(Before I discovered the forum here...) I bought a firm Sealy Posturepedic Reserve bed a month ago. After a few days of sinking in and getting back pain in the morning I visited my parents who have an old Sealy Posturepedic, 1999, but hardly used, in their guest room, and slept over night in it. Their bed supports my back perfectly. (Years ago I compressed my spine, injuring my lower back, so now my back is intolerant of insufficient support.) I decided to undue the seam and take the top off my new bed to see why I was sinking in. I thought it might be the Visco memory foam but...

Here's what I found, bottom up:
(1) 25 springs per square foot. No space in between the springs. Four turns per spring. All the loops were the same size. Springs were interlocked on both sides of each spring with long coils running the width of bed.
(2) Above the springs, there is a thin 1/8" sheet of a polyethylene. Looks like the pic second from the bottom:
http://www.8linx.com/Polyethylene%20_foam.htm
(3) On top of the polyethylene there is a 1" layer of egg-crated polyurethane foam (dense.)
(4) Then a 2.5" layer of egg-crated polyurethane foam (soft) with a strip of Visco memory foam 1/2" x 19.5" x 59" going across the hip section.
(6) There is an edge guard running around the perimeter of polyethylene 2.5" width.
(5) Then the quilted top which feels like it has some fairly dense polyurethane in it.

I immediately recognized the problem was the thick layer of polyurethane foam. In my starving artist days I found some of this, and put two sheets of ~2" medium density egg-crated foam where I was going to sleep. I figured the floor would give the support, and after lying down for a few minutes I thought it would be fine. After the first night I woke up with pain in my lower back. My girlfriend, who had no back injury, also woke up with a sore lower back.

With my new bed I got the pain in the same spot in my lower back. So I took the 2.5" layer of polyurethane out and slept the next night without it. My back was restored in the morning. It was, however, a bit hard, so I ordered a 1" talalay latex topper, 32 ILD, from The Foam Factory, (which has the same address as Foam by Mail.) I put the topper under the quilted top, where that piece of polyurethane used to be. Last night was my first night. The support I got was very good. Like other posters here I wonder if I could have gotten the softer 20 ILD with sufficient support, but since I went from nightmare to restful restoring sleep I can't complain.

I was nervous about taking the bed apart and voiding the warranty, but I was also afraid to spend the $119 for an exchange, at Art Van, only to end up with the same problem. (Seven months ago I bought a Kingsdown medium bed and returned it for the same reasons stated above.) It worked out for the best, now I can sleep sound and wake up restored. And this whole procedure cost less than upgrading to the Sealy Posturepedic Signature Series mattress. It was easy to take the top off–just undue the seam that connects the top to the sides. Eventually I'll re-sew the thing up. In the mean time the fitted sheet holds everything in place.

Lingering Question: It seems strange to me that the quilted top is harder than the 2.5" layer of polyurethane underneath. Is this top layer the only criterion used when labeling the mattress "firm"? I would love to know the anatomy of the other models of mattresses.

I have no affiliation with any companies mentioned above. Also, the forum here is excellent. Thank you!

Matt

Update: After replacing the 2.5" soft polyurethane with 32ILD 1" latex my back was supported much better, but after a few days I noticed the edge of my bed was higher than the middle where a rut was being developed. So I took out the 1" dense polyurethane foam, then put the top back on. Now, after a week, there is no rut; the middle and the edge of the bed feel the same. From my experience, I'd say polyurethane is not a good thing to put in a mattress.

This model is made for the European market,but it can be found in the USA market aswell. The price was 1000.00 Euro.
I wanted so bad a bigger and fluffy pillowtop but so far Sealy has just recently ventured in the Italian market with the pillowtop product,so they only have a not so fluffy pillowtop mattress.
Good choice.No more aches or pains in the morning as i used to have with the usesless Tempur. It tend to hammock a bit too soon,so it has to be rotated once a month.

My wife and I bought a Sealy Fenway at CostCo 4 years ago.

At first it seemed as good as any other, but about 6 months ago (do that math, that's only a 3 and 1/2 year old bed) it started giving us big backaches. It actually began to bother us before that but we thought it was because of our car accident, not the bed. Read on and you will see that it was the bed.

Since they are not "turn over" beds (one side only) there was not much we could do.

What we have discovered is that this mattress is sinking too much when we lay on it. I'm only 175lb and my wife is 145 lb so this should not be happening. My back was absolutely KILLING me.

We did surgery on this bed. We cut it open with an exacto knife and found 4" of the crappiest foam you can get. This bed was never made to give support, it was simply made to feel good at first and then give out. The kind of foam they put in there simply is not made to last more than a year or two. Period.

See my thread:
"Dissecting my Sealy Fenway mattress bought at CostCo 4 years ago: Lousy soft foam inside!"