A problem I had with ZONING my mattress
Feb 23, 2008 10:08 PM
Location: L.A. area
Joined: Jan 18, 2008
Points: 1161
As most of you know I have been experimenting with my mattress which basically consists of, top to bottom, top 1/3 zone to middle 1/3 zone:

TOP 1/3 of mattress (shoulder area)
1" soft PU foam
1" medium HR foam
2" soft visco foam
springs

MIDDLE 1/3 of mattress (hip area)
1" soft PU foam
1" medium HR foam
1" very firm HR foam
1/2" super firm HR foam
springs

This is my current configuration which seems to work pretty well so far, though I'm still experimenting.

But at first the zones I had made were killing my back and I figured out why:

On the next to top layer, under the soft pu layer, I had different densities of foam so there was a line right at my waist which was the division between, say, a medium one
inch layer and a firm one inch layer. So that "line" where the medium piece met the firm piece was actually creating a pressure point or line of pressure all the way across
my waist, or above my waist (25" down from the top of the mattress).

What I realized is that I HAVE to have the same density of foam on that top layer (next to top layer, not counting the topper, it's the top layer). Otherwise I was getting a line of pressure across my waist from the difference in densities. I assume I also need to have the topper be an even firmness all the way down the length of the mattress.)

So once I began using Medium firmness or medium ILD for that next-to-top layer for both my top 1/3 and the middle 1/3 of my mattress, that pressure line disappeared and
now I am doing much better! I still have a much softer top 1/3 for my neck area, however, by making the layers UNDER the top layers be much softer for my shoulders.

This may not be true for everyone, but it was certainly true for me!

Hope this might help someone who is zoning. I'm curious if anyone else has ever run into this problem.

Re: A problem I had with ZONING my mattress
Reply #2 Feb 24, 2008 5:48 PM
Location: L.A. area
Joined: Jan 18, 2008
Points: 1161
I think most of the zoned commercial mattresses I've seen make the top 1/3 smaller and the middle 1/3 bigger. But I decided to divide it into 1/3's so as to give me the maximum number of pieces of foam to interchange. Likewise, I don't think it's necessary to zone the bottom 1/3 at all, but having it cut into 1/3's gives me those extra 1/3 pieces at the foot section to interchange with otther areas as needed.

While I have more foam at the top, it is so soft that it tends to be almost even looking by the time I put the fitted sheet over it. The visco I have at the top section is so soft that it mashes down to nothing. I think it is a challenge, however, to not have too much soft foam even there, or to not have enough - to get just the right amount, which may in fact be more height than the middle section due to the extra softness. I'm still not sure this is a good idea. Maybe it isn't. I got the idea from mccldwll as I recall, and so thought it was worth a try. The way I have it now seems to be fine as far as the shoulders go, and I've gotten rid of the "line of pressure" problem by having the 2 medium layers towards the top. But I'm still having problems getting my hip area at the right firmness so I don't have lower back pain or hip pain. Too soft and I get lower back pain, too hard and I get hip pain.

Right now I have added an extra 3/4" layer of soft latex under the 1" PU foam becuase I had hip pain last night.. I'll see if that is better, or worse...

Re: A problem I had with ZONING my mattress
Reply #3 Feb 24, 2008 8:03 PM
Joined: Sep 10, 2007
Points: 395
"I got the idea from mccldwll as I recall, and so thought it was worth a try. "

Actually, I suggest that hip area be thicker than shoulders. Figure out minimum amount of foam at whatever ILD is needed for shoulders. Then for hips use higher ILD and whatever thickness is necessary to keep spine level/parallel to floor.
Re: A problem I had with ZONING my mattress
Reply #4 Feb 25, 2008 5:41 AM
Joined: Sep 7, 2007
Points: 476
Jim, try getting some 1/2" HR foam medium to firm for your hip area. Half inch foam is great for fine tuning. You might want to remove the soft foam if it's giving you back pain and add some more HR foam to compensate. I think the density alone provides more padding than the same thickness of soft PU foam, and it definately gives you more support.

What mccldwll makes sense since your hips will sink in more deeply than your shoulders. You sound like me in needing your hips not to sag into the mattress. I had to bolster mine with carpet remnant covered with a flat feather pillow and some HR foam under my 1" visco topper. Visually it's as bit higher than the rest of the mattress, but the stiff jute backing of the carpet remnant keeps my spine straight and the feather pillow and extra foam provide contouring and comfort. It's not perfect, but it will do until I reconstruct my mattress. 

Re: A problem I had with ZONING my mattress
Reply #5 Feb 25, 2008 12:41 PM
Joined: Sep 11, 2007
Points: 111
Cloud9, does the carpet cover your entire bed, or just across the hip area? I'm paying a lot of attention to all of this zoning talk as I think it won't be long before I take apart our mattress.

We have only had the mattress for three months and I can feel the area under my hips that takes the brunt of my weight (all 125 llbs of me) starting to break down. It feels a lot softer than the rest of the bed, but visually looks no different, so I know there is no way that any warranty will come into play.

We have been trying various toppers that I realize are only exacerbating the problem since they contour into the dip made by my hips. I think if I can have something a little more rigid across that area, it will create a better base for a (zoned) topper.

Having the surface under your hips higher than your shoulders as mccldwll says, makes a lot of sense as the hips sink in so much more than the shoulders. I have checked this out by placing a fairly flat down pillow underneath me and can feel the relief on my spine as it is brought more into alignment.

Thanks to Jim and mccldwll for sharing all of their great information about zoning. I'm finding it all very interesting.
Re: A problem I had with ZONING my mattress
Reply #6 Feb 25, 2008 5:28 PM
Location: Mequon, WI
Joined: Aug 30, 2007
Points: 363
kimmcgov wrote:
We have only had the mattress for three months and I can feel the area under my hips that takes the brunt of my weight (all 125 llbs of me) starting to break down. It feels a lot softer than the rest of the bed, but visually looks no different, so I know there is no way that any warranty will come into play.

It might be time to do surgery and remove any foam built in to your mattress and get down to the springs.  Build off of that with new foam.  It is surprising how fast this happens nowadays.
Re: A problem I had with ZONING my mattress
Reply #7 Feb 27, 2008 5:23 AM
Joined: Sep 7, 2007
Points: 476
Kim, at the moment I have two foot mat sized pieces of carpet remnant on the bed. I picked them up at the 99 cent store to experiement. I was thinking of going to a carpeting store and getting a bed-sized remnant cut, but at times I like to move off the really firm area of the mattress on to something softer so I decided to keep things the way they are.

One piece went under the hip area and the other one under the shoulders since I am one of those rare individuals that actually like it firm under my shoulder as well. The hip area also has a flat feather pillow over the carpeting and a sheet of half inch HR foam over the pillow. The shoulder area has a piece of soft eggcrate foam over it. Everything is covered  by a 1" visco topper. I'm not sure the carpeting method will work unless everything is covered by one uniform piece of foam, and it certainly won't work for everyone, but it seems to be working for me.

I was beginning to think it was just my imagination that the foam on the bed felt much softer and less supportive than it did a few months ago, but after reading Jimsocal's post about the foam on his Sealy, I'm sure it actually is much softer. Your post only confirmed it.  Maybe it will be time to do some mattress surgery sooner rather than later.

Re: A problem I had with ZONING my mattress
Reply #8 Feb 27, 2008 3:20 PM
Location: L.A. area
Joined: Jan 18, 2008
Points: 1161
mccldwll wrote:
"I got the idea from mccldwll as I recall, and so thought it was worth a try. "

Actually, I suggest that hip area be thicker than shoulders. Figure out minimum amount of foam at whatever ILD is needed for shoulders. Then for hips use higher ILD and whatever thickness is necessary to keep spine level/parallel to floor.


Right. Now I remember!

Well, thanks to all for your comments and suggestions. My mattress is getting better but I'm still tweaking it.

I'll try some of these suggestions.

Thanks.

Re: A problem I had with ZONING my mattress
Reply #9 Feb 28, 2008 8:35 AM
Joined: Sep 10, 2007
Points: 395
Found this on Beckley (sp?) mattress site--"zoning" with extra materials (and I believe the Holland coil system is also zoned by definition):

"Handfilled: All fillings material is placed in the mattress by hand. This enables the
mattress makers to shape the matterss, putting more material where there will be
the most body weight. This "crowning" of the mattress assures better wear."
Re: A problem I had with ZONING my mattress
Reply #10 Feb 29, 2008 12:07 AM
Location: L.A. area
Joined: Jan 18, 2008
Points: 1161
Okay, so I remade my mattress from the top up today (most people "make their bed", I make my mattress! ;-) )

I won't go into the specifics of what I did yet, but I have 2 questions about zoning it:

1) You guys say to make the hip section thicker. Why thicker and not just more firm?

2) If I do add a layer - do I add it down low, towards the bottom, or towards the top - say, under the topper? And should the added layer for the hip zone be something soft, medium or firm? (I Irecognize these answers may not be definitively answerable but give it your best guess please)

I did add a layer in my hip secton today but I was half asleep when I did it and I think I added it too close to the top and too soft... ;-(

Re: A problem I had with ZONING my mattress
Reply #11 Feb 29, 2008 5:36 AM
Joined: Sep 7, 2007
Points: 476
jimsocal wrote:
Okay, so I remade my mattress from the top up today (most people "make their bed", I make my mattress! ;-) )

I won't go into the specifics of what I did yet, but I have 2 questions about zoning it:

1) You guys say to make the hip section thicker. Why thicker and not just more firm?

2) If I do add a layer - do I add it down low, towards the bottom, or towards the top - say, under the topper? And should the added layer for the hip zone be something soft, medium or firm? (I Irecognize these answers may not be definitively answerable but give it your best guess please)

I did add a layer in my hip secton today but I was half asleep when I did it and I think I added it too close to the top and too soft... ;-(

1) I hit upon making the hip section thicker just by accident: When my old mattress started sagging I stuck an old flattened feather pillow under all my toppers to fill up the ditch. It made the mattress slightly higher there, but I discovered when I slept on it the pillow squashed down under my hips but contoured to my waist making everything more comfortable and supportive. After reading mccldwll's post about the Beckley it seems like I was on to something. Simply put, thicker makes the mattress more comfortable where you are apt to feel pressure points and the contouring offers better support. Firmer on the other hand might just be hard. That's why I had to cover the carpeting--which makes the mattress firmer--with something that also made it comfortable to lie on.

2) I would put everything under the topper. This keeps all the pieces in place and provides a more or less uniform surface. However, if you have multiple layers you might find that placing various components at different levels in relation to the top layer fine tunes your comfort level more effectively. For instance I was experiementing with my 1" Brylane latex topper again. I liked the way it felt under the 1" visco but for some reason my pillow felt a little uncomfortable and I was getting a twinge of fatigue across my shoulder blades. This suggested to me that it was just too soft despite the fact that I had a layer of carpeting underneath the toppers. That got me thinking that I could just move the section of carpeting under my shoulder up one level and place it between the latex and the visco. This is why I like working with 1" layers. They are much more flexible than 2" layers. Moving the carpet section firmed up the shoulder area and fixed the problem.

As to whether the hip area should be soft medium or firm. That's something you'll have to experiement with. Since you have lower back pain and need to keep your hips from sinking into the mattress, I'd say you need to go firm and then tweak the comfort layers as needed. This is where half inch HR foam comes in handy. You can place a layer or two over the firm support material and build it up to eliminate pressure points until you strike the right balance between the two. I'd try to stay away from using really soft foam in the lumbar area. I found this was making my back ache. HR foam is more supportive.

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