Mattress Forum

If you get just the 3" of 40, you can try folding it half ( for testing purposes) and putting on your 2" of other latex.  That will help you tell what you want to do with the next 3".  However, there is nothing like sleeping a whole night on it to really know.  Maybe one off  you could try it on your own if you have a spare bed. 
 

How thick, wide and far a part are your slats?  Is there any center support?

Are you sure your current springs are bad?  How old and what brand? Did you remove all of the foam and put in your 2" of latex and it is still too soft?  Does it sag in a lot if you like directly on the springs?

To be fair, the springs probably aren't completely shot. But where we each sleep there's a noticeable dip, with the usual hump running down the middle. They springs have lost the firmness we bought the mattress for. It was made by a local company, their "top of the line," and we got it about two years ago. It's possible there are Serta parts. The company seems to have some sort of partnership with them.

Several months ago I ripped out the original foam and replaced it with the 32 ild from FBM. That improved things somewhat, but the dip is still there, if less significant. As far as my back is concerned, though, it's more or less the same.

I just rolled back the latex to check the springs themselves and I realize that when I pulled up the PU foam I left the gray, woolly looking stuff that directly covers the springs. I assumed that needed to be there to protect the latex from tearing. I wonder if some of the dip might be in there. There's at least an inch of it. Maybe 1 1/2". Is it safe to rip that out?

I suppose it's possible that a firmer piece of latex on top of the springs might lessen the dip more than the 2" of 32 ild currently does. Maybe the topper just isn't firm enough. But it still feels like some degree of dip will be there no matter what. But maybe with something firmer between me and the springs it can be mitigated to the point that my back doesn't mind.

a-bear,

Proviso: My suggestions are not based on personal experience with latex.

I'm in the process of returning a spring mattress I've had for a month due to it being too oft and causing some lower back pain. To my knowledge, I have no experience sleeping on latex, but I have been following thread here for a couple weeks and reading up on various ways to skin the cat. I am very slender, 5'10" @ 135lbs., however I am very muscular with broad shoulders. I like a firm mattress for support (I too have spent much time on futons and floors).  I sleep on side, back, and stomach, but my current spring mattress is too soft for stomach sleep. The crux seems to be arriving at something firm enough to be supportive, while still relieving any pressure points and remaining comfortable to sleep.

You might consider the ‘zoning’ method whereby different body areas receive different firmness levels. To use my example, since I like a firm mattress but have broad shoulders – which have been injured in the past – a firm mattress that provides sufficient back support might be too firm to allow enough deflection for my broad shoulders, potentially forcing my spine out of alignment as well as causing a pressure point at the shoulder area. You could zone both your side and your partner’s side separately, or just zone your side. I believe it could be done as a DIY construction without too much difficulty.

Also, if you buy a 3” thick piece as part of a foundation, you can fold it in half to make a 6” piece for testing purposes, ditto with your topper…that may give you enough feedback before buying additional pieces.

One additional thought (I will start a new thread on this in a day or so) is the use of a stiffening layer, of different material other than foam, between two foam layers. This may be another way to increase firmness, and might also be used if you try a zoning approach. 

Hmmm, possibly cheap springs.  They shouldn't give out that quickly.  Where kids jumping on it or anything like that?  Do you know if the coils are interlaced (wired to each other) or individual pocketed coils?  You should be able to tell by looking under the gray thing.  I have heard that some of the wiring they use to connect the coils is not that great now a days and maybe that has gone bad (Budgy, any opinions if you are reading this?).

I am surprised that the gray wooly stuff would be 1" or more thick.  Maybe you could try taking that out, but is there then nothing else above the coils?   Probably not the best to put the latex directly on the coils, but maybe you could spread out an old blanket or something like that.  I doubt the gray thing is the problem if it is not foam, but you never know until you try.

If the springs are truly dipping then you probably are best replacing them with a firm latex base.
 

Yes, it's entirely possible my toddler helped to hasten the springs' demise, despite our efforts to keep him off. He doesn't weigh a whole lot, but more than once we've caught him bouncing around.

The springs are interlaced. I just measured, and there appears to be 1" of the gray stuff. It's hard to measure because it sort of sinks into the springs. I have no idea what it's made of (partly foam of some sort, I'm sure—maybe cotton, too, or something cottony), but there's nothing else above the springs.

If I'm going to get a 3" piece of 40 ild anyway, I could always throw it on top and see what happens. If nothing else it would give us something to sleep on if we decided to order another 3" piece.

Trying to guess what the solution might be is frustrating work. If I knew only a zoned flobed would make my back happy, I'd buy one. But it's hard to spend that kind of money when it still seems perfectly likely that there's a much cheaper DIY solution. Then again, I fear the inevitable creep, ending up spending just as much for pieces that still don't make a satisfying whole.

It wasn't that long ago that a $100 futon felt perfect. I don't know if I'm just getting old or if it's just these particular springs.

If the springs are still usable, I could experiment with a 1" 40 ild topper instead of the 3" I'd been planning on (when I thought the springs would have to be tossed).

But would 1" be enough to offset springs that feel too soft? There's also the 44 ild option. Right now, the combination of springs and  2" of 32 ild are too soft.

Can you define by what you mean by the dip?  Is it visible?  Does that area of the springs feel softer than other areas (at feet and head)?   Quite frankly, 2" of 32 ILD right on the springs should be pretty firm.  If that is too soft then I think they are not the right springs for you. 

Can you tell if the latex indeed feels like 32?  FBM seems to have a varying degree of reliability of what they sell.
 

This is the only latex I've owned, so I have no means for comparison. It's certainly a lot firmer than what came with the bed, but unfortunately I don't know what 32 ild should feel like.

You might be right that I just need a firmer core.

Do they put extra support in the middle of a king bed (I have only dealt with queens)?  If not, then it sounds like the springs have definitely lost something.  The springs in the middle (assuming no extra support there) are probably close to the firmness was like when new (since they don't get used much), and the sides are broken in and less firm now.

I have one further thought.  What is the box spring like?  Does that seem too soft?  That could be part of the problem as well.

Budgy, if you are out there do you have any opinions on this?