a medium firmness. The memory foam tends to have an ILD of 14 or so so I'm wondering if the Dunlop should be 20 or more like 29 ILD as the progressive layer?


A 2” + 2” or 2” + 3” combination certainly could work well. The 20 ILD Dunlop would be closer in plushness to the memory foam, but might be more of an abrupt transition to the polyfoam base (depending upon which you choose). The 29 ILD Dunlop might “bend into” either polyfoam core better, but it could be a bit more of an “abrupt” transition between that and the upper memory foam layer. It all depends upon your personal preference. Remember that all of the layers work together to provide overall comfort, but the uppermost layers will have the greatest impact upon comfort perception.

If I don't want to spend the money on the Dunlop latex, which costs about $100 per inch and a queen size, what kind of poly foam would you recommend for that intermediate layer? Should be flat foam or convoluted foam? Should it be high resilience foam? Particularly on the guest bed that I'm rebuilding, I want to keep the price down.


If you want to keep the price down for the guest room mattress, for the transition you may want to consider 1.8-2.0 lb polyfoam. I personally would choose a solid sheet versus convoluted.

I see what you mean about not splitting the comfort layer between 5 pound and 4 pound memory foam as they probably both feel pretty similar. I do wonder if it would make sense to split the bottom support layer into ILD 29 and ILD 50 pieces, perhaps 3 inches thick for each? I would assume the 29 firmness should go on top. But they could be swapped later if necessary. I may be overthinking this


You certainly could do this, and yes normally the 50 ILD would be on the bottom with the 29 ILD on top. This would provide a more “gradual transition” to the deepest support layer. And if you do this, it would impact what you would choose for your upper transition layer. I always recommend a “bottom up” approach when analyzing these scenarios.

Not a question just a comment. I have used Foam by Mail before and other than slow shipping I haven't had problems. As far as I can tell their prices for memory foam are much lower than anywhere else, but if there's another vendor that has similar prices but better quality I would certainly be interested in knowing their name. For latex they seem to be more in the same ballpark as other vendors, with costs for Dunlop being about $100 per inch of thickness and the queen size. (Of course there are very high-priced latex vendors too, which almost double those prices.) Most of the complaints that I read on your site seem to be about confusion between Dunlop and Talalay latex, but FBM no longer even sells any Talalay latex.


If you read through all of the comments on the forum about them, you’ll see that there was more than what you mentioned. What I believe to be Dunlop represented as Talalay, evasiveness with specifications, uncertainty about sources, repetitiveness of support factor numbers (questionable specifications)...(from one of my previous posts) There is more but I think you catch my drift. I won't support a business which I believe follows less than ethical (by my standards) business practices and they have a long way to go and a lost reputation to make up for before I would consider buying any of the latex foam they sell or suggesting anyone else does. There are many who "love" them ... but I believe that is only because they don't really know what they actually purchased. There are also many more who don't ... and with good reason. If you choose to deal with them that’s certainly your prerogative, but I’ve been pretty clear regarding my position for the reasons stated here and elsewhere on the forum.

And to repeat what I posted earlier, some better sources of which I am aware for latex and polyfoam are listed in the component supplier post here .

Anyway, I want to thank you from the bottom of my heart for such a smart response and this will greatly help me in planning this bed build. I'll be ordering the components over the next few days, and building the bed in about two weeks. I'll update on success or failure.


I’ll look forward to your updates. And there are no failures…just steps along the learning curve.

Phoenix


Researching for a mattress?... Be sure to read this post first.

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25 Oct 2017 12:14 #5 by androiddd

Hi Phoenix,

Quick question on adding a layer to a mattress build that Almost Works.

The build is this, from bottom to top layer.

Bottom: A very firm latex mattress, probably about 10 years old, in good shape and not sagging at all but way too firm. Not a pillowtop.

Next Layer: 3 inches of new 5 pound density memory foam.

Next and top layer: 2 inches of a fairly soft talalay latex topper. It's one of those dual layer toppers with 1 inch of slightly firmer foam and 1 inch of softer foam. The softer side is up.

Here's the problem. The current configuration feels very supportive, but needs a little additional pressure relief. Both my partner ( 115 pound woman) and I (205 man) find that we toss and turn quite a bit on the current set up. My experience of it is that I'll be on my back for a while, then I'll turn on one side, then my shoulder will start hurting so I will turn back on my back and so on. Both of us wake up feeling a little bit beat up.

We've tried having the memory foam on top of the latex layer but then we tend to sink into much, so the support is not adequate.

What you think might help? Ideally if I could add a single layer of something to get a little additional pressure relief, that would be great. Alternatively, I'm not that invested in continuing to use the 2 inch latex topper (it could go elsewhere) so if there's a alternative that would get us both pressure relief and not bottoming out onto the way too firm latex mattress underneath, that would be great.

Options might include some soft poly foam on top, or perhaps 1 inch of memory foam. Open to other suggestions as well.

Also, here's what I have access to stealing from other beds in the house.

2 inch memory foam, probably three or 4 pound density

3 inch soft Dunlop latex topper

Thanks for your help with this it's been vexing me every morning. The bed is so close to being perfect. But oh so far!

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25 Oct 2017 15:24 #6 by Sweet Dreams

Not Phoenix here, but based on your described issue and what you have available on hand I'd suggest trying the 3" soft Dunlop topper in place of the 2" soft Talalay topper. The additional inch added to your comfort layer may give you the pressure relief you're seeking and it should be relatively easy to try. Once you see how that feels even if it isn't your ultimate solution it may help determine how to better achieve your desired feel. Good luck with your project!

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25 Oct 2017 17:58 #7 by Phoenix

Hi adroiddd,

I would try combinations with what you have available to you first. Sweet Dreams had a good thought up using the plush Dunlop topper in place of the thinner Talalay topper. Another thought would be try the firm mattress, then place on top of that the memory foam, then place on top of that the Dunlop topper, then the new plush Talalay topper on top of that.

I’d be interested to learn your results trying out those two different configurations.

Phoenix


Researching for a mattress?... Be sure to read this post first.

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