Sagging springs vs degrading foam

My current mattress is being replaced shortly anyway, but I’m curious about the claim here that what people usually perceive as a sagging innerspring system is actually poly foam layers wearing away and causing body impressions or dips in the mattress.

Make no mistake about it, the foam layers on my King Koil budget mattress have eroded into nothing and if I were to strip my mattress of all its padding via toppers and pads that I’ve piled on top of it, I’d be sleeping directly on the spring system.

But when I carefully inspect the profile of my mattress and run my hand along the springs, there is a definite valley toward the middle of the mattress. The springs raise higher at the head and foot of the mattress and sink by about an inch in the middle. So this means the mattress I currently have has both inferior foam and an inferior spring system? I can’t tell if its Bonnell or continuous without tearing it open, but how crappy does a spring system have to be to sag along with the foam above it?

Just curious, as my replacement mattress has a continuous coil spring and I’m now terrified that its going to collapse on me too within a short period of time.

Edit: Does having a double sided spring mattress (which is what is coming to me) not only ensure that the comfort layers get worn more evenly and have time to rest, but also the spring system?

Hi pinupchick,

In most cases this is true but of course there are exceptions. With a cheap mattress that has a lower quality innerspring and only thin layers of foam above it … the coils would be subject to more wear an tear and could easily soften or sag. The closer to the top of a mattress a component is … the more weak and tear it is subject to and with thicker foam layers above the coils and with the type of coils that are in most mid quality mattresses or better … the coils would not normally be the weak link of the mattress. With cheaper lower gauge coils that only had thin layers of low quality polyfoam above them … the coils themselves could certainly develop a compression set.

In a mattress like this … the coils could easily become an issue because there is little above them to absorb the pressures of sleeping on the mattress and the coils are likely lower quality.

Generally this would be more common with a low quality mattress. If you are feeling this along the sides of your mattress (rather than inspecting the whole top surface of the springs with the cover and foam removed) … then you could have a bent border wire from sitting on the side of the mattress or it could be the springs themselves. In either case … with the low quality mattress you are describing … the odds are higher that the springs themselves could have an issue.

The springs in the mattress that you bought are likely to last much longer both because the quality of the springs themselves are higher and the amount and quality of the foams over the springs is higher as well. In almost all cases … the springs are not an issue in most mid quality or better mattresses with a reasonable amount of foam over them.

Double sided mattresses will maintain the resiliency and inherent firmness level of the foams better which in turn will lessen the compression and wear on the coils. Coils don’t wear out on one side more than another (they compress evenly throughout the coil no matter which side is being compressed) so flipping a mattress doesn’t directly affect the life of the coils so much as it does the foam above them which in turn helps extend the life of the coils.