Mattress Forum

You can't know until you open up the mattress whether the sag is from the springs but it is most likely from the foam.

So you throw out ALL the foam if you have at least 2" to replace it (Okay, hold on to the foam for a night or two in case you need to add some more back in, but certainly the top layers will be shot.)

Add your good quality foam - or even new cheap PU foam, but you need something at least medium ILD, not a "topper" - for the bottom layer - and you may decide you don't need your new mattress that's on the way.

Or if you're like some of us, and prefer the feel of springs under you, and if your springs are shot, then you can just go out and buy a new mattress, super firm, which will be the cheapest in the store, (buying pillowtops costs more, and is the worst thing to buy), then try your toppers on top of that, and if that still doesn't work, open it up and replace the cheap foam inside with your new latex.

I know people feel very reluctant to cut open a brand new mattress, but due to the way the S co's make mattresses nowadays, it is necessary if you want a good night's sleep. As long as you know you are getting the right type of springs and good quality ones, then it's no problem, it WILL work. It may take some adjustment of various ILD's of latex but you will end up with a mattress that will give you comfort for years, whereas the way the new mattress is, it will for sure wear out in a week, a month, a year or two...

But as Sandman says, if you think you like the feel of pure latex, with no springs, you can go that route too just by buying a latex core. Another cheaper option is to buy a pure M-grade foam core at Overnightmattress.com and put your latex on top of that. I do not recommend buying their mattresses with the memory foam attached, though; just get the basic M-grade foam core. This may or may not feel as good as pure latex, to you, or it may; depends on the person. If you don't like it you can return it within 120 days for a full refund as long as it's PERFECTLY clean (not one hair stuck to it, etc...) Best thing to do is keep the foam in the casing and never open it.
 

Thank you all for your reponses!

It is a pillowtop. If I cut it open, will it be clear to me - someone who has never seen the inner workings of a mattress before - whether it is the springs or the PU foam? Also, do I just remove all of the foam and replace it with the foam you suggested cut to the measurements of the mattress? I know it's a silly question, but this is all so new to me.
 

Best to use something like a box cutter to cut open.  Mine was pretty easy.  Maybe took 15 minutes.

If you buy the standard size foam for the size of you mattress, you should be able put it right inside.  A tight mattress pad/cover will hold it in place.

I currently use 2" of 32 ILD 100% natural talalay latex + 1" of 24ILD 100% natural talalay latex (both from rockymountain mattress) + 1" of mem-cool memory foam from overstock.  All were standard queen size pieces. 

Thanks for the reply. Just to clarify, I do know the difference between foam and springs, but wondered if I'd know if the springs are the problem or if the foam is the problem, just by looking at all of it. It was all so clear in my head while I was typing the question

Definately looking forward to my surgery - thanks for all of the tips!

Sorry, I misinterpreted your question.  I was a little worried if you could not tell the foam from the springs!   

If you cut the top of and take out the foam, I would suggest gently laying right on top of the springs (maybe covered by  a blanket if they are not covered), to see if they seem pretty firm or if they seem to noticably sag in the area where the whole mattress sags currently.    Hopefully they will seem pretty firm on both sides and in the middle.   In which case you might just need to add a few inches of new foam and may be set for several more years.    If the springs seem to sag a lot without any foam, then you probably need to scrap the whole thing. 

You can also inspect the foam to see if it looks compressed / matted down or something like that.  It might be hard to tell visually though. 

You can always put the old foam and cover back on and cover with a mattress pad. 

Anyway, then take off all the foam as Sandman said, then lay on it and see if it feels like it's dipping in the middle, without the foam (you could leave the very bottom layer of whatever it is they have on there - god knows what it might be; could be some kind of burlap type stuff or a plastic-like material or a thin layer of foam. So anyway, lay on it and see if you feel the dip. If you do, game over, you lost: the springs are shot. (Unless it's a flippable mattress, then you can try the other side...)

If you don't feel a dip in the springs themselves, then you could try just removing the top most 2-3 pieces of foam and lay on that and see if it now feels a bit better.

Then if it feels like it's no longer dipping as much, buy yourself some latex. If it's a queen, buy queen sized latex, it'll fit. Any piece you might get that is too big can be easily cut to fit with an electric meat carving knife. Cuts like a hot knife through butter.

Now you're only question is how much foam do you really want? You won't probably need as many inches of foam as you had before, usually 2-4" will be enough. I use about 3", Sandman likes a little more.

Let us know how it turns out, and post photos if it's not too much hassle. Here's how to post photos:

How to insert pictures:

1.  Select 'New Topic' or "Reply"
2.  Enter text in the message area you wish to have surround the picture you are planning to add.
3.  Select the 'Insert/Edit Image' icon just left of the smiley face, just above the message area.  A small window pops up.
4.  In this window type the URL of the image you wish to insert.  It should begin with 'http://"  and end with ".gif" or ".jpg".  Where it says alternative text type a quick description of the photo. Click OK.
4b.  If the picture is on your personal hard drive you will need to first upload it to a picture sharing/storage service like Flickr or imageshack.com.  Once the picture is on that site you can simply cut and paste the URL of the image into the small window in step 4. On imageshack, after you've uploaded the picture, use the url next to where it says "Direct": copy and paste that url where it says url in the pop-up window here.

Great! I look forward to your experiment! I'm also pretty confident it will work out for you. Springs, especially with lots of padding on top, probably have not worn out, unless someone jumped on them a lot or something... but then again, if they're old... well, good luck!

If you do post pictures, please start a new thread "My Serta Mattress Surgery" or something...