Well I’m going for it. I’m adventuring into the land of mattress surgery to convert our Stearns and Foster “Heirloom” to a Dunlop latex/pocketcoil hybrid. Thanks for providing such a great place for sharing the knowledge on this topic. While I have several questions, I’m looking for any general guidance on the process or layer selection given the original mattress was quite comfortable.
Unfortunately it only lasted ~7 years before starting to lose support. I still get a very good sleep in the middle of the mattress away from the normal sleep zones but that only happens when my wife is away. I’m a back, side and front sleeper, ~190 lb. My wife is predominantly a side sleeper ~165 lb. The loss of support means a stiff back for me many mornings. The areas with lost support have almost no impressions but can be felt when pushing on the mattress. I think Phoenix describes these as ghost or virtual impressions.
Our mattress has no pillow top and is labelled by S&F as a firm mattress. The coil springs height is ~6.5" with 1" of polyfoam below and ~5.25" in 6 layers of mostly polyfoam above. ~12.75" overall.
Side note: On deconstruction, I found one mickey mouse layer of 3/8" latex but only in the middle third of the mattress. Hard to believe it’s cheaper to glue polyfoam to the latex than put in a full sheet of latex in. According to Sealy, this is equivalent to the S&F Garden Gate sold at the Brick here in Canada.
To get by, I have cut off the 3/8" polyfoam layers adjacent to the latex and put one of them back on top of the latex to boost the middle section.
Attached are photos of my mattress. I have included more than necessary but they might be educational to someone who is up for the same adventure.
My basic questions:
Aside form the possibility of somehow reusing the existing ticking, is there any benefit to using thicker or multiple layers of Latex to get back to the original mattress thickness? The foam in the ticking is soft in the sleep zones so will have to be removed.
Is 6.5" of S&F Intellicoil spring a reasonable starting point?
I note that the Avocado Green is the highest rated mattress from Consumer Reports and if they shipped to Canada, I don’t think I’d be posting this message. Their mattress has a firmness rating of 7 by CR which is one of the firmest in their tests. Originally I was planning one or two layers of 30ish ILD Dunlop but the Avocado only uses one 2" layer of D65/ 14-19 ILD. However, Arizona Premium labels 20-24 ILD as plush, 25-29 ILD as Medium and 30-34 ILD as firm. Comments?
The top encasement of the coil springs is a 1.5" thick layer of polyfoam that is glued to the sidewall polyfoam encasement. If I remove this, do I need to glue something in its place? Can the latex go right on top or should I place a layer of something in between?
My more in depth questions:
Latex hybrid mattresses seem to have one, maybe two layers of foam on top. Why is it that mattresses like mine have so many more layers? With seven layers above the coil springs, is there some general mattress theory that might explain some of this layering? I suspect this is somewhat beyond the technical level of this forum.
The bottom encasement is a layer of polyfoam. Should I be concerned about replacing this layer? I see Avocado uses 1" of D65/14-19 ILD Latex but most shops do not seem to sell 1".
I am considering a zippered mattress ticking with quilted wool for breath-ability. Will the wool in this style of cover get compacted in the sleep areas?
Should the height of the new ticking be shorter than the stack height of the mattress components? By how much?
Here are the rest of the photos. For some reason, they will not show on my computer but they will show up on my phone. Hopefully they will be visible to others.
Quite an adventure in the lands of “mattress surgery”! I see you are approaching this in the spirit of "adventure "which is always the best place to start. I am glad to hear that you have found both the forum and the site useful.
It’s worth mentioning that attempting to build something that is closely matching your previous mattress (when it felt “quite comfortable” can often a frustrating and futile attempt especially as you are considering different materials and also if you are trying to do this on your own, so I am glad you are looking for some guidance. I’d respond here to your initial questions but you’d be better off approaching one of our experts on their dedicated forum when it comes to deep dive in fine-tuning. You probably came across post #9 here the different ways that one mattress can “match” or “approximate” another one talking about several reasons why this can be difficult. In your case, the mattress rapid “aging” and breakdown of lower quality foams resulted in sagging. This happened over time which makes it difficult to pinpoint the moment when it turned from sleeping well to not sleeping so well and any ratios of break down/comfort. Also, within your 7 years, your body changed with normal aging and also tried to adapt and compensate for lack of support and alignment. (Your lower back pain in the morning is a good indicator of alignment issues).
Every individual layer and component you may choose for your mattress rebuild (including the cover, FR barrier, any quilting material, and of course all foam layers) will affect the feel and response of every other layer and component both above and below it and the mattress “as a whole” so you would need to carefully assess the design and the specs of each layer combination.
This is correct. The term I use is “virtual” or “phantom” body impressions, where impressions don’t show up when measured by someone testing for a warranty challenge, but the excessive softening of the foams in the area where you sleep is felt when lying upon the mattress.Virtual/ghost impressions in the mattress are caused by a premature breakdown of materials in your current mattress, and likely the culprit of your back pain.
The thickness of a mattress is much less important than the specifics of what is inside the mattress and which specific design is the best match for you in terms of PPP.(Posture and alignment, Pressure relief, and your Personal preferences) There is more in post #14 here about the potential benefits of thicker individual layers The mattress itself. 8" - 10" is inside the range for the thickness that would allow for a suitable design for the large majority of people.
The benefit to using latex in replacing the polyfoam layers of the original mattress is an increase in durability and responsiveness. It’s also a great material when considering lumbar and back support. As you’ve likely already read, latex is very elastic which gives it the ability to instantly form a pressure-relieving cradle that takes on the exact shape of the body. This means that in its softer ILD’s it has a pressure-relieving ability that is superior to most other materials and very similar to that of memory foam.
That said, higher densities of HD polyfoam or HR polyfoam can be a good, slightly less expensive alternative to latex in a core layer for those who are on a more restricted budget and are looking for a good quality foam mattress core.
Yes, this is a good support layer for a DIY mattress. Coils are rarely the weak link in a mattress. and a very good support layer.
You are comparing different products (Avocado & Arizona Pr) different thicknesses, components, and even foams of the same type and ILDs from different sources will feel different (given everything else is the same. There are many interconnected variables involved In building our own mattress and it is impossible to predict how a new layer choice would compare to your previous mattress even though the materials themselves may have similar properties they can be quite different in feel and firmness (for the same ILD) Dunlop and Talalay aren’t directly comparable in terms of firmness using only ILD numbers because there are several factors that can affect how soft or firm a mattress (or an individual layer) feels besides just the ILD of the material (see post #4 here )
I am not sure I understand correctly if the foam is on the sides, top, or both (your attached photos did not go through for some reason). Generally, provided that the fabric is strong enough to hold in place all components, removing the top foam should not be a problem however if on the side removing 3" of foam make the encasement lose and allow for the shifting of the layering.
Sometimes it is part of the design other times is making it thicker which in the eyes of the inexperienced mattress shopper equates with more comfort… reasons can vary. Theories are plenty but a mattress is only good as well it feels for any particular individual and as long as it maintains its comfort/support properties.
This is called a base/stabilization layer. Many mattresses do not have it and it is not an issue as long as the spring unit is intact and you have a good foundation under the unit.
If you chose to keep it here are some of the reasons, you’d want to have a stabilization layer
a. Provides a solid surface that enables the pocketed coil springs to “activate” and function efficiently.
b. Helps with stabilizing the mattress from any side sway.
c. Provides protection and functions as an insulator pad in foundations for cushioning steel and wood touchpoints, which makes the mattress compatible with most types of foundation designs.
d. It can be a cost-effective alternative to foam to increase mattress thickness
If you reuse it, I’d make sure is either in-tact or have it replaced. There are sources that sell 1" foam. You may want to check some of our Trusted Members that have 1" foams.
This is a good choice as soon as you decided on the overall thickness of your mattress. It allows for customization and any layer exchanges that may be necessary. Wool can have many effects on the latex underneath it depending on how thick, compressed, and/or densified it is and how soft it is relative to the foam underneath it. Over time as the wool compresses … it will have a greater effect on the foam underneath it as it becomes firmer. A wool mattress pad is also generally “softer” than a wool quilted mattress ticking because it isn’t an integral part of the mattress and will conform more to the layer underneath it. How well a wool quilted cover will conform to the latex underneath it also depends on the material that it is quilted to. The more stretchable the material (stretch knits for example as opposed to a damask cover which is woven) the better the latex can take on the shape of the body and the more pressure relieving the latex can be.
It depends if you keep the existing glued 1.5" foam and of its location. A good cover should be well taut with no slack to keep the layers secure in place. I’d take some good measurements with it taut if you decide to reuse it.
…. Without personal testing and going through the learning curve of becoming familiar enough with different types of materials and layering and how they work in combination with each other to predict how a certain layering may work for you … you would be much better off simply going with the suggestions of a knowledgeable retailer or manufacturer who is familiar with how the different options they offer fits the “averages” of people who may be similar to you.
Overall, there is no formula that can predict with any certainty what type of layering you may do best with that can possibly be more accurate than your own personal experience.
Hope it gives you some gear for the mattress adventure land.
Phoenix
Thank you for your thoughts Pheonix. I will be reaching out to Canadian suppliers of Latex.
It is interesting that the AG mattress uses a softness of Dunlop that I have not seen elsewhere. Is there a special supplier for that? Mario from MFC figures I will have a hard time getting close to the softness of the original mattress with Dunlop
One more try for photos. Trying Chrome this time…
Shows how the white liner is attached to the top. The liner goes down more than half way and was stapled to the foam encasement. There is another liner coming up from the bottom and stapled.
Opening the quilted top layer. For a non pillow top there is still alot of foam in there. Two layers of foam with synthetic batting on top.
The top layers of foam with the encasement just at the bottom of the photo. Oh! is that a skimpy 3/8" layer of latex foam I see? Read on. The bottom photo is peaking under the foam at the coils. The 3" wide foam encasement of the coils is in the foreground and was glued to the foam layer above.
This should be the most embarrassing photo for the people at S&F. Can it really be cheaper to piece this sheet together than just to put in a layer of 3/8" latex for the selling point?
Here’s hoping the photos come through.
Is there any way to gauge the ILD of the polyfoam other than a well trained hand?
It looks like the photos came through this time with no issue! I am glad I delayed responding to you as I enjoyed looking at the construction breakdown sketch. I can see that the foam perimeter around the coil unit would help provide for a firmer edge reinforcement.
AG have their own latex at a facility and with a supplier in southern India. It certainly makes for an interesting read that information here for you.
[quote] Mario from MFC figures I will have a hard time getting close to the softness of the original mattress with Dunlop
[/quote]
I agree with Mario, he’s got decades of experience working with foams! Talalay has a softer feel You can see a comparison between them in post #7 here but your own experience is really the only way to know which one you prefer with any certainty. You will “feel” more of the upper layers than the deeper layers … at least when you first lie on a mattress
With polyfoam … density is a “quality spec” and has little to do with the foam firmness. The density of polyfoam is the single most important factor in its durability but any density of polyfoam can be made in a wide range of firmness levels so you could have low-density firm polyfoam or soft polyfoam or higher density firm polyfoam or soft polyfoam. The specs that will have the biggest effect on the firmness of a polyfoam layer are the ILD/IFD of the foam (which would be the “simplest” method of comparison), the compression modulus of the foam, and the thickness of the foam.
Look forward to any updates you might have with the rebuild project.
Okay, I’m back with an update:
After some real world “testing” and more discussion, I departed a bit from Marios initial advice and went with a 3" layer of medium Dunlop from MFC. I found the soft Dunlop a bit too soft also wanted the natural/organic aspects of Dunlop. Despite all the layers of foam in the original mattress, it was called "firm". I ordered mid-November but shipping took a long time. With the Christmas season, it arrived finally on Dec 19th. Using my fingers and occasional use of a sharp Olfa style knife, I broke the glued connection from the side wall foam to the top foams then rolled up all the top foam layers and removed them. At this point, I used a straight edge to verify that the pocket coil springs were in good shape. I had already awkwardly checked them from the side but could now do a better job with the upper layers of foam completely removed. The new foam was placed on top and for the time being, I just placed the factory quilted cover back on top, tucking the non-woven cloth down beside the foam to hold it in place. Eventually the top will have to be replaced due to the minor depressions it is showing. My wife reports that it feels the same which I am calling a success. She did not notice the the depressions the way I did so Im not surprised. Her back is probably in better health. Unfortunately, the day of the install, I had a skiing accident which has injured my back and has meant very uncomfortable sleeps due to the injury so I am not quite in a position to make a final pronouncement. I am just now able to sleep on my back and so far so good.
I do have a couple of questions:
-The attached photo shows circles where the pocket coil springs have left indents of varying depths in the old polyfoam. I’m guessing that if I do nothing, I will end up with the same thing in the new Dunlop foam. My question is what should I put between the pocket coils and the Dunlop to protect the Dunlop and allow things to move properly?
-Should I worry about the bottom very layer of foam under the pocket coils and if so what would be a suitable long term replacement?
Thanks for the update. I am glad to hear you found a Dunlop you like and that things went relatively well in removing the existing foam layers. Thanks for sharing the process.:cheer: :
Sorry to hear about your back injury during skiing, but if I’m reading correctly, you’ve been having some success sleeping on your back recently and your wife is sleeping well on the reworked mattress, which means that you are either spot-on or moving in the right direction.
Mattresses that use pocket coils with a higher coil count that are surrounded by a fabric don’t generally need an insulator (although some may still have one) to prevent the padding materials from pocketing into the coils. You could use some type of non-woven material such as densified or bonded polyester or cotton fibers or resinated textile clippings or coconut coir or flexible mesh material to prevent the forming of indentations mostly due to any rubbing or mechanical stress the foams are going thorough at the steel touchpoint.
This is called a base/stabilization layer. Many mattresses do not have it and typically it is not required as long as the spring unit is intact and you have a good foundation under the unit. It is a think layer furthest away from your body and will have little to no effect on the general comfort/support provided that it is still in good condition.
I’d keep in mind some of the “theory” behind having a stabilization layer at the bottom of your unit to help with your decision to keep it or replace it.
a. Provides a solid enough surface that enables the pocketed coil springs to “activate” and function efficiently.
b. Helps with stabilizing the mattress from any side sway.
c. Provides protection and functions as an insulator pad in foundations for cushioning steel and wood touchpoints, which makes the mattress compatible with most types of foundation designs.
d. It can be a cost-effective alternative to foam to increase mattress thickness
If you reuse it, I’d make sure is either intact or have it replaced with some Densified Fiber, or Polyfoam There are several sources that sell 1" foam, and you may want to check some of our trusted members that provide 1" polyfoams.
Good progress! I am looking forward to any additional updates!
[quote=“Searing” post=86785]
I do have a couple of questions:
-The attached photo shows circles where the pocket coil springs have left indents of varying depths in the old polyfoam. I’m guessing that if I do nothing, I will end up with the same thing in the new Dunlop foam. My question is what should I put between the pocket coils and the Dunlop to protect the Dunlop and allow things to move properly?
-Should I worry about the bottom very layer of foam under the pocket coils and if so what would be a suitable long term replacement?[/quote]
Searing, great job documenting everything in your project, looks like you’re off to an excellent start. It’s definitively a journey to get something that works perfectly for you but the reward of being pain free makes it all worth it in the end.
Having been through this exact same situation myself i have a few suggestions to add to what Phoenix mentioned:
I would look at some sort of heavy batting to insulate the coils if you want this to last a while. Over time pocket coils seem to compress the comfort layers far worse than the old Bonnell spring design they used for decades. This seems to be why beds often feel good in the store but only after a few months this changes rather quickly. Using an insulator will change the feel of the mattress (making it stiffer) so you need to be careful with how it works together with the other pieces of the mattress to give you the feel you’re looking for. You could also try a layer of very thin neoprene (I never did this myself but it might work out well). I even tried a layer of thin flexible plastic (in my case a hockey shooting pad) but I just couldn’t get it to be comfortable for me. I ended up swapping out the coils for something else but you may need to do some experimenting to see what works best.
I wouldn’t worry too much about the stabilization layer, I did not find it to affect the comfort of the mattress much as long as you have a stable base (platform or box spring) on which the coils can push against.
As a reminder, after mattress surgery I had been using:
-top cover with quilted batting and polyfoam (reused)
-3" medium Dunlop (new)
-6.5" S&F Intellicoil with polyfoam perimeter (reused)
-1" polyfoam original stabilization layer (reused)
-bottom cover and sides (reused)
As of last week, we are not using the top quilted layer. The sleep zones were still just not as comfortable and supportive as the middle unused section. Of course, the change made the mattress a bit firmer and much less visually appealing as the fancy ticking is now removed. However, the support across the mattress is now comfortable and very even, I am awaking with less back soreness and my wife is still sleeping well.
Prior to this change, a straight edge showed body impressions at the top of the cover of ~1/4". There were very slight impressions at the top of the Dunlop (1/16") and the top of the springs (1/16" or less). I’m guessing these slight impressions are the polyfoam stabilization layer getting impressions from the springs or possibly losing support.
Still up for debate:
-add a top comfort layer of soft Dunlop before buying a new encasement? Time will tell.
-replace the stabilization layer? Probably needs more surgery to tell if it’s just coil impressions or foam failure. Probably not worth the effort.
-while I’m not seeing significant coil impressions yet, what to put between the pocket coils and the Dunlop to protect the Dunlop over the long term.
Not necessarily looking for answers, just letting folks know where I’m at. At the same time, comments are welcomed.
There were a few suggestions of materials to use between the coil tops and Dunlop but several of the ones suggested by Phoenix I’m not familiar with. If anyone could post some links, it would be appreciated.
A thought I had was to hot glue individual squares of thin hard plastic to the tops of the coils which would still give them their independent behaviour while protecting the foam. Probably more work than it’s worth though.
Thanks for sharing your DIY Adventure updates . Good work on your surgical experiments, it sounds like you’re heading in the right direction with the layering configuration. Glad to hear that the support across the mattress’s surface has improved and that you both are enjoying better sleep. No further comments here, just wanted to say Hi and Keep on Keepin’ On…
While I have several questions, I’m looking for any general guidance on the process or layer selection given the original mattress was quite comfortable.
